From 19d081ef1d1b806117fcaf61dbfaaf2ba59cc127 Mon Sep 17 00:00:00 2001
From: rwaldron <waldron.rick@gmail.com>
Date: Thu, 12 Aug 2021 16:28:19 -0400
Subject: [PATCH] Transform legacy format to harness assertions:
 test/built-ins/O*/**/*.js

---
 test/built-ins/Object/S15.2.1.1_A1_T1.js      |  36 +--
 test/built-ins/Object/S15.2.1.1_A1_T2.js      |  36 +--
 test/built-ins/Object/S15.2.1.1_A1_T3.js      |  36 +--
 test/built-ins/Object/S15.2.1.1_A1_T4.js      |  36 +--
 test/built-ins/Object/S15.2.1.1_A1_T5.js      |  36 +--
 test/built-ins/Object/S15.2.1.1_A2_T1.js      |  23 +-
 test/built-ins/Object/S15.2.1.1_A2_T10.js     |  11 +-
 test/built-ins/Object/S15.2.1.1_A2_T11.js     |  21 +-
 test/built-ins/Object/S15.2.1.1_A2_T12.js     |  19 +-
 test/built-ins/Object/S15.2.1.1_A2_T13.js     |  23 +-
 test/built-ins/Object/S15.2.1.1_A2_T14.js     |  18 +-
 test/built-ins/Object/S15.2.1.1_A2_T2.js      |  23 +-
 test/built-ins/Object/S15.2.1.1_A2_T3.js      |  23 +-
 test/built-ins/Object/S15.2.1.1_A2_T4.js      |  11 +-
 test/built-ins/Object/S15.2.1.1_A2_T5.js      |  17 +-
 test/built-ins/Object/S15.2.1.1_A2_T6.js      |  23 +-
 test/built-ins/Object/S15.2.1.1_A2_T7.js      |  23 +-
 test/built-ins/Object/S15.2.1.1_A2_T8.js      |  11 +-
 test/built-ins/Object/S15.2.1.1_A2_T9.js      |  18 +-
 test/built-ins/Object/S15.2.1.1_A3_T1.js      |  16 +-
 test/built-ins/Object/S15.2.1.1_A3_T2.js      |  11 +-
 test/built-ins/Object/S15.2.1.1_A3_T3.js      |  16 +-
 test/built-ins/Object/S15.2.2.1_A1_T1.js      |  33 +--
 test/built-ins/Object/S15.2.2.1_A1_T2.js      |  33 +--
 test/built-ins/Object/S15.2.2.1_A1_T3.js      |  33 +--
 test/built-ins/Object/S15.2.2.1_A1_T4.js      |  33 +--
 test/built-ins/Object/S15.2.2.1_A1_T5.js      |  33 +--
 test/built-ins/Object/S15.2.2.1_A2_T1.js      |  11 +-
 test/built-ins/Object/S15.2.2.1_A2_T2.js      |  12 +-
 test/built-ins/Object/S15.2.2.1_A2_T3.js      |  11 +-
 test/built-ins/Object/S15.2.2.1_A2_T5.js      |  12 +-
 test/built-ins/Object/S15.2.2.1_A2_T6.js      |  13 +-
 test/built-ins/Object/S15.2.2.1_A2_T7.js      |  26 +-
 test/built-ins/Object/S15.2.2.1_A3_T1.js      |  28 +-
 test/built-ins/Object/S15.2.2.1_A3_T2.js      |  28 +-
 test/built-ins/Object/S15.2.2.1_A3_T3.js      |  23 +-
 test/built-ins/Object/S15.2.2.1_A4_T1.js      |  31 +--
 test/built-ins/Object/S15.2.2.1_A4_T2.js      |  31 +--
 test/built-ins/Object/S15.2.2.1_A4_T3.js      |  26 +-
 test/built-ins/Object/S15.2.2.1_A5_T1.js      |  28 +-
 test/built-ins/Object/S15.2.2.1_A5_T2.js      |  16 +-
 test/built-ins/Object/S15.2.2.1_A5_T3.js      |  28 +-
 test/built-ins/Object/S15.2.2.1_A5_T4.js      |  23 +-
 test/built-ins/Object/S15.2.2.1_A6_T1.js      |  17 +-
 test/built-ins/Object/S15.2.2.1_A6_T2.js      |  11 +-
 test/built-ins/Object/S15.2.2.1_A6_T3.js      |  18 +-
 test/built-ins/Object/S15.2.3_A1.js           |   8 +-
 test/built-ins/Object/S15.2.3_A2.js           |   9 +-
 test/built-ins/Object/S15.2.3_A3.js           |  14 +-
 test/built-ins/Object/S15.2_A1.js             |   4 +-
 test/built-ins/Object/S9.9_A3.js              |  41 +--
 test/built-ins/Object/S9.9_A4.js              | 252 ++++++++----------
 test/built-ins/Object/S9.9_A5.js              |  94 +++----
 test/built-ins/Object/S9.9_A6.js              |  26 +-
 .../Object/assign/Source-Null-Undefined.js    |   2 +-
 .../assign/Source-Number-Boolen-Symbol.js     |   2 +-
 test/built-ins/Object/assign/Source-String.js |   6 +-
 .../Object/defineProperty/S15.2.3.6_A1.js     |   4 +-
 .../Object/defineProperty/S15.2.3.6_A2.js     |   8 +-
 .../getOwnPropertyNames/S15.2.3.4_A1_T1.js    |   4 +-
 .../Object/prototype/S15.2.3.1_A1.js          |  12 +-
 .../Object/prototype/S15.2.3.1_A2.js          |  20 +-
 .../Object/prototype/S15.2.3.1_A3.js          |  14 +-
 .../Object/prototype/S15.2.4_A1_T1.js         |  10 +-
 .../Object/prototype/S15.2.4_A1_T2.js         |  15 +-
 test/built-ins/Object/prototype/S15.2.4_A2.js |   5 +-
 test/built-ins/Object/prototype/S15.2.4_A3.js |   2 +-
 test/built-ins/Object/prototype/S15.2.4_A4.js |   2 +-
 .../prototype/constructor/S15.2.4.1_A1_T1.js  |  10 +-
 .../prototype/constructor/S15.2.4.1_A1_T2.js  |  30 +--
 .../prototype/hasOwnProperty/S15.2.4.5_A12.js |   2 +-
 .../prototype/hasOwnProperty/S15.2.4.5_A13.js |   2 +-
 .../hasOwnProperty/S15.2.4.5_A1_T1.js         |  19 +-
 .../hasOwnProperty/S15.2.4.5_A1_T2.js         |  36 +--
 .../hasOwnProperty/S15.2.4.5_A1_T3.js         |  34 +--
 .../prototype/hasOwnProperty/S15.2.4.5_A6.js  |  11 +-
 .../prototype/hasOwnProperty/S15.2.4.5_A7.js  |   6 +-
 .../propertyIsEnumerable/S15.2.4.7_A10.js     |  20 +-
 .../propertyIsEnumerable/S15.2.4.7_A11.js     |  18 +-
 .../propertyIsEnumerable/S15.2.4.7_A12.js     |   2 +-
 .../propertyIsEnumerable/S15.2.4.7_A13.js     |   2 +-
 .../propertyIsEnumerable/S15.2.4.7_A1_T1.js   |  38 +--
 .../propertyIsEnumerable/S15.2.4.7_A2_T1.js   |  19 +-
 .../propertyIsEnumerable/S15.2.4.7_A2_T2.js   |  35 ++-
 .../propertyIsEnumerable/S15.2.4.7_A6.js      |  11 +-
 .../propertyIsEnumerable/S15.2.4.7_A7.js      |   6 +-
 .../propertyIsEnumerable/S15.2.4.7_A8.js      |  24 +-
 .../propertyIsEnumerable/S15.2.4.7_A9.js      |  18 +-
 .../prototype/toLocaleString/S15.2.4.3_A1.js  |  28 +-
 .../prototype/toLocaleString/S15.2.4.3_A10.js |  20 +-
 .../prototype/toLocaleString/S15.2.4.3_A11.js |  18 +-
 .../prototype/toLocaleString/S15.2.4.3_A12.js |   2 +-
 .../prototype/toLocaleString/S15.2.4.3_A13.js |   2 +-
 .../prototype/toLocaleString/S15.2.4.3_A6.js  |  11 +-
 .../prototype/toLocaleString/S15.2.4.3_A7.js  |   6 +-
 .../prototype/toLocaleString/S15.2.4.3_A8.js  |  24 +-
 .../prototype/toLocaleString/S15.2.4.3_A9.js  |  25 +-
 .../Object/prototype/valueOf/S15.2.4.4_A10.js |  20 +-
 .../Object/prototype/valueOf/S15.2.4.4_A11.js |  18 +-
 .../Object/prototype/valueOf/S15.2.4.4_A12.js |   2 +-
 .../Object/prototype/valueOf/S15.2.4.4_A13.js |   2 +-
 .../Object/prototype/valueOf/S15.2.4.4_A14.js |   2 +-
 .../Object/prototype/valueOf/S15.2.4.4_A15.js |   7 +-
 .../prototype/valueOf/S15.2.4.4_A1_T1.js      |  21 +-
 .../prototype/valueOf/S15.2.4.4_A1_T2.js      |  21 +-
 .../prototype/valueOf/S15.2.4.4_A1_T3.js      |  21 +-
 .../prototype/valueOf/S15.2.4.4_A1_T4.js      |  21 +-
 .../prototype/valueOf/S15.2.4.4_A1_T5.js      |  21 +-
 .../prototype/valueOf/S15.2.4.4_A1_T6.js      |  21 +-
 .../prototype/valueOf/S15.2.4.4_A1_T7.js      |  21 +-
 .../Object/prototype/valueOf/S15.2.4.4_A6.js  |  11 +-
 .../Object/prototype/valueOf/S15.2.4.4_A7.js  |   6 +-
 .../Object/prototype/valueOf/S15.2.4.4_A8.js  |  24 +-
 .../Object/prototype/valueOf/S15.2.4.4_A9.js  |  25 +-
 114 files changed, 903 insertions(+), 1439 deletions(-)

diff --git a/test/built-ins/Object/S15.2.1.1_A1_T1.js b/test/built-ins/Object/S15.2.1.1_A1_T1.js
index 1964b17703..459df4fb02 100644
--- a/test/built-ins/Object/S15.2.1.1_A1_T1.js
+++ b/test/built-ins/Object/S15.2.1.1_A1_T1.js
@@ -13,22 +13,28 @@ var __obj = Object(null);
 
 var n__obj = new Object(null);
 
-if (__obj.toString() !== n__obj.toString()) {
-  throw new Test262Error('#1');
-}
+assert.sameValue(
+  __obj.toString(),
+  n__obj.toString(),
+  '__obj.toString() must return the same value returned by n__obj.toString()'
+);
 
-if (__obj.constructor !== n__obj.constructor) {
-  throw new Test262Error('#2');
-}
+assert.sameValue(
+  __obj.constructor,
+  n__obj.constructor,
+  'The value of __obj.constructor is expected to equal the value of n__obj.constructor'
+);
 
-if (__obj.prototype !== n__obj.prototype) {
-  throw new Test262Error('#3');
-}
+assert.sameValue(
+  __obj.prototype,
+  n__obj.prototype,
+  'The value of __obj.prototype is expected to equal the value of n__obj.prototype'
+);
 
-if (__obj.toLocaleString() !== n__obj.toLocaleString()) {
-  throw new Test262Error('#4');
-}
+assert.sameValue(
+  __obj.toLocaleString(),
+  n__obj.toLocaleString(),
+  '__obj.toLocaleString() must return the same value returned by n__obj.toLocaleString()'
+);
 
-if (typeof __obj !== typeof n__obj) {
-  throw new Test262Error('#5');
-}
+assert.sameValue(typeof __obj, typeof n__obj, 'The value of `typeof __obj` is expected to be typeof n__obj');
diff --git a/test/built-ins/Object/S15.2.1.1_A1_T2.js b/test/built-ins/Object/S15.2.1.1_A1_T2.js
index 9ce97bed60..f2b9b9c88a 100644
--- a/test/built-ins/Object/S15.2.1.1_A1_T2.js
+++ b/test/built-ins/Object/S15.2.1.1_A1_T2.js
@@ -16,22 +16,28 @@ var __obj = Object(void 0);
 var n__obj = new Object(void 0);
 
 
-if (__obj.toString() !== n__obj.toString()) {
-  throw new Test262Error('#1');
-}
+assert.sameValue(
+  __obj.toString(),
+  n__obj.toString(),
+  '__obj.toString() must return the same value returned by n__obj.toString()'
+);
 
-if (__obj.constructor !== n__obj.constructor) {
-  throw new Test262Error('#2');
-}
+assert.sameValue(
+  __obj.constructor,
+  n__obj.constructor,
+  'The value of __obj.constructor is expected to equal the value of n__obj.constructor'
+);
 
-if (__obj.prototype !== n__obj.prototype) {
-  throw new Test262Error('#3');
-}
+assert.sameValue(
+  __obj.prototype,
+  n__obj.prototype,
+  'The value of __obj.prototype is expected to equal the value of n__obj.prototype'
+);
 
-if (__obj.toLocaleString() !== n__obj.toLocaleString()) {
-  throw new Test262Error('#4');
-}
+assert.sameValue(
+  __obj.toLocaleString(),
+  n__obj.toLocaleString(),
+  '__obj.toLocaleString() must return the same value returned by n__obj.toLocaleString()'
+);
 
-if (typeof __obj !== typeof n__obj) {
-  throw new Test262Error('#5');
-}
+assert.sameValue(typeof __obj, typeof n__obj, 'The value of `typeof __obj` is expected to be typeof n__obj');
diff --git a/test/built-ins/Object/S15.2.1.1_A1_T3.js b/test/built-ins/Object/S15.2.1.1_A1_T3.js
index 1a5ebc6265..bf4c3f9e3c 100644
--- a/test/built-ins/Object/S15.2.1.1_A1_T3.js
+++ b/test/built-ins/Object/S15.2.1.1_A1_T3.js
@@ -13,22 +13,28 @@ var __obj = Object();
 
 var n__obj = new Object();
 
-if (__obj.toString() !== n__obj.toString()) {
-  throw new Test262Error('#1');
-}
+assert.sameValue(
+  __obj.toString(),
+  n__obj.toString(),
+  '__obj.toString() must return the same value returned by n__obj.toString()'
+);
 
-if (__obj.constructor !== n__obj.constructor) {
-  throw new Test262Error('#2');
-}
+assert.sameValue(
+  __obj.constructor,
+  n__obj.constructor,
+  'The value of __obj.constructor is expected to equal the value of n__obj.constructor'
+);
 
-if (__obj.prototype !== n__obj.prototype) {
-  throw new Test262Error('#3');
-}
+assert.sameValue(
+  __obj.prototype,
+  n__obj.prototype,
+  'The value of __obj.prototype is expected to equal the value of n__obj.prototype'
+);
 
-if (__obj.toLocaleString() !== n__obj.toLocaleString()) {
-  throw new Test262Error('#4');
-}
+assert.sameValue(
+  __obj.toLocaleString(),
+  n__obj.toLocaleString(),
+  '__obj.toLocaleString() must return the same value returned by n__obj.toLocaleString()'
+);
 
-if (typeof __obj !== typeof n__obj) {
-  throw new Test262Error('#5');
-}
+assert.sameValue(typeof __obj, typeof n__obj, 'The value of `typeof __obj` is expected to be typeof n__obj');
diff --git a/test/built-ins/Object/S15.2.1.1_A1_T4.js b/test/built-ins/Object/S15.2.1.1_A1_T4.js
index 067271461f..a884b00e45 100644
--- a/test/built-ins/Object/S15.2.1.1_A1_T4.js
+++ b/test/built-ins/Object/S15.2.1.1_A1_T4.js
@@ -13,22 +13,28 @@ var __obj = Object(undefined);
 
 var n__obj = new Object(undefined);
 
-if (__obj.toString() !== n__obj.toString()) {
-  throw new Test262Error('#1');
-}
+assert.sameValue(
+  __obj.toString(),
+  n__obj.toString(),
+  '__obj.toString() must return the same value returned by n__obj.toString()'
+);
 
-if (__obj.constructor !== n__obj.constructor) {
-  throw new Test262Error('#2');
-}
+assert.sameValue(
+  __obj.constructor,
+  n__obj.constructor,
+  'The value of __obj.constructor is expected to equal the value of n__obj.constructor'
+);
 
-if (__obj.prototype !== n__obj.prototype) {
-  throw new Test262Error('#3');
-}
+assert.sameValue(
+  __obj.prototype,
+  n__obj.prototype,
+  'The value of __obj.prototype is expected to equal the value of n__obj.prototype'
+);
 
-if (__obj.toLocaleString() !== n__obj.toLocaleString()) {
-  throw new Test262Error('#4');
-}
+assert.sameValue(
+  __obj.toLocaleString(),
+  n__obj.toLocaleString(),
+  '__obj.toLocaleString() must return the same value returned by n__obj.toLocaleString()'
+);
 
-if (typeof __obj !== typeof n__obj) {
-  throw new Test262Error('#5');
-}
+assert.sameValue(typeof __obj, typeof n__obj, 'The value of `typeof __obj` is expected to be typeof n__obj');
diff --git a/test/built-ins/Object/S15.2.1.1_A1_T5.js b/test/built-ins/Object/S15.2.1.1_A1_T5.js
index ba66948dfc..00baccf5fb 100644
--- a/test/built-ins/Object/S15.2.1.1_A1_T5.js
+++ b/test/built-ins/Object/S15.2.1.1_A1_T5.js
@@ -13,24 +13,30 @@ var __obj = Object(x);
 
 var n__obj = new Object(x);
 
-if (__obj.toString() !== n__obj.toString()) {
-  throw new Test262Error('#1');
-}
+assert.sameValue(
+  __obj.toString(),
+  n__obj.toString(),
+  '__obj.toString() must return the same value returned by n__obj.toString()'
+);
 
-if (__obj.constructor !== n__obj.constructor) {
-  throw new Test262Error('#2');
-}
+assert.sameValue(
+  __obj.constructor,
+  n__obj.constructor,
+  'The value of __obj.constructor is expected to equal the value of n__obj.constructor'
+);
 
-if (__obj.prototype !== n__obj.prototype) {
-  throw new Test262Error('#3');
-}
+assert.sameValue(
+  __obj.prototype,
+  n__obj.prototype,
+  'The value of __obj.prototype is expected to equal the value of n__obj.prototype'
+);
 
-if (__obj.toLocaleString() !== n__obj.toLocaleString()) {
-  throw new Test262Error('#4');
-}
+assert.sameValue(
+  __obj.toLocaleString(),
+  n__obj.toLocaleString(),
+  '__obj.toLocaleString() must return the same value returned by n__obj.toLocaleString()'
+);
 
-if (typeof __obj !== typeof n__obj) {
-  throw new Test262Error('#5');
-}
+assert.sameValue(typeof __obj, typeof n__obj, 'The value of `typeof __obj` is expected to be typeof n__obj');
 
 var x;
diff --git a/test/built-ins/Object/S15.2.1.1_A2_T1.js b/test/built-ins/Object/S15.2.1.1_A2_T1.js
index e6eb529ad0..2b40746b07 100644
--- a/test/built-ins/Object/S15.2.1.1_A2_T1.js
+++ b/test/built-ins/Object/S15.2.1.1_A2_T1.js
@@ -11,24 +11,11 @@ description: Calling Object function with boolean argument value
 
 var bool = true;
 
-if (typeof bool !== 'boolean') {
-  throw new Test262Error('#1: bool should be boolean primitive');
-}
+assert.sameValue(typeof bool, 'boolean', 'The value of `typeof bool` is expected to be "boolean"');
 
 var obj = Object(bool);
 
-if (obj.constructor !== Boolean) {
-  throw new Test262Error('#2: Object(true) returns ToObject(true)');
-}
-
-if (typeof obj !== "object") {
-  throw new Test262Error('#3: Object(true) returns ToObject(true)');
-}
-
-if (!obj) {
-  throw new Test262Error('#4: Object(true) returns ToObject(true)');
-}
-
-if (obj === true) {
-  throw new Test262Error('#5: Object(true) returns ToObject(true)');
-}
+assert.sameValue(obj.constructor, Boolean, 'The value of obj.constructor is expected to equal the value of Boolean');
+assert.sameValue(typeof obj, "object", 'The value of `typeof obj` is expected to be "object"');
+assert(!!obj, 'The value of !!obj is expected to be true');
+assert.notSameValue(obj, true, 'The value of obj is not true');
diff --git a/test/built-ins/Object/S15.2.1.1_A2_T10.js b/test/built-ins/Object/S15.2.1.1_A2_T10.js
index ee98f99a3a..9ea976fb43 100644
--- a/test/built-ins/Object/S15.2.1.1_A2_T10.js
+++ b/test/built-ins/Object/S15.2.1.1_A2_T10.js
@@ -11,16 +11,11 @@ description: Calling Object function with array of numbers as argument value
 
 var arr = [1, 2, 3];
 
-//CHECK#1
-if (typeof arr !== 'object') {
-  throw new Test262Error('#1: arr = [1,2,3] is NOT an object');
-}
+assert.sameValue(typeof arr, 'object', 'The value of `typeof arr` is expected to be "object"');
 
 var n_obj = Object(arr);
 
 arr.push(4);
 
-//CHECK#2
-if ((n_obj !== arr) || (n_obj[3] !== 4)) {
-  throw new Test262Error('#2: Object([1,2,3]) returns ToObject([1,2,3])');
-}
+assert.sameValue(n_obj, arr, 'The value of n_obj is expected to equal the value of arr');
+assert.sameValue(n_obj[3], 4, 'The value of n_obj[3] is expected to be 4');
diff --git a/test/built-ins/Object/S15.2.1.1_A2_T11.js b/test/built-ins/Object/S15.2.1.1_A2_T11.js
index e61e0dbe98..6cfea71dd1 100644
--- a/test/built-ins/Object/S15.2.1.1_A2_T11.js
+++ b/test/built-ins/Object/S15.2.1.1_A2_T11.js
@@ -8,22 +8,17 @@ info: |
 es5id: 15.2.1.1_A2_T11
 description: Calling Object function with function declaration as argument value
 ---*/
-
-//CHECK#1
-if (typeof func !== 'undefined') {
-  throw new Test262Error('#1:  function expression can\'t be declarated');
-}
+assert.sameValue(typeof func, 'undefined', 'The value of `typeof func` is expected to be "undefined"');
 
 var n_obj = Object(function func() {
   return 1;
 });
 
-//CHECK#2
-if ((n_obj.constructor !== Function) || (n_obj() !== 1)) {
-  throw new Test262Error('#2: Object(function func(){return 1;}) returns function');
-}
+assert.sameValue(
+  n_obj.constructor,
+  Function,
+  'The value of n_obj.constructor is expected to equal the value of Function'
+);
+assert.sameValue(n_obj(), 1, 'n_obj() must return 1')
+assert.sameValue(typeof func, 'undefined', 'The value of `typeof func` is expected to be "undefined"');
 
-//CHECK#3
-if (typeof func !== 'undefined') {
-  throw new Test262Error('#3:  function expression can\'t be declarated');
-}
diff --git a/test/built-ins/Object/S15.2.1.1_A2_T12.js b/test/built-ins/Object/S15.2.1.1_A2_T12.js
index 6df2800f57..8b05f7a4d2 100644
--- a/test/built-ins/Object/S15.2.1.1_A2_T12.js
+++ b/test/built-ins/Object/S15.2.1.1_A2_T12.js
@@ -13,18 +13,7 @@ var obj = Object(1.1 * ([].length + {
   q: 1
 }["q"]));
 
-//CHECK#2
-if (typeof obj !== "object") {
-  throw new Test262Error('#2: Object(expression) returns ToObject(expression)');
-}
-
-//CHECK#3
-if (obj.constructor !== Number) {
-  throw new Test262Error('#3: Object(expression) returns ToObject(expression)');
-}
-
-//CHECK#4
-if ((obj != 1.1) || (obj === 1.1)) {
-  throw new Test262Error('#4: Object(expression) returns ToObject(expression)');
-}
-//
+assert.sameValue(typeof obj, "object", 'The value of `typeof obj` is expected to be "object"');
+assert.sameValue(obj.constructor, Number, 'The value of obj.constructor is expected to equal the value of Number');
+assert(obj == 1.1, 'The result of evaluating (obj == 1.1) is expected to be true');
+assert.notSameValue(obj, 1.1, 'The value of obj is not 1.1');
diff --git a/test/built-ins/Object/S15.2.1.1_A2_T13.js b/test/built-ins/Object/S15.2.1.1_A2_T13.js
index e164bd6fc3..f3d023ab36 100644
--- a/test/built-ins/Object/S15.2.1.1_A2_T13.js
+++ b/test/built-ins/Object/S15.2.1.1_A2_T13.js
@@ -11,22 +11,7 @@ description: Calling Object function with boolean expression as argument value
 
 var obj = Object((1 === 1) && (!false));
 
-//CHECK#1
-if (obj.constructor !== Boolean) {
-  throw new Test262Error('#1: Object(expression) returns ToObject(expression)');
-}
-
-//CHECK#1.1
-if (typeof obj !== "object") {
-  throw new Test262Error('#1.1: Object(expression) returns ToObject(expression)');
-}
-
-//CHECK#2
-if (!(obj)) {
-  throw new Test262Error('#2: Object(expression) returns ToObject(expression)');
-}
-
-//CHECK#3
-if (obj === true) {
-  throw new Test262Error('#3: Object(expression) returns ToObject(expression)');
-}
+assert.sameValue(obj.constructor, Boolean, 'The value of obj.constructor is expected to equal the value of Boolean');
+assert.sameValue(typeof obj, "object", 'The value of `typeof obj` is expected to be "object"');
+assert(!!obj, 'The value of !!obj is expected to be true');
+assert.notSameValue(obj, true, 'The value of obj is not true');
diff --git a/test/built-ins/Object/S15.2.1.1_A2_T14.js b/test/built-ins/Object/S15.2.1.1_A2_T14.js
index f4f9a845e4..a1b0d276e4 100644
--- a/test/built-ins/Object/S15.2.1.1_A2_T14.js
+++ b/test/built-ins/Object/S15.2.1.1_A2_T14.js
@@ -13,17 +13,7 @@ description: >
 
 var obj = Object("" + 1);
 
-//CHECK#2
-if (obj.constructor !== String) {
-  throw new Test262Error('#2: Object(expression) returns ToObject(expression)');
-}
-
-//CHECK#3
-if (typeof obj !== "object") {
-  throw new Test262Error('#3: Object(expression) returns ToObject(expression)');
-}
-
-//CHECK#4
-if ((obj != "1") || (obj === "1")) {
-  throw new Test262Error('#4: Object(expression) returns ToObject(expression)');
-}
+assert.sameValue(obj.constructor, String, 'The value of obj.constructor is expected to equal the value of String');
+assert.sameValue(typeof obj, "object", 'The value of `typeof obj` is expected to be "object"');
+assert(obj == "1", 'The result of evaluating (obj == "1") is expected to be true');
+assert.notSameValue(obj, "1", 'The value of obj is not "1"');
diff --git a/test/built-ins/Object/S15.2.1.1_A2_T2.js b/test/built-ins/Object/S15.2.1.1_A2_T2.js
index b9d812dbeb..89b1f969c3 100644
--- a/test/built-ins/Object/S15.2.1.1_A2_T2.js
+++ b/test/built-ins/Object/S15.2.1.1_A2_T2.js
@@ -11,25 +11,12 @@ description: Calling Object function with number argument value
 
 var num = 1.1;
 
-// CHECK#1
-if (typeof num !== 'number') {
-  throw new Test262Error('#1: num = 1.1 should be Number primitive');
-}
+assert.sameValue(typeof num, 'number', 'The value of `typeof num` is expected to be "number"');
 
 var obj = Object(num);
 
-//CHECK#2
-if (typeof obj !== "object") {
-  throw new Test262Error('#2: Object(1.1) returns ToObject(1.1)');
-}
+assert.sameValue(typeof obj, "object", 'The value of `typeof obj` is expected to be "object"');
+assert.sameValue(obj.constructor, Number, 'The value of obj.constructor is expected to equal the value of Number');
 
-//CHECK#3
-if (obj.constructor !== Number) {
-  throw new Test262Error('#3: Object(1.1) returns ToObject(1.1)');
-}
-
-//CHECK#4
-if ((obj != 1.1) || (obj === 1.1)) {
-  throw new Test262Error('#4: Object(1.1) returns ToObject(1.1)');
-}
-//
+assert(obj == 1.1, 'The result of evaluating (obj == 1.1) is expected to be true');
+assert.notSameValue(obj, 1.1, 'The value of obj is not 1.1');
diff --git a/test/built-ins/Object/S15.2.1.1_A2_T3.js b/test/built-ins/Object/S15.2.1.1_A2_T3.js
index 3b476b6dec..c54eaa7c17 100644
--- a/test/built-ins/Object/S15.2.1.1_A2_T3.js
+++ b/test/built-ins/Object/S15.2.1.1_A2_T3.js
@@ -11,24 +11,11 @@ description: Calling Object function with string argument value
 
 var str = 'Luke Skywalker';
 
-// CHECK#1
-if (typeof str !== 'string') {
-  throw new Test262Error('#1: "Luke Skywalker" should be a String primitive');
-}
+assert.sameValue(typeof str, 'string', 'The value of `typeof str` is expected to be "string"');
 
 var obj = Object(str);
 
-//CHECK#2
-if (obj.constructor !== String) {
-  throw new Test262Error('#2: Object("Luke Skywalker") returns ToObject("Luke Skywalker")');
-}
-
-//CHECK#3
-if (typeof obj !== "object") {
-  throw new Test262Error('#3: Object("Luke Skywalker") returns ToObject("Luke Skywalker")');
-}
-
-//CHECK#4
-if ((obj != "Luke Skywalker") || (obj === "Luke Skywalker")) {
-  throw new Test262Error('#4: Object("Luke Skywalker") returns ToObject("Luke Skywalker")');
-}
+assert.sameValue(obj.constructor, String, 'The value of obj.constructor is expected to equal the value of String');
+assert.sameValue(typeof obj, "object", 'The value of `typeof obj` is expected to be "object"');
+assert(obj == "Luke Skywalker", 'The result of evaluating (obj == "Luke Skywalker") is expected to be true');
+assert.notSameValue(obj, "Luke Skywalker", 'The value of obj is not "Luke Skywalker"');
diff --git a/test/built-ins/Object/S15.2.1.1_A2_T4.js b/test/built-ins/Object/S15.2.1.1_A2_T4.js
index 673e74f309..85a59fdb44 100644
--- a/test/built-ins/Object/S15.2.1.1_A2_T4.js
+++ b/test/built-ins/Object/S15.2.1.1_A2_T4.js
@@ -13,14 +13,9 @@ var obj = {
   flag: true
 };
 
-//CHECK#1
-if (typeof(obj) !== 'object') {
-  throw new Test262Error('#1: obj = {flag:true} should be an Object');
-}
+assert.sameValue(typeof(obj), 'object', 'The value of `typeof(obj)` is expected to be "object"');
 
 var n_obj = Object(obj);
 
-//CHECK#2
-if ((n_obj !== obj) || (!(n_obj['flag']))) {
-  throw new Test262Error('#2: Object({flag:true}) returns ToObject({flag:true})');
-}
+assert.sameValue(n_obj, obj, 'The value of n_obj is expected to equal the value of obj');
+assert(!!n_obj['flag'], 'The value of !!n_obj["flag"] is expected to be true');
diff --git a/test/built-ins/Object/S15.2.1.1_A2_T5.js b/test/built-ins/Object/S15.2.1.1_A2_T5.js
index a147ef147a..3b57c1d092 100644
--- a/test/built-ins/Object/S15.2.1.1_A2_T5.js
+++ b/test/built-ins/Object/S15.2.1.1_A2_T5.js
@@ -11,20 +11,9 @@ description: Calling Object function with NaN argument value
 
 var num = NaN;
 
-// CHECK#1
-if (typeof num !== 'number') {
-  throw new Test262Error('#1: num = NaN should have number type');
-}
+assert.sameValue(typeof num, 'number', 'The value of `typeof num` is expected to be "number"');
 
 var obj = Object(num);
 
-//CHECK#2
-if (obj.constructor !== Number) {
-  throw new Test262Error('#2: Object(NaN) returns ToObject(NaN)');
-}
-
-//CHECK#3
-if (typeof obj !== "object") {
-  throw new Test262Error('#2: Object(NaN) returns ToObject(NaN)');
-}
-//
+assert.sameValue(obj.constructor, Number, 'The value of obj.constructor is expected to equal the value of Number');
+assert.sameValue(typeof obj, "object", 'The value of `typeof obj` is expected to be "object"');
diff --git a/test/built-ins/Object/S15.2.1.1_A2_T6.js b/test/built-ins/Object/S15.2.1.1_A2_T6.js
index 8d566e782c..d685d346bd 100644
--- a/test/built-ins/Object/S15.2.1.1_A2_T6.js
+++ b/test/built-ins/Object/S15.2.1.1_A2_T6.js
@@ -11,24 +11,11 @@ description: Calling Object function with Infinity argument value
 
 var num = Infinity;
 
-// CHECK#1
-if (typeof num !== 'number') {
-  throw new Test262Error('#1: num = Infinity should be a Number primitive');
-}
+assert.sameValue(typeof num, 'number', 'The value of `typeof num` is expected to be "number"');
 
 var obj = Object(num);
 
-//CHECK#2
-if (obj.constructor !== Number) {
-  throw new Test262Error('#2: Object(Infinity) returns ToObject(Infinity)');
-}
-
-//CHECK#3
-if (typeof obj !== "object") {
-  throw new Test262Error('#3: Object(Infinity) returns ToObject(Infinity)');
-}
-
-//CHECK#4
-if ((obj != Infinity) || (obj === Infinity)) {
-  throw new Test262Error('#4: Object(Infinity) returns ToObject(Infinity)');
-}
+assert.sameValue(obj.constructor, Number, 'The value of obj.constructor is expected to equal the value of Number');
+assert.sameValue(typeof obj, "object", 'The value of `typeof obj` is expected to be "object"');
+assert(obj == Infinity, 'The result of evaluating (obj == Infinity) is expected to be true');
+assert.notSameValue(obj, Infinity, 'The value of obj is expected to not equal ``Infinity``');
diff --git a/test/built-ins/Object/S15.2.1.1_A2_T7.js b/test/built-ins/Object/S15.2.1.1_A2_T7.js
index 7eb8e22548..87c569106a 100644
--- a/test/built-ins/Object/S15.2.1.1_A2_T7.js
+++ b/test/built-ins/Object/S15.2.1.1_A2_T7.js
@@ -11,24 +11,11 @@ description: Calling Object function with empty string argument value
 
 var str = '';
 
-// CHECK#1
-if (typeof(str) !== 'string') {
-  throw new Test262Error('#1: "" is NOT a String');
-}
+assert.sameValue(typeof(str), 'string', 'The value of `typeof(str)` is expected to be "string"');
 
 var obj = Object(str);
 
-//CHECK#2
-if (obj.constructor !== String) {
-  throw new Test262Error('#2: Object("") returns ToObject("")');
-}
-
-//CHECK#3
-if (typeof obj !== "object") {
-  throw new Test262Error('#3: Object("") returns ToObject("")');
-}
-
-//CHECK#4
-if ((obj != "") || (obj === "")) {
-  throw new Test262Error('#4: Object("") returns ToObject("")');
-}
+assert.sameValue(obj.constructor, String, 'The value of obj.constructor is expected to equal the value of String');
+assert.sameValue(typeof obj, "object", 'The value of `typeof obj` is expected to be "object"');
+assert(obj == "", 'The result of evaluating (obj == "") is expected to be true');
+assert.notSameValue(obj, "", 'The value of obj is not ""');
diff --git a/test/built-ins/Object/S15.2.1.1_A2_T8.js b/test/built-ins/Object/S15.2.1.1_A2_T8.js
index ad8428338c..20d875082d 100644
--- a/test/built-ins/Object/S15.2.1.1_A2_T8.js
+++ b/test/built-ins/Object/S15.2.1.1_A2_T8.js
@@ -13,14 +13,9 @@ var func = function() {
   return 1;
 };
 
-//CHECK#1
-if (typeof func !== 'function') {
-  throw new Test262Error('#1: func = function(){return 1;} is NOT an function');
-}
+assert.sameValue(typeof func, 'function', 'The value of `typeof func` is expected to be "function"');
 
 var n_obj = Object(func);
 
-//CHECK#2
-if ((n_obj !== func) || (n_obj() !== 1)) {
-  throw new Test262Error('#2: Object(function) returns function');
-}
+assert.sameValue(n_obj, func, 'The value of n_obj is expected to equal the value of func');
+assert.sameValue(n_obj(), 1, 'n_obj() must return 1');
diff --git a/test/built-ins/Object/S15.2.1.1_A2_T9.js b/test/built-ins/Object/S15.2.1.1_A2_T9.js
index 2757ec3608..f88904e5f7 100644
--- a/test/built-ins/Object/S15.2.1.1_A2_T9.js
+++ b/test/built-ins/Object/S15.2.1.1_A2_T9.js
@@ -10,19 +10,13 @@ description: >
     Calling Object function with function argument value. The function
     is declared
 ---*/
-
-//CHECK#1
-if (typeof func !== 'function') {
-  throw new Test262Error('#1: func = function(){return 1;} is NOT an function');
+function func() {
+  return 1;
 }
 
+assert.sameValue(typeof func, 'function', 'The value of `typeof func` is expected to be "function"');
+
 var n_obj = Object(func);
 
-//CHECK#2
-if ((n_obj !== func) || (n_obj() !== 1)) {
-  throw new Test262Error('#2: Object(function) returns function');
-}
-
-function func() {
-  return 1;
-};
+assert.sameValue(n_obj, func, 'The value of n_obj is expected to equal the value of func');
+assert.sameValue(n_obj(), 1, 'n_obj() must return 1');
diff --git a/test/built-ins/Object/S15.2.1.1_A3_T1.js b/test/built-ins/Object/S15.2.1.1_A3_T1.js
index d7921485dc..8723312bdc 100644
--- a/test/built-ins/Object/S15.2.1.1_A3_T1.js
+++ b/test/built-ins/Object/S15.2.1.1_A3_T1.js
@@ -11,17 +11,9 @@ description: Creating an object with "Object(1,2,3)"
 
 var obj = Object(1, 2, 3);
 
-//CHECK#1
-if (obj.constructor !== Number) {
-  throw new Test262Error('#1: Since Object as a function calling is the same as function calling list of arguments can appears in braces;');
-}
+assert.sameValue(obj.constructor, Number, 'The value of obj.constructor is expected to equal the value of Number');
+assert.sameValue(typeof obj, "object", 'The value of `typeof obj` is expected to be "object"');
 
-//CHECK#2
-if (typeof obj !== "object") {
-  throw new Test262Error('#2: Since Object as a function calling is the same as function calling list of arguments can appears in braces;');
-}
+assert(obj == 1, 'The result of evaluating (obj == 1) is expected to be true');
+assert.notSameValue(obj, 1, 'The value of obj is not 1');
 
-//CHECK#3
-if ((obj != 1) || (obj === 1)) {
-  throw new Test262Error('3#: Since Object as a function calling is the same as function calling list of arguments can appears in braces;');
-}
diff --git a/test/built-ins/Object/S15.2.1.1_A3_T2.js b/test/built-ins/Object/S15.2.1.1_A3_T2.js
index afc5c2cf61..18f1d85be4 100644
--- a/test/built-ins/Object/S15.2.1.1_A3_T2.js
+++ b/test/built-ins/Object/S15.2.1.1_A3_T2.js
@@ -11,12 +11,5 @@ description: Creating an object with "Object(null,2,3)"
 
 var obj = Object(null, 2, 3);
 
-//CHECK#1
-if (obj.constructor !== Object) {
-  throw new Test262Error('#1: Since Object as a function calling is the same as function calling list of arguments can appears in braces;');
-}
-
-//CHECK#2
-if (typeof obj !== "object") {
-  throw new Test262Error('#2: Since Object as a function calling is the same as function calling list of arguments can appears in braces;');
-}
+assert.sameValue(obj.constructor, Object, 'The value of obj.constructor is expected to equal the value of Object');
+assert.sameValue(typeof obj, "object", 'The value of `typeof obj` is expected to be "object"');
diff --git a/test/built-ins/Object/S15.2.1.1_A3_T3.js b/test/built-ins/Object/S15.2.1.1_A3_T3.js
index da1aef8148..2c5f6fea61 100644
--- a/test/built-ins/Object/S15.2.1.1_A3_T3.js
+++ b/test/built-ins/Object/S15.2.1.1_A3_T3.js
@@ -11,17 +11,9 @@ description: Creating an object with "Object((null,2,3),1,2)"
 
 var obj = Object((null, 2, 3), 1, 2);
 
-//CHECK#1
-if (obj.constructor !== Number) {
-  throw new Test262Error('#1: Since Object as a function calling is the same as function calling list of arguments can appears in braces;');
-}
+assert.sameValue(obj.constructor, Number, 'The value of obj.constructor is expected to equal the value of Number');
+assert.sameValue(typeof obj, "object", 'The value of `typeof obj` is expected to be "object"');
 
-//CHECK#2
-if (typeof obj !== "object") {
-  throw new Test262Error('#2: Since Object as a function calling is the same as function calling list of arguments can appears in braces;');
-}
+assert(obj == 3, 'The result of evaluating (obj == 3) is expected to be true');
+assert.notSameValue(obj, 3, 'The value of obj is not 3');
 
-//CHECK#3
-if ((obj != 3) || (obj === 3)) {
-  throw new Test262Error('3#: Since Object as a function calling is the same as function calling list of arguments can appears in braces;');
-}
diff --git a/test/built-ins/Object/S15.2.2.1_A1_T1.js b/test/built-ins/Object/S15.2.2.1_A1_T1.js
index ce30cf9ab4..e48bcc7a93 100644
--- a/test/built-ins/Object/S15.2.2.1_A1_T1.js
+++ b/test/built-ins/Object/S15.2.2.1_A1_T1.js
@@ -16,28 +16,19 @@ description: Creating new Object() and checking its properties
 
 var obj = new Object();
 
-// CHECK#0
-if (obj === undefined) {
-  throw new Test262Error('#0: new Object() return the newly created native object.');
-}
+assert.notSameValue(obj, undefined, 'The value of obj is expected to not equal ``undefined``');
+assert.sameValue(obj.constructor, Object, 'The value of obj.constructor is expected to equal the value of Object');
 
-// CHECK#1
-if (obj.constructor !== Object) {
-  throw new Test262Error('#1: new Object() create a new native ECMAScript object');
-}
+assert(
+  !!Object.prototype.isPrototypeOf(obj),
+  'The value of !!Object.prototype.isPrototypeOf(obj) is expected to be true'
+);
 
-// CHECK#2
-if (!(Object.prototype.isPrototypeOf(obj))) {
-  throw new Test262Error('#2: when new Object() calls the [[Prototype]] property of the newly constructed object is set to the Object prototype object.');
-}
-
-// CHECK#3
 var to_string_result = '[object ' + 'Object' + ']';
-if (obj.toString() !== to_string_result) {
-  throw new Test262Error('#3: when new Object() calls the [[Class]] property of the newly constructed object is set to "Object".');
-}
+assert.sameValue(obj.toString(), to_string_result, 'obj.toString() returns to_string_result');
 
-// CHECK#4
-if (obj.valueOf().toString() !== to_string_result.toString()) {
-  throw new Test262Error('#4: when new Object() calls the newly constructed object has no [[Value]] property.');
-}
+assert.sameValue(
+  obj.valueOf().toString(),
+  to_string_result.toString(),
+  'obj.valueOf().toString() must return the same value returned by to_string_result.toString()'
+);
diff --git a/test/built-ins/Object/S15.2.2.1_A1_T2.js b/test/built-ins/Object/S15.2.2.1_A1_T2.js
index 27744917ff..7d2f16dcd6 100644
--- a/test/built-ins/Object/S15.2.2.1_A1_T2.js
+++ b/test/built-ins/Object/S15.2.2.1_A1_T2.js
@@ -17,28 +17,19 @@ description: Creating new Object(void 0) and checking its properties
 //var foo = void 0;
 var obj = new Object(void 0);
 
-// CHECK#0
-if (obj === undefined) {
-  throw new Test262Error('#0: new Object(undefined) return the newly created native object.');
-}
+assert.notSameValue(obj, undefined, 'The value of obj is expected to not equal ``undefined``');
+assert.sameValue(obj.constructor, Object, 'The value of obj.constructor is expected to equal the value of Object');
 
-// CHECK#1
-if (obj.constructor !== Object) {
-  throw new Test262Error('#1: new Object(undefined) create a new native ECMAScript object');
-}
+assert(
+  !!Object.prototype.isPrototypeOf(obj),
+  'The value of !!Object.prototype.isPrototypeOf(obj) is expected to be true'
+);
 
-// CHECK#2
-if (!(Object.prototype.isPrototypeOf(obj))) {
-  throw new Test262Error('#2: when new Object(undefined) calls the [[Prototype]] property of the newly constructed object is set to the Object prototype object.');
-}
-
-// CHECK#3
 var to_string_result = '[object ' + 'Object' + ']';
-if (obj.toString() !== to_string_result) {
-  throw new Test262Error('#3: when new Object(undefined) calls the [[Class]] property of the newly constructed object is set to "Object".');
-}
+assert.sameValue(obj.toString(), to_string_result, 'obj.toString() returns to_string_result');
 
-// CHECK#4
-if (obj.valueOf().toString() !== to_string_result.toString()) {
-  throw new Test262Error('#4: when new Object(undefined) calls the newly constructed object has no [[Value]] property.');
-}
+assert.sameValue(
+  obj.valueOf().toString(),
+  to_string_result.toString(),
+  'obj.valueOf().toString() must return the same value returned by to_string_result.toString()'
+);
diff --git a/test/built-ins/Object/S15.2.2.1_A1_T3.js b/test/built-ins/Object/S15.2.2.1_A1_T3.js
index 847e93b180..1c2bfb061a 100644
--- a/test/built-ins/Object/S15.2.2.1_A1_T3.js
+++ b/test/built-ins/Object/S15.2.2.1_A1_T3.js
@@ -16,28 +16,19 @@ description: Creating new Object(null) and checking its properties
 
 var obj = new Object(null);
 
-// CHECK#0
-if (obj === undefined) {
-  throw new Test262Error('#0: new Object(null) return the newly created native object.');
-}
+assert.notSameValue(obj, undefined, 'The value of obj is expected to not equal ``undefined``');
+assert.sameValue(obj.constructor, Object, 'The value of obj.constructor is expected to equal the value of Object');
 
-// CHECK#1
-if (obj.constructor !== Object) {
-  throw new Test262Error('#1: new Object(null) create a new native ECMAScript object');
-}
+assert(
+  !!Object.prototype.isPrototypeOf(obj),
+  'The value of !!Object.prototype.isPrototypeOf(obj) is expected to be true'
+);
 
-// CHECK#2
-if (!(Object.prototype.isPrototypeOf(obj))) {
-  throw new Test262Error('#2: when new Object(null) calls the [[Prototype]] property of the newly constructed object is set to the Object prototype object.');
-}
-
-// CHECK#3
 var to_string_result = '[object ' + 'Object' + ']';
-if (obj.toString() !== to_string_result) {
-  throw new Test262Error('#3: when new Object(null) calls the [[Class]] property of the newly constructed object is set to "Object".');
-}
+assert.sameValue(obj.toString(), to_string_result, 'obj.toString() returns to_string_result');
 
-// CHECK#4
-if (obj.valueOf().toString() !== to_string_result.toString()) {
-  throw new Test262Error('#4: when new Object(null) calls the newly constructed object has no [[Value]] property.');
-}
+assert.sameValue(
+  obj.valueOf().toString(),
+  to_string_result.toString(),
+  'obj.valueOf().toString() must return the same value returned by to_string_result.toString()'
+);
diff --git a/test/built-ins/Object/S15.2.2.1_A1_T4.js b/test/built-ins/Object/S15.2.2.1_A1_T4.js
index 8b0cfab4b9..a1e4aba13e 100644
--- a/test/built-ins/Object/S15.2.2.1_A1_T4.js
+++ b/test/built-ins/Object/S15.2.2.1_A1_T4.js
@@ -16,28 +16,19 @@ description: Creating new Object(undefined) and checking its properties
 
 var obj = new Object(undefined);
 
-// CHECK#0
-if (obj === undefined) {
-  throw new Test262Error('#0: new Object(undefined) return the newly created native object.');
-}
+assert.notSameValue(obj, undefined, 'The value of obj is expected to not equal ``undefined``');
+assert.sameValue(obj.constructor, Object, 'The value of obj.constructor is expected to equal the value of Object');
 
-// CHECK#1
-if (obj.constructor !== Object) {
-  throw new Test262Error('#1: new Object(undefined) create a new native ECMAScript object');
-}
+assert(
+  !!Object.prototype.isPrototypeOf(obj),
+  'The value of !!Object.prototype.isPrototypeOf(obj) is expected to be true'
+);
 
-// CHECK#2
-if (!(Object.prototype.isPrototypeOf(obj))) {
-  throw new Test262Error('#2: when new Object(undefined) calls the [[Prototype]] property of the newly constructed object is set to the Object prototype object.');
-}
-
-// CHECK#3
 var to_string_result = '[object ' + 'Object' + ']';
-if (obj.toString() !== to_string_result) {
-  throw new Test262Error('#3: when new Object(undefined) calls the [[Class]] property of the newly constructed object is set to "Object".');
-}
+assert.sameValue(obj.toString(), to_string_result, 'obj.toString() returns to_string_result');
 
-// CHECK#4
-if (obj.valueOf().toString() !== to_string_result.toString()) {
-  throw new Test262Error('#4: when new Object(undefined) calls the newly constructed object has no [[Value]] property.');
-}
+assert.sameValue(
+  obj.valueOf().toString(),
+  to_string_result.toString(),
+  'obj.valueOf().toString() must return the same value returned by to_string_result.toString()'
+);
diff --git a/test/built-ins/Object/S15.2.2.1_A1_T5.js b/test/built-ins/Object/S15.2.2.1_A1_T5.js
index 294b220995..2c699677b0 100644
--- a/test/built-ins/Object/S15.2.2.1_A1_T5.js
+++ b/test/built-ins/Object/S15.2.2.1_A1_T5.js
@@ -18,30 +18,21 @@ description: >
 
 var obj = new Object(x);
 
-// CHECK#0
-if (obj === undefined) {
-  throw new Test262Error('#0: new Object(undefined) return the newly created native object.');
-}
+assert.notSameValue(obj, undefined, 'The value of obj is expected to not equal ``undefined``');
+assert.sameValue(obj.constructor, Object, 'The value of obj.constructor is expected to equal the value of Object');
 
-// CHECK#1
-if (obj.constructor !== Object) {
-  throw new Test262Error('#1: new Object(undefined) create a new native ECMAScript object');
-}
+assert(
+  !!Object.prototype.isPrototypeOf(obj),
+  'The value of !!Object.prototype.isPrototypeOf(obj) is expected to be true'
+);
 
-// CHECK#2
-if (!(Object.prototype.isPrototypeOf(obj))) {
-  throw new Test262Error('#2: when new Object(undefined) calls the [[Prototype]] property of the newly constructed object is set to the Object prototype object.');
-}
-
-// CHECK#3
 var to_string_result = '[object ' + 'Object' + ']';
-if (obj.toString() !== to_string_result) {
-  throw new Test262Error('#3: when new Object(undefined) calls the [[Class]] property of the newly constructed object is set to "Object".');
-}
+assert.sameValue(obj.toString(), to_string_result, 'obj.toString() returns to_string_result');
 
-// CHECK#4
-if (obj.valueOf().toString() !== to_string_result.toString()) {
-  throw new Test262Error('#4: when new Object(undefined) calls the newly constructed object has no [[Value]] property.');
-}
+assert.sameValue(
+  obj.valueOf().toString(),
+  to_string_result.toString(),
+  'obj.valueOf().toString() must return the same value returned by to_string_result.toString()'
+);
 
 var x;
diff --git a/test/built-ins/Object/S15.2.2.1_A2_T1.js b/test/built-ins/Object/S15.2.2.1_A2_T1.js
index c6593fe6da..9482ac7aa1 100644
--- a/test/built-ins/Object/S15.2.2.1_A2_T1.js
+++ b/test/built-ins/Object/S15.2.2.1_A2_T1.js
@@ -15,12 +15,5 @@ var obj = {
 
 var n_obj = new Object(obj);
 
-//CHECK#1
-if (n_obj !== obj) {
-  throw new Test262Error('#1: When the Object constructor is called and if the value is an Object simply value returns.');
-}
-
-//CHECK#2
-if (n_obj['prop'] !== 1) {
-  throw new Test262Error('#2: When the Object constructor is called and if the value is an Object simply value returns.');
-}
+assert.sameValue(n_obj, obj, 'The value of n_obj is expected to equal the value of obj');
+assert.sameValue(n_obj['prop'], 1, 'The value of n_obj["prop"] is expected to be 1');
diff --git a/test/built-ins/Object/S15.2.2.1_A2_T2.js b/test/built-ins/Object/S15.2.2.1_A2_T2.js
index 16052dd49a..0fe7b97e7e 100644
--- a/test/built-ins/Object/S15.2.2.1_A2_T2.js
+++ b/test/built-ins/Object/S15.2.2.1_A2_T2.js
@@ -15,13 +15,5 @@ var func = function() {
 
 var n_obj = new Object(func);
 
-//CHECK#1
-if (n_obj !== func) {
-  throw new Test262Error('#1: When the Object constructor is called and if the value is an Object simply value returns');
-}
-
-//CHECK#2
-if (n_obj() !== 1) {
-  throw new Test262Error('When the Object constructor is called and if the value is an Object simply value returns');
-}
-//
+assert.sameValue(n_obj, func, 'The value of n_obj is expected to equal the value of func');
+assert.sameValue(n_obj(), 1, 'n_obj() must return 1');
diff --git a/test/built-ins/Object/S15.2.2.1_A2_T3.js b/test/built-ins/Object/S15.2.2.1_A2_T3.js
index 5102962688..867a091b40 100644
--- a/test/built-ins/Object/S15.2.2.1_A2_T3.js
+++ b/test/built-ins/Object/S15.2.2.1_A2_T3.js
@@ -15,12 +15,5 @@ var n_obj = new Object(arr);
 
 arr.push(4);
 
-//CHECK#1
-if (n_obj !== arr) {
-  throw new Test262Error('#1: When the Object constructor is called and if the value is an Object simply value returns.');
-}
-
-//CHECK#2
-if (n_obj[3] !== 4) {
-  throw new Test262Error('#2: When the Object constructor is called and if the value is an Object simply value returns.');
-}
+assert.sameValue(n_obj, arr, 'The value of n_obj is expected to equal the value of arr');
+assert.sameValue(n_obj[3], 4, 'The value of n_obj[3] is expected to be 4');
diff --git a/test/built-ins/Object/S15.2.2.1_A2_T5.js b/test/built-ins/Object/S15.2.2.1_A2_T5.js
index 1bf78b9028..70bfd0e11f 100644
--- a/test/built-ins/Object/S15.2.2.1_A2_T5.js
+++ b/test/built-ins/Object/S15.2.2.1_A2_T5.js
@@ -13,12 +13,6 @@ var obj = new Date(1978, 3);
 
 var n_obj = new Object(obj);
 
-//CHECK#1
-if (n_obj !== obj) {
-  throw new Test262Error('#1: When the Object constructor is called and if the value is an Object simply value returns.');
-}
-
-//CHECK#2
-if ((n_obj.getFullYear() !== 1978) || (n_obj.getMonth() !== 3)) {
-  throw new Test262Error('#2: When the Object constructor is called and if the value is an Object simply value returns.');
-}
+assert.sameValue(n_obj, obj, 'The value of n_obj is expected to equal the value of obj');
+assert.sameValue(n_obj.getFullYear(), 1978, 'n_obj.getFullYear() must return 1978');
+assert.sameValue(n_obj.getMonth(), 3, 'n_obj.getMonth() must return 3');
diff --git a/test/built-ins/Object/S15.2.2.1_A2_T6.js b/test/built-ins/Object/S15.2.2.1_A2_T6.js
index 211032c595..81c5d5503c 100644
--- a/test/built-ins/Object/S15.2.2.1_A2_T6.js
+++ b/test/built-ins/Object/S15.2.2.1_A2_T6.js
@@ -11,16 +11,9 @@ description: The value is a declared function
 
 var n_obj = new Object(func);
 
-//CHECK#1
-if (n_obj !== func) {
-  throw new Test262Error('#1: When the Object constructor is called and if the value is an Object simply value returns');
-}
-
-//CHECK#2
-if (n_obj() !== 1) {
-  throw new Test262Error('When the Object constructor is called and if the value is an Object simply value returns');
-}
+assert.sameValue(n_obj, func, 'The value of n_obj is expected to equal the value of func');
+assert.sameValue(n_obj(), 1, 'n_obj() must return 1');
 
 function func() {
   return 1;
-};
+}
diff --git a/test/built-ins/Object/S15.2.2.1_A2_T7.js b/test/built-ins/Object/S15.2.2.1_A2_T7.js
index dd1675e74c..d931901d08 100644
--- a/test/built-ins/Object/S15.2.2.1_A2_T7.js
+++ b/test/built-ins/Object/S15.2.2.1_A2_T7.js
@@ -8,27 +8,17 @@ info: |
 es5id: 15.2.2.1_A2_T7
 description: The value is a function declaration
 ---*/
-
-//CHECK#0
-if (typeof func !== 'undefined') {
-  throw new Test262Error('#0: function expression can\'t be declarated');
-}
+assert.sameValue(typeof func, 'undefined', 'The value of `typeof func` is expected to be "undefined"');
 
 var n_obj = new Object(function func() {
   return 1;
 });
 
-//CHECK#1
-if (n_obj.constructor !== Function) {
-  throw new Test262Error('#1: When the Object constructor is called and if the value is an Object simply value returns');
-}
+assert.sameValue(
+  n_obj.constructor,
+  Function,
+  'The value of n_obj.constructor is expected to equal the value of Function'
+);
 
-//CHECK#2
-if (n_obj() !== 1) {
-  throw new Test262Error('#2: When the Object constructor is called and if the value is an Object simply value returns');
-}
-
-//CHECK#3
-if (typeof func !== 'undefined') {
-  throw new Test262Error('#3: function expression can\'t be declarated');
-}
+assert.sameValue(n_obj(), 1, 'n_obj() must return 1');
+assert.sameValue(typeof func, 'undefined', 'The value of `typeof func` is expected to be "undefined"');
diff --git a/test/built-ins/Object/S15.2.2.1_A3_T1.js b/test/built-ins/Object/S15.2.2.1_A3_T1.js
index 54aa6c1daf..55a075dd4b 100644
--- a/test/built-ins/Object/S15.2.2.1_A3_T1.js
+++ b/test/built-ins/Object/S15.2.2.1_A3_T1.js
@@ -11,30 +11,12 @@ description: Argument value is a nonempty string
 
 var str = 'Obi-Wan Kenobi';
 
-//CHECK#1
-if (typeof str !== 'string') {
-  throw new Test262Error('#1: "Obi-Wan Kenobi" is NOT a String');
-}
+assert.sameValue(typeof str, 'string', 'The value of `typeof str` is expected to be "string"');
 
 
 var n_obj = new Object(str);
 
-//CHECK#2
-if (n_obj.constructor !== String) {
-  throw new Test262Error('#2: When the Object constructor is called with String argument return ToObject(string)');
-}
-
-//CHECK#3
-if (typeof n_obj !== 'object') {
-  throw new Test262Error('#3: When the Object constructor is called with String argument return ToObject(string)');
-}
-
-//CHECK#4
-if (n_obj != str) {
-  throw new Test262Error('#4: When the Object constructor is called with String argument return ToObject(string)');
-}
-
-//CHECK#5
-if (n_obj === str) {
-  throw new Test262Error('#5: When the Object constructor is called with String argument return ToObject(string)');
-}
+assert.sameValue(n_obj.constructor, String, 'The value of n_obj.constructor is expected to equal the value of String');
+assert.sameValue(typeof n_obj, 'object', 'The value of `typeof n_obj` is expected to be "object"');
+assert(n_obj == str, 'The result of evaluating (n_obj == str) is expected to be true');
+assert.notSameValue(n_obj, str, 'The value of n_obj is expected to not equal the value of `str`');
diff --git a/test/built-ins/Object/S15.2.2.1_A3_T2.js b/test/built-ins/Object/S15.2.2.1_A3_T2.js
index 3df6985a5a..6fc6c8baed 100644
--- a/test/built-ins/Object/S15.2.2.1_A3_T2.js
+++ b/test/built-ins/Object/S15.2.2.1_A3_T2.js
@@ -11,29 +11,11 @@ description: Argument value is an empty string
 
 var str = '';
 
-//CHECK#1
-if (typeof str !== 'string') {
-  throw new Test262Error('#1: "" is NOT a String');
-}
+assert.sameValue(typeof str, 'string', 'The value of `typeof str` is expected to be "string"');
 
 var n_obj = new Object(str);
 
-//CHECK#2
-if (n_obj.constructor !== String) {
-  throw new Test262Error('#2: When the Object constructor is called with String argument return ToObject(string)');
-}
-
-//CHECK#3
-if (typeof n_obj !== 'object') {
-  throw new Test262Error('#3: When the Object constructor is called with String argument return ToObject(string)');
-}
-
-//CHECK#4
-if (n_obj != str) {
-  throw new Test262Error('#4: When the Object constructor is called with String argument return ToObject(string)');
-}
-
-//CHECK#5
-if (n_obj === str) {
-  throw new Test262Error('#5: When the Object constructor is called with String argument return ToObject(string)');
-}
+assert.sameValue(n_obj.constructor, String, 'The value of n_obj.constructor is expected to equal the value of String');
+assert.sameValue(typeof n_obj, 'object', 'The value of `typeof n_obj` is expected to be "object"');
+assert(n_obj == str, 'The result of evaluating (n_obj == str) is expected to be true');
+assert.notSameValue(n_obj, str, 'The value of n_obj is expected to not equal the value of `str`');
diff --git a/test/built-ins/Object/S15.2.2.1_A3_T3.js b/test/built-ins/Object/S15.2.2.1_A3_T3.js
index f476237c96..436b6ea069 100644
--- a/test/built-ins/Object/S15.2.2.1_A3_T3.js
+++ b/test/built-ins/Object/S15.2.2.1_A3_T3.js
@@ -11,22 +11,7 @@ description: Argument value is sum of empty string and number
 
 var n_obj = new Object("" + 1);
 
-//CHECK#2
-if (n_obj.constructor !== String) {
-  throw new Test262Error('#2: When the Object constructor is called with String argument return ToObject(string)');
-}
-
-//CHECK#3
-if (typeof n_obj !== 'object') {
-  throw new Test262Error('#3: When the Object constructor is called with String argument return ToObject(string)');
-}
-
-//CHECK#4
-if (n_obj != "1") {
-  throw new Test262Error('#4: When the Object constructor is called with String argument return ToObject(string)');
-}
-
-//CHECK#5
-if (n_obj === "1") {
-  throw new Test262Error('#5: When the Object constructor is called with String argument return ToObject(string)');
-}
+assert.sameValue(n_obj.constructor, String, 'The value of n_obj.constructor is expected to equal the value of String');
+assert.sameValue(typeof n_obj, 'object', 'The value of `typeof n_obj` is expected to be "object"');
+assert(n_obj == "1", 'The result of evaluating (n_obj == "1") is expected to be true');
+assert.notSameValue(n_obj, "1", 'The value of n_obj is not "1"');
diff --git a/test/built-ins/Object/S15.2.2.1_A4_T1.js b/test/built-ins/Object/S15.2.2.1_A4_T1.js
index 147e0676b1..1a713921e9 100644
--- a/test/built-ins/Object/S15.2.2.1_A4_T1.js
+++ b/test/built-ins/Object/S15.2.2.1_A4_T1.js
@@ -11,29 +11,16 @@ description: Argument value is "true"
 
 var bool = true;
 
-//CHECK#1
-if (typeof bool !== 'boolean') {
-  throw new Test262Error('#1: true is NOT a boolean');
-}
+assert.sameValue(typeof bool, 'boolean', 'The value of `typeof bool` is expected to be "boolean"');
 
 var n_obj = new Object(bool);
 
-//CHECK#2
-if (n_obj.constructor !== Boolean) {
-  throw new Test262Error('#2: When the Object constructor is called with Boolean argument return ToObject(boolean)');
-}
+assert.sameValue(
+  n_obj.constructor,
+  Boolean,
+  'The value of n_obj.constructor is expected to equal the value of Boolean'
+);
 
-//CHECK#3
-if (typeof n_obj !== 'object') {
-  throw new Test262Error('#3: When the Object constructor is called with Boolean argument return ToObject(boolean)');
-}
-
-//CHECK#4
-if (n_obj != bool) {
-  throw new Test262Error('#4: When the Object constructor is called with Boolean argument return ToObject(boolean)');
-}
-
-//CHECK#5
-if (n_obj === bool) {
-  throw new Test262Error('#5: When the Object constructor is called with Boolean argument return ToObject(boolean)');
-}
+assert.sameValue(typeof n_obj, 'object', 'The value of `typeof n_obj` is expected to be "object"');
+assert(n_obj == bool, 'The result of evaluating (n_obj == bool) is expected to be true');
+assert.notSameValue(n_obj, bool, 'The value of n_obj is expected to not equal the value of `bool`');
diff --git a/test/built-ins/Object/S15.2.2.1_A4_T2.js b/test/built-ins/Object/S15.2.2.1_A4_T2.js
index 0e0676006a..ee3bf3dfdf 100644
--- a/test/built-ins/Object/S15.2.2.1_A4_T2.js
+++ b/test/built-ins/Object/S15.2.2.1_A4_T2.js
@@ -11,29 +11,16 @@ description: Argument value is "false"
 
 var bool = false;
 
-//CHECK#1
-if (typeof bool !== 'boolean') {
-  throw new Test262Error('#1: false is NOT a boolean');
-}
+assert.sameValue(typeof bool, 'boolean', 'The value of `typeof bool` is expected to be "boolean"');
 
 var n_obj = new Object(bool);
 
-//CHECK#2
-if (n_obj.constructor !== Boolean) {
-  throw new Test262Error('#2: When the Object constructor is called with Boolean argument return ToObject(boolean)');
-}
+assert.sameValue(
+  n_obj.constructor,
+  Boolean,
+  'The value of n_obj.constructor is expected to equal the value of Boolean'
+);
 
-//CHECK#3
-if (typeof n_obj !== 'object') {
-  throw new Test262Error('#3: When the Object constructor is called with Boolean argument return ToObject(boolean)');
-}
-
-//CHECK#4
-if (n_obj != bool) {
-  throw new Test262Error('#4: When the Object constructor is called with Boolean argument return ToObject(boolean)');
-}
-
-//CHECK#5
-if (n_obj === bool) {
-  throw new Test262Error('#5: When the Object constructor is called with Boolean argument return ToObject(boolean)');
-}
+assert.sameValue(typeof n_obj, 'object', 'The value of `typeof n_obj` is expected to be "object"');
+assert(n_obj == bool, 'The result of evaluating (n_obj == bool) is expected to be true');
+assert.notSameValue(n_obj, bool, 'The value of n_obj is expected to not equal the value of `bool`');
diff --git a/test/built-ins/Object/S15.2.2.1_A4_T3.js b/test/built-ins/Object/S15.2.2.1_A4_T3.js
index 3769cfc0ae..bee0284dec 100644
--- a/test/built-ins/Object/S15.2.2.1_A4_T3.js
+++ b/test/built-ins/Object/S15.2.2.1_A4_T3.js
@@ -11,22 +11,12 @@ description: Argument value is boolean expression
 
 var n_obj = new Object((1 === 1) && !(false));
 
-//CHECK#2
-if (n_obj.constructor !== Boolean) {
-  throw new Test262Error('#2: When the Object constructor is called with Boolean argument return ToObject(boolean)');
-}
+assert.sameValue(
+  n_obj.constructor,
+  Boolean,
+  'The value of n_obj.constructor is expected to equal the value of Boolean'
+);
 
-//CHECK#3
-if (typeof n_obj !== 'object') {
-  throw new Test262Error('#3: When the Object constructor is called with Boolean argument return ToObject(boolean)');
-}
-
-//CHECK#4
-if (n_obj != true) {
-  throw new Test262Error('#4: When the Object constructor is called with Boolean argument return ToObject(boolean)');
-}
-
-//CHECK#5
-if (n_obj === true) {
-  throw new Test262Error('#5: When the Object constructor is called with Boolean argument return ToObject(boolean)');
-}
+assert.sameValue(typeof n_obj, 'object', 'The value of `typeof n_obj` is expected to be "object"');
+assert(n_obj == true, 'The result of evaluating (n_obj == true) is expected to be true');
+assert.notSameValue(n_obj, true, 'The value of n_obj is not true');
diff --git a/test/built-ins/Object/S15.2.2.1_A5_T1.js b/test/built-ins/Object/S15.2.2.1_A5_T1.js
index da2b630bfa..4951823f14 100644
--- a/test/built-ins/Object/S15.2.2.1_A5_T1.js
+++ b/test/built-ins/Object/S15.2.2.1_A5_T1.js
@@ -11,29 +11,11 @@ description: Argument value is any number
 
 var num = 1.0;
 
-//CHECK#1
-if (typeof num !== 'number') {
-  throw new Test262Error('#1: 1.0 is NOT a number');
-}
+assert.sameValue(typeof num, 'number', 'The value of `typeof num` is expected to be "number"');
 
 var n_obj = new Object(num);
 
-//CHECK#2
-if (n_obj.constructor !== Number) {
-  throw new Test262Error('#2: When the Object constructor is called with Number argument return ToObject(number)');
-}
-
-//CHECK#3
-if (typeof n_obj !== 'object') {
-  throw new Test262Error('#3: When the Object constructor is called with Number argument return ToObject(number)');
-}
-
-//CHECK#4
-if (n_obj != num) {
-  throw new Test262Error('#4: When the Object constructor is called with Number argument return ToObject(number)');
-}
-
-//CHECK#5
-if (n_obj === num) {
-  throw new Test262Error('#5: When the Object constructor is called with Number argument return ToObject(number)');
-}
+assert.sameValue(n_obj.constructor, Number, 'The value of n_obj.constructor is expected to equal the value of Number');
+assert.sameValue(typeof n_obj, 'object', 'The value of `typeof n_obj` is expected to be "object"');
+assert(n_obj == num, 'The result of evaluating (n_obj == num) is expected to be true');
+assert.notSameValue(n_obj, num, 'The value of n_obj is expected to not equal the value of `num`');
diff --git a/test/built-ins/Object/S15.2.2.1_A5_T2.js b/test/built-ins/Object/S15.2.2.1_A5_T2.js
index 2e5e2fa924..5e70256cfe 100644
--- a/test/built-ins/Object/S15.2.2.1_A5_T2.js
+++ b/test/built-ins/Object/S15.2.2.1_A5_T2.js
@@ -11,19 +11,9 @@ description: Argument value is NaN
 
 var num = NaN;
 
-//CHECK#1
-if (typeof num !== 'number') {
-  throw new Test262Error('#1: NaN is NOT a number');
-}
+assert.sameValue(typeof num, 'number', 'The value of `typeof num` is expected to be "number"');
 
 var n_obj = new Object(num);
 
-//CHECK#2
-if (n_obj.constructor !== Number) {
-  throw new Test262Error('#2: When the Object constructor is called with Number argument return ToObject(number)');
-}
-
-//CHECK#3
-if (typeof n_obj !== 'object') {
-  throw new Test262Error('#3: When the Object constructor is called with Number argument return ToObject(number)');
-}
+assert.sameValue(n_obj.constructor, Number, 'The value of n_obj.constructor is expected to equal the value of Number');
+assert.sameValue(typeof n_obj, 'object', 'The value of `typeof n_obj` is expected to be "object"');
diff --git a/test/built-ins/Object/S15.2.2.1_A5_T3.js b/test/built-ins/Object/S15.2.2.1_A5_T3.js
index dd001ce384..db39aa271f 100644
--- a/test/built-ins/Object/S15.2.2.1_A5_T3.js
+++ b/test/built-ins/Object/S15.2.2.1_A5_T3.js
@@ -11,29 +11,11 @@ description: Argument value is Infinity
 
 var num = Infinity;
 
-//CHECK#1
-if (typeof num !== 'number') {
-  throw new Test262Error('#1: Infinity is NOT a number');
-}
+assert.sameValue(typeof num, 'number', 'The value of `typeof num` is expected to be "number"');
 
 var n_obj = new Object(num);
 
-//CHECK#2
-if (n_obj.constructor !== Number) {
-  throw new Test262Error('#2: When the Object constructor is called with Number argument return ToObject(number)');
-}
-
-//CHECK#3
-if (typeof n_obj !== 'object') {
-  throw new Test262Error('#3: When the Object constructor is called with Number argument return ToObject(number)');
-}
-
-//CHECK#4
-if (n_obj != num) {
-  throw new Test262Error('#4: When the Object constructor is called with Number argument return ToObject(number)');
-}
-
-//CHECK#5
-if (n_obj === num) {
-  throw new Test262Error('#5: When the Object constructor is called with Number argument return ToObject(number)');
-}
+assert.sameValue(n_obj.constructor, Number, 'The value of n_obj.constructor is expected to equal the value of Number');
+assert.sameValue(typeof n_obj, 'object', 'The value of `typeof n_obj` is expected to be "object"');
+assert(n_obj == num, 'The result of evaluating (n_obj == num) is expected to be true');
+assert.notSameValue(n_obj, num, 'The value of n_obj is expected to not equal the value of `num`');
diff --git a/test/built-ins/Object/S15.2.2.1_A5_T4.js b/test/built-ins/Object/S15.2.2.1_A5_T4.js
index 1abad02825..e4bf8628fe 100644
--- a/test/built-ins/Object/S15.2.2.1_A5_T4.js
+++ b/test/built-ins/Object/S15.2.2.1_A5_T4.js
@@ -13,22 +13,7 @@ var n_obj = new Object(2 * ([].length + {
   q: 1
 }["q"]));
 
-//CHECK#2
-if (n_obj.constructor !== Number) {
-  throw new Test262Error('#2: When the Object constructor is called with Number argument return ToObject(number)');
-}
-
-//CHECK#3
-if (typeof n_obj !== 'object') {
-  throw new Test262Error('#3: When the Object constructor is called with Number argument return ToObject(number)');
-}
-
-//CHECK#4
-if (n_obj != 2) {
-  throw new Test262Error('#4: When the Object constructor is called with Number argument return ToObject(number)');
-}
-
-//CHECK#5
-if (n_obj === 2) {
-  throw new Test262Error('#5: When the Object constructor is called with Number argument return ToObject(number)');
-}
+assert.sameValue(n_obj.constructor, Number, 'The value of n_obj.constructor is expected to equal the value of Number');
+assert.sameValue(typeof n_obj, 'object', 'The value of `typeof n_obj` is expected to be "object"');
+assert(n_obj == 2, 'The result of evaluating (n_obj == 2) is expected to be true');
+assert.notSameValue(n_obj, 2, 'The value of n_obj is not 2');
diff --git a/test/built-ins/Object/S15.2.2.1_A6_T1.js b/test/built-ins/Object/S15.2.2.1_A6_T1.js
index 8e68d11934..2dd43c0000 100644
--- a/test/built-ins/Object/S15.2.2.1_A6_T1.js
+++ b/test/built-ins/Object/S15.2.2.1_A6_T1.js
@@ -11,17 +11,8 @@ description: Creating an object with "new Object(1,2,3)"
 
 var obj = new Object(1, 2, 3);
 
-//CHECK#1
-if (obj.constructor !== Number) {
-  throw new Test262Error('#1: Since Object as a function calling is the same as function calling list of arguments can appears in braces;');
-}
+assert.sameValue(obj.constructor, Number, 'The value of obj.constructor is expected to equal the value of Number');
+assert.sameValue(typeof obj, "object", 'The value of `typeof obj` is expected to be "object"');
+assert(obj == 1, 'The result of evaluating (obj == 1) is expected to be true');
+assert.notSameValue(obj, 1, 'The value of obj is not 1');
 
-//CHECK#2
-if (typeof obj !== "object") {
-  throw new Test262Error('#2: Since Object as a function calling is the same as function calling list of arguments can appears in braces;');
-}
-
-//CHECK#3
-if ((obj != 1) || (obj === 1)) {
-  throw new Test262Error('3#: Since Object as a function calling is the same as function calling list of arguments can appears in braces;');
-}
diff --git a/test/built-ins/Object/S15.2.2.1_A6_T2.js b/test/built-ins/Object/S15.2.2.1_A6_T2.js
index f98242ba78..1b88acfcca 100644
--- a/test/built-ins/Object/S15.2.2.1_A6_T2.js
+++ b/test/built-ins/Object/S15.2.2.1_A6_T2.js
@@ -11,12 +11,5 @@ description: Creating an object with "new Object(null,2,3)"
 
 var obj = new Object(null, 2, 3);
 
-//CHECK#1
-if (obj.constructor !== Object) {
-  throw new Test262Error('#1: Since Object as a function calling is the same as function calling list of arguments can appears in braces;');
-}
-
-//CHECK#2
-if (typeof obj !== "object") {
-  throw new Test262Error('#2: Since Object as a function calling is the same as function calling list of arguments can appears in braces;');
-}
+assert.sameValue(obj.constructor, Object, 'The value of obj.constructor is expected to equal the value of Object');
+assert.sameValue(typeof obj, "object", 'The value of `typeof obj` is expected to be "object"');
diff --git a/test/built-ins/Object/S15.2.2.1_A6_T3.js b/test/built-ins/Object/S15.2.2.1_A6_T3.js
index 8cf2e36893..24d3e41ec2 100644
--- a/test/built-ins/Object/S15.2.2.1_A6_T3.js
+++ b/test/built-ins/Object/S15.2.2.1_A6_T3.js
@@ -11,17 +11,7 @@ description: Creating an object with "new Object((null,2,3),2,3)"
 
 var obj = new Object((null, 2, 3), 1, 2);
 
-//CHECK#1
-if (obj.constructor !== Number) {
-  throw new Test262Error('#1: Since Object as a function calling is the same as function calling list of arguments can appears in braces;');
-}
-
-//CHECK#2
-if (typeof obj !== "object") {
-  throw new Test262Error('#2: Since Object as a function calling is the same as function calling list of arguments can appears in braces;');
-}
-
-//CHECK#3
-if ((obj != 3) || (obj === 3)) {
-  throw new Test262Error('3#: Since Object as a function calling is the same as function calling list of arguments can appears in braces;');
-}
+assert.sameValue(obj.constructor, Number, 'The value of obj.constructor is expected to equal the value of Number');
+assert.sameValue(typeof obj, "object", 'The value of `typeof obj` is expected to be "object"');
+assert(obj == 3, 'The result of evaluating (obj == 3) is expected to be true');
+assert.notSameValue(obj, 3, 'The value of obj is not 3');
diff --git a/test/built-ins/Object/S15.2.3_A1.js b/test/built-ins/Object/S15.2.3_A1.js
index d95164824e..3a32528d5b 100644
--- a/test/built-ins/Object/S15.2.3_A1.js
+++ b/test/built-ins/Object/S15.2.3_A1.js
@@ -6,7 +6,7 @@ info: The Object constructor has the property "prototype"
 es5id: 15.2.3_A1
 description: Checking existence of the property "prototype"
 ---*/
-
-if (!Object.hasOwnProperty("prototype")) {
-  throw new Test262Error('#1: The Object constructor has the property "prototype"');
-}
+assert(
+  !!Object.hasOwnProperty("prototype"),
+  'The value of !!Object.hasOwnProperty("prototype") is expected to be true'
+);
diff --git a/test/built-ins/Object/S15.2.3_A2.js b/test/built-ins/Object/S15.2.3_A2.js
index b9ec98f0c9..6c21a48f7f 100644
--- a/test/built-ins/Object/S15.2.3_A2.js
+++ b/test/built-ins/Object/S15.2.3_A2.js
@@ -8,8 +8,7 @@ info: |
 es5id: 15.2.3_A2
 description: Checking Function.prototype.isPrototypeOf(Object)
 ---*/
-
-// CHECK#
-if (!(Function.prototype.isPrototypeOf(Object))) {
-  throw new Test262Error('#1: the value of the internal [[Prototype]] property of the Object constructor is the Function prototype object.');
-}
+assert(
+  !!Function.prototype.isPrototypeOf(Object),
+  'The value of !!Function.prototype.isPrototypeOf(Object) is expected to be true'
+);
diff --git a/test/built-ins/Object/S15.2.3_A3.js b/test/built-ins/Object/S15.2.3_A3.js
index cad0df324e..7089a87156 100644
--- a/test/built-ins/Object/S15.2.3_A3.js
+++ b/test/built-ins/Object/S15.2.3_A3.js
@@ -6,13 +6,9 @@ info: Object constructor has length property whose value is 1
 es5id: 15.2.3_A3
 description: Checking Object.length
 ---*/
+assert(
+  !!Object.hasOwnProperty("length"),
+  'The value of !!Object.hasOwnProperty("length") is expected to be true'
+);
 
-//CHECK#1
-if (!Object.hasOwnProperty("length")) {
-  throw new Test262Error('#1: The Object constructor has the property "length"');
-}
-
-//CHECK#2
-if (Object.length !== 1) {
-  throw new Test262Error('#2: Object.length property value should be 1');
-}
+assert.sameValue(Object.length, 1, 'The value of Object.length is expected to be 1');
diff --git a/test/built-ins/Object/S15.2_A1.js b/test/built-ins/Object/S15.2_A1.js
index 23f9686492..8542173e2d 100644
--- a/test/built-ins/Object/S15.2_A1.js
+++ b/test/built-ins/Object/S15.2_A1.js
@@ -11,6 +11,4 @@ var obj = Object;
 
 var thisobj = this.Object;
 
-if (obj !== thisobj) {
-  throw new Test262Error('Object is the property of global');
-}
+assert.sameValue(obj, thisobj, 'The value of obj is expected to equal the value of thisobj');
diff --git a/test/built-ins/Object/S9.9_A3.js b/test/built-ins/Object/S9.9_A3.js
index 97956ab66a..af8273a0b6 100644
--- a/test/built-ins/Object/S9.9_A3.js
+++ b/test/built-ins/Object/S9.9_A3.js
@@ -8,33 +8,20 @@ info: |
 es5id: 9.9_A3
 description: Trying to convert from Boolean to Object
 ---*/
+assert.sameValue(Object(true).valueOf(), true, 'Object(true).valueOf() must return true');
+assert.sameValue(typeof Object(true), "object", 'The value of `typeof Object(true)` is expected to be "object"');
 
-// CHECK#1
-if (Object(true).valueOf() !== true) {
-  throw new Test262Error('#1: Object(true).valueOf() === true. Actual: ' + (Object(true).valueOf()));
-}
+assert.sameValue(
+  Object(true).constructor.prototype,
+  Boolean.prototype,
+  'The value of Object(true).constructor.prototype is expected to equal the value of Boolean.prototype'
+);
 
-// CHECK#2
-if (typeof Object(true) !== "object") {
-  throw new Test262Error('#2: typeof Object(true) === "object". Actual: ' + (typeof Object(true)));
-}
+assert.sameValue(Object(false).valueOf(), false, 'Object(false).valueOf() must return false');
+assert.sameValue(typeof Object(false), "object", 'The value of `typeof Object(false)` is expected to be "object"');
 
-// CHECK#3
-if (Object(true).constructor.prototype !== Boolean.prototype) {
-  throw new Test262Error('#3: Object(true).constructor.prototype === Boolean.prototype. Actual: ' + (Object(true).constructor.prototype));
-}
-
-// CHECK#4
-if (Object(false).valueOf() !== false) {
-  throw new Test262Error('#4: Object(false).valueOf() === false. Actual: ' + (Object(false).valueOf()));
-}
-
-// CHECK#5
-if (typeof Object(false) !== "object") {
-  throw new Test262Error('#5: typeof Object(false) === "object". Actual: ' + (typeof Object(false)));
-}
-
-// CHECK#6
-if (Object(false).constructor.prototype !== Boolean.prototype) {
-  throw new Test262Error('#6: Object(false).constructor.prototype === Boolean.prototype. Actual: ' + (Object(false).constructor.prototype));
-}
+assert.sameValue(
+  Object(false).constructor.prototype,
+  Boolean.prototype,
+  'The value of Object(false).constructor.prototype is expected to equal the value of Boolean.prototype'
+);
diff --git a/test/built-ins/Object/S9.9_A4.js b/test/built-ins/Object/S9.9_A4.js
index 7fc29a7aaf..904acd88dd 100644
--- a/test/built-ins/Object/S9.9_A4.js
+++ b/test/built-ins/Object/S9.9_A4.js
@@ -8,168 +8,142 @@ info: |
 es5id: 9.9_A4
 description: Converting from various numbers to Object
 ---*/
+assert.sameValue(Object(0).valueOf(), 0, 'Object(0).valueOf() must return 0');
+assert.sameValue(typeof Object(0), "object", 'The value of `typeof Object(0)` is expected to be "object"');
 
-// CHECK#1
-if (Object(0).valueOf() !== 0) {
-  throw new Test262Error('#1: Object(0).valueOf() === 0. Actual: ' + (Object(0).valueOf()));
-}
+assert.sameValue(
+  Object(0).constructor.prototype,
+  Number.prototype,
+  'The value of Object(0).constructor.prototype is expected to equal the value of Number.prototype'
+);
 
-// CHECK#2
-if (typeof Object(0) !== "object") {
-  throw new Test262Error('#2: typeof Object(0) === "object". Actual: ' + (typeof Object(0)));
-}
+assert.sameValue(Object(-0).valueOf(), -0, 'Object(-0).valueOf() must return -0');
+assert.sameValue(typeof Object(-0), "object", 'The value of `typeof Object(-0)` is expected to be "object"');
 
-// CHECK#3
-if (Object(0).constructor.prototype !== Number.prototype) {
-  throw new Test262Error('#3: Object(0).constructor.prototype === Number.prototype. Actual: ' + (Object(0).constructor.prototype));
-}
+assert.sameValue(
+  Object(-0).constructor.prototype,
+  Number.prototype,
+  'The value of Object(-0).constructor.prototype is expected to equal the value of Number.prototype'
+);
 
-// CHECK#4
-if (Object(-0).valueOf() !== -0) {
-  throw new Test262Error('#4.1: Object(-0).valueOf() === 0. Actual: ' + (Object(-0).valueOf()));
-} else if (1 / Object(-0).valueOf() !== Number.NEGATIVE_INFINITY) {
-  throw new Test262Error('#4.2: Object(-0).valueOf() === -0. Actual: +0');
-}
+assert.sameValue(Object(1).valueOf(), 1, 'Object(1).valueOf() must return 1');
+assert.sameValue(typeof Object(1), "object", 'The value of `typeof Object(1)` is expected to be "object"');
 
-// CHECK#5
-if (typeof Object(-0) !== "object") {
-  throw new Test262Error('#5: typeof Object(-0) === "object". Actual: ' + (typeof Object(-0)));
-}
+assert.sameValue(
+  Object(1).constructor.prototype,
+  Number.prototype,
+  'The value of Object(1).constructor.prototype is expected to equal the value of Number.prototype'
+);
 
-// CHECK#6
-if (Object(-0).constructor.prototype !== Number.prototype) {
-  throw new Test262Error('#6: Object(-0).constructor.prototype === Number.prototype. Actual: ' + (Object(-0).constructor.prototype));
-}
+assert.sameValue(Object(-1).valueOf(), -1, 'Object(-1).valueOf() must return -1');
+assert.sameValue(typeof Object(-1), "object", 'The value of `typeof Object(-1)` is expected to be "object"');
 
-// CHECK#7
-if (Object(1).valueOf() !== 1) {
-  throw new Test262Error('#7: Object(1).valueOf() === 1. Actual: ' + (Object(1).valueOf()));
-}
+assert.sameValue(
+  Object(-1).constructor.prototype,
+  Number.prototype,
+  'The value of Object(-1).constructor.prototype is expected to equal the value of Number.prototype'
+);
 
-// CHECK#8
-if (typeof Object(1) !== "object") {
-  throw new Test262Error('#8: typeof Object(1) === "object". Actual: ' + (typeof Object(1)));
-}
+assert.sameValue(
+  Object(Number.MIN_VALUE).valueOf(),
+  Number.MIN_VALUE,
+  'Object(Number.MIN_VALUE).valueOf() returns Number.MIN_VALUE'
+);
 
-// CHECK#9
-if (Object(1).constructor.prototype !== Number.prototype) {
-  throw new Test262Error('#9: Object(1).constructor.prototype === Number.prototype. Actual: ' + (Object(1).constructor.prototype));
-}
+assert.sameValue(
+  typeof Object(Number.MIN_VALUE),
+  "object",
+  'The value of `typeof Object(Number.MIN_VALUE)` is expected to be "object"'
+);
 
-// CHECK#10
-if (Object(-1).valueOf() !== -1) {
-  throw new Test262Error('#10: Object(-1).valueOf() === -1. Actual: ' + (Object(-1).valueOf()));
-}
+assert.sameValue(
+  Object(Number.MIN_VALUE).constructor.prototype,
+  Number.prototype,
+  'The value of Object(Number.MIN_VALUE).constructor.prototype is expected to equal the value of Number.prototype'
+);
 
-// CHECK#11
-if (typeof Object(-1) !== "object") {
-  throw new Test262Error('#11: typeof Object(-1) === "object". Actual: ' + (typeof Object(-1)));
-}
+assert.sameValue(
+  Object(Number.MAX_VALUE).valueOf(),
+  Number.MAX_VALUE,
+  'Object(Number.MAX_VALUE).valueOf() returns Number.MAX_VALUE'
+);
 
-// CHECK#12
-if (Object(-1).constructor.prototype !== Number.prototype) {
-  throw new Test262Error('#12: Object(-1).constructor.prototype === Number.prototype. Actual: ' + (Object(-1).constructor.prototype));
-}
+assert.sameValue(
+  typeof Object(Number.MAX_VALUE),
+  "object",
+  'The value of `typeof Object(Number.MAX_VALUE)` is expected to be "object"'
+);
 
-// CHECK#13
-if (Object(Number.MIN_VALUE).valueOf() !== Number.MIN_VALUE) {
-  throw new Test262Error('#13: Object(Number.MIN_VALUE).valueOf() === Number.MIN_VALUE. Actual: ' + (Object(Number.MIN_VALUE).valueOf()));
-}
+assert.sameValue(
+  Object(Number.MAX_VALUE).constructor.prototype,
+  Number.prototype,
+  'The value of Object(Number.MAX_VALUE).constructor.prototype is expected to equal the value of Number.prototype'
+);
 
-// CHECK#14
-if (typeof Object(Number.MIN_VALUE) !== "object") {
-  throw new Test262Error('#14: typeof Object(Number.MIN_VALUE) === "object". Actual: ' + (typeof Object(Number.MIN_VALUE)));
-}
+assert.sameValue(
+  Object(Number.POSITIVE_INFINITY).valueOf(),
+  Number.POSITIVE_INFINITY,
+  'Object(Number.POSITIVE_INFINITY).valueOf() returns Number.POSITIVE_INFINITY'
+);
 
-// CHECK#15
-if (Object(Number.MIN_VALUE).constructor.prototype !== Number.prototype) {
-  throw new Test262Error('#15: Object(Number.MIN_VALUE).constructor.prototype === Number.prototype. Actual: ' + (Object(Number.MIN_VALUE).constructor.prototype));
-}
+assert.sameValue(
+  typeof Object(Number.POSITIVE_INFINITY),
+  "object",
+  'The value of `typeof Object(Number.POSITIVE_INFINITY)` is expected to be "object"'
+);
 
-// CHECK#16
-if (Object(Number.MAX_VALUE).valueOf() !== Number.MAX_VALUE) {
-  throw new Test262Error('#16: Object(Number.MAX_VALUE).valueOf() === Number.MAX_VALUE. Actual: ' + (Object(Number.MAX_VALUE).valueOf()));
-}
+assert.sameValue(
+  Object(Number.POSITIVE_INFINITY).constructor.prototype,
+  Number.prototype,
+  'The value of Object(Number.POSITIVE_INFINITY).constructor.prototype is expected to equal the value of Number.prototype'
+);
 
-// CHECK#17
-if (typeof Object(Number.MAX_VALUE) !== "object") {
-  throw new Test262Error('#17: typeof Object(Number.MAX_VALUE) === "object". Actual: ' + (typeof Object(Number.MAX_VALUE)));
-}
+assert.sameValue(
+  Object(Number.NEGATIVE_INFINITY).valueOf(),
+  Number.NEGATIVE_INFINITY,
+  'Object(Number.NEGATIVE_INFINITY).valueOf() returns Number.NEGATIVE_INFINITY'
+);
 
-// CHECK#18
-if (Object(Number.MAX_VALUE).constructor.prototype !== Number.prototype) {
-  throw new Test262Error('#18: Object(Number.MAX_VALUE).constructor.prototype === Number.prototype. Actual: ' + (Object(Number.MAX_VALUE).constructor.prototype));
-}
+assert.sameValue(
+  typeof Object(Number.NEGATIVE_INFINITY),
+  "object",
+  'The value of `typeof Object(Number.NEGATIVE_INFINITY)` is expected to be "object"'
+);
 
-// CHECK#19
-if (Object(Number.POSITIVE_INFINITY).valueOf() !== Number.POSITIVE_INFINITY) {
-  throw new Test262Error('#19: Object(Number.POSITIVE_INFINITY).valueOf() === Number.POSITIVE_INFINITY. Actual: ' + (Object(Number.POSITIVE_INFINITY).valueOf()));
-}
+assert.sameValue(
+  Object(Number.NEGATIVE_INFINITY).constructor.prototype,
+  Number.prototype,
+  'The value of Object(Number.NEGATIVE_INFINITY).constructor.prototype is expected to equal the value of Number.prototype'
+);
 
-// CHECK#20
-if (typeof Object(Number.POSITIVE_INFINITY) !== "object") {
-  throw new Test262Error('#20: typeof Object(Number.POSITIVE_INFINITY) === "object". Actual: ' + (typeof Object(Number.POSITIVE_INFINITY)));
-}
+assert.sameValue(Object(NaN).valueOf(), NaN, 'Object(NaN).valueOf() returns NaN');
 
-// CHECK#21
-if (Object(Number.POSITIVE_INFINITY).constructor.prototype !== Number.prototype) {
-  throw new Test262Error('#21: Object(Number.POSITIVE_INFINITY).constructor.prototype === Number.prototype. Actual: ' + (Object(Number.POSITIVE_INFINITY).constructor.prototype));
-}
+assert.sameValue(
+  typeof Object(Number.NaN),
+  "object",
+  'The value of `typeof Object(Number.NaN)` is expected to be "object"'
+);
 
-// CHECK#22
-if (Object(Number.NEGATIVE_INFINITY).valueOf() !== Number.NEGATIVE_INFINITY) {
-  throw new Test262Error('#22: Object(Number.NEGATIVE_INFINITY).valueOf() === Number.NEGATIVE_INFINITY. Actual: ' + (Object(Number.NEGATIVE_INFINITY).valueOf()));
-}
+assert.sameValue(
+  Object(Number.NaN).constructor.prototype,
+  Number.prototype,
+  'The value of Object(Number.NaN).constructor.prototype is expected to equal the value of Number.prototype'
+);
 
-// CHECK#23
-if (typeof Object(Number.NEGATIVE_INFINITY) !== "object") {
-  throw new Test262Error('#23: typeof Object(Number.NEGATIVE_INFINITY) === "object". Actual: ' + (typeof Object(Number.NEGATIVE_INFINITY)));
-}
+assert.sameValue(Object(1.2345).valueOf(), 1.2345, 'Object(1.2345).valueOf() must return 1.2345');
+assert.sameValue(typeof Object(1.2345), "object", 'The value of `typeof Object(1.2345)` is expected to be "object"');
 
-// CHECK#24
-if (Object(Number.NEGATIVE_INFINITY).constructor.prototype !== Number.prototype) {
-  throw new Test262Error('#24: Object(Number.NEGATIVE_INFINITY).constructor.prototype === Number.prototype. Actual: ' + (Object(Number.NEGATIVE_INFINITY).constructor.prototype));
-}
+assert.sameValue(
+  Object(1.2345).constructor.prototype,
+  Number.prototype,
+  'The value of Object(1.2345).constructor.prototype is expected to equal the value of Number.prototype'
+);
 
-// CHECK#25
-assert.sameValue(Object(NaN).valueOf(), NaN, "Object(NaN).valueOf()");
+assert.sameValue(Object(-1.2345).valueOf(), -1.2345, 'Object(-1.2345).valueOf() must return -1.2345');
+assert.sameValue(typeof Object(-1.2345), "object", 'The value of `typeof Object(-1.2345)` is expected to be "object"');
 
-// CHECK#26
-if (typeof Object(Number.NaN) !== "object") {
-  throw new Test262Error('#26: typeof Object(Number.NaN) === "object". Actual: ' + (typeof Object(Number.NaN)));
-}
-
-// CHECK#27
-if (Object(Number.NaN).constructor.prototype !== Number.prototype) {
-  throw new Test262Error('#27: Object(Number.NaN).constructor.prototype === Number.prototype. Actual: ' + (Object(Number.NaN).constructor.prototype));
-}
-
-// CHECK#28
-if (Object(1.2345).valueOf() !== 1.2345) {
-  throw new Test262Error('#28: Object(1.2345).valueOf() === 1.2345. Actual: ' + (Object(1.2345).valueOf()));
-}
-
-// CHECK#29
-if (typeof Object(1.2345) !== "object") {
-  throw new Test262Error('#29: typeof Object(1.2345) === "object". Actual: ' + (typeof Object(1.2345)));
-}
-
-// CHECK#30
-if (Object(1.2345).constructor.prototype !== Number.prototype) {
-  throw new Test262Error('#30: Object(1.2345).constructor.prototype === Number.prototype. Actual: ' + (Object(1.2345).constructor.prototype));
-}
-
-// CHECK#31
-if (Object(-1.2345).valueOf() !== -1.2345) {
-  throw new Test262Error('#31: Object(-1.2345).valueOf() === -1.2345. Actual: ' + (Object(-1.2345).valueOf()));
-}
-
-// CHECK#32
-if (typeof Object(-1.2345) !== "object") {
-  throw new Test262Error('#32: typeof Object(-1.2345) === "object". Actual: ' + (typeof Object(-1.2345)));
-}
-
-// CHECK#33
-if (Object(-1.2345).constructor.prototype !== Number.prototype) {
-  throw new Test262Error('#33: Object(-1.2345).constructor.prototype === Number.prototype. Actual: ' + (Object(-1.2345).constructor.prototype));
-}
+assert.sameValue(
+  Object(-1.2345).constructor.prototype,
+  Number.prototype,
+  'The value of Object(-1.2345).constructor.prototype is expected to equal the value of Number.prototype'
+);
diff --git a/test/built-ins/Object/S9.9_A5.js b/test/built-ins/Object/S9.9_A5.js
index 32c7744775..6331c65ce1 100644
--- a/test/built-ins/Object/S9.9_A5.js
+++ b/test/built-ins/Object/S9.9_A5.js
@@ -8,63 +8,57 @@ info: |
 es5id: 9.9_A5
 description: Converting from various strings to Object
 ---*/
+assert.sameValue(
+  Object("some string").valueOf(),
+  "some string",
+  'Object("some string").valueOf() must return "some string"'
+);
 
-// CHECK#1
-if (Object("some string").valueOf() !== "some string") {
-  throw new Test262Error('#1: Object("some string").valueOf() === "some string". Actual: ' + (Object("some string").valueOf()));
-}
+assert.sameValue(
+  typeof Object("some string"),
+  "object",
+  'The value of `typeof Object("some string")` is expected to be "object"'
+);
 
-// CHECK#2
-if (typeof Object("some string") !== "object") {
-  throw new Test262Error('#2: typeof Object("some string") === "object". Actual: ' + (typeof Object("some string")));
-}
+assert.sameValue(
+  Object("some string").constructor.prototype,
+  String.prototype,
+  'The value of Object("some string").constructor.prototype is expected to equal the value of String.prototype'
+);
 
-// CHECK#3
-if (Object("some string").constructor.prototype !== String.prototype) {
-  throw new Test262Error('#3: Object("some string").constructor.prototype === String.prototype. Actual: ' + (Object("some string").constructor.prototype));
-}
+assert.sameValue(Object("").valueOf(), "", 'Object("").valueOf() must return ""');
+assert.sameValue(typeof Object(""), "object", 'The value of `typeof Object("")` is expected to be "object"');
 
-// CHECK#4
-if (Object("").valueOf() !== "") {
-  throw new Test262Error('#4: Object("").valueOf() === false. Actual: ' + (Object("").valueOf()));
-}
+assert.sameValue(
+  Object("").constructor.prototype,
+  String.prototype,
+  'The value of Object("").constructor.prototype is expected to equal the value of String.prototype'
+);
 
-// CHECK#5
-if (typeof Object("") !== "object") {
-  throw new Test262Error('#5: typeof Object("") === "object". Actual: ' + (typeof Object("")));
-}
+assert.sameValue(Object("\r\t\b\n\v\f").valueOf(), "\r\t\b\n\v\f", 'Object("rtbnvf").valueOf() must return "rtbnvf"');
 
-// CHECK#6
-if (Object("").constructor.prototype !== String.prototype) {
-  throw new Test262Error('#6: Object("").constructor.prototype === String.prototype. Actual: ' + (Object("").constructor.prototype));
-}
+assert.sameValue(
+  typeof Object("\r\t\b\n\v\f"),
+  "object",
+  'The value of `typeof Object("rtbnvf")` is expected to be "object"'
+);
 
-// CHECK#7
-if (Object("\r\t\b\n\v\f").valueOf() !== "\r\t\b\n\v\f") {
-  throw new Test262Error('#7: Object("\\r\\t\\b\\n\\v\\f").valueOf() === false. Actual: ' + (Object("\r\t\b\n\v\f").valueOf()));
-}
+assert.sameValue(
+  Object("\r\t\b\n\v\f").constructor.prototype,
+  String.prototype,
+  'The value of Object("rtbnvf").constructor.prototype is expected to equal the value of String.prototype'
+);
 
-// CHECK#8
-if (typeof Object("\r\t\b\n\v\f") !== "object") {
-  throw new Test262Error('#8: typeof Object("\\r\\t\\b\\n\\v\\f") === "object". Actual: ' + (typeof Object("\r\t\b\n\v\f")));
-}
+assert.sameValue(Object(String(10)).valueOf(), "10", 'Object(String(10)).valueOf() must return "10"');
 
-// CHECK#9
-if (Object("\r\t\b\n\v\f").constructor.prototype !== String.prototype) {
-  throw new Test262Error('#9: Object("\\r\\t\\b\\n\\v\\f").constructor.prototype === String.prototype. Actual: ' + (Object("\r\t\b\n\v\f").constructor.prototype));
-}
+assert.sameValue(
+  typeof Object(String(10)),
+  "object",
+  'The value of `typeof Object(String(10))` is expected to be "object"'
+);
 
-// CHECK#10
-if (Object(String(10)).valueOf() !== "10") {
-  throw new Test262Error('#10: Object(String(10)).valueOf() === false. Actual: ' + (Object(String(10)).valueOf()));
-}
-
-// CHECK#11
-if (typeof Object(String(10)) !== "object") {
-  throw new Test262Error('#11: typeof Object(String(10)) === "object". Actual: ' + (typeof Object(String(10))));
-}
-
-// CHECK#12
-if (Object(String(10)).constructor.prototype !== String.prototype) {
-  throw new Test262Error('#12: Object(String(10)).constructor.prototype === String.prototype. Actual: ' + (Object(String(10)).constructor.prototype));
-}
+assert.sameValue(
+  Object(String(10)).constructor.prototype,
+  String.prototype,
+  'The value of Object(String(10)).constructor.prototype is expected to equal the value of String.prototype'
+);
diff --git a/test/built-ins/Object/S9.9_A6.js b/test/built-ins/Object/S9.9_A6.js
index 15bfe5b0dd..cc222a5626 100644
--- a/test/built-ins/Object/S9.9_A6.js
+++ b/test/built-ins/Object/S9.9_A6.js
@@ -19,23 +19,13 @@ function MyObject(val) {
 var x = new MyObject(1);
 var y = Object(x);
 
-// CHECK#1
-if (y.valueOf() !== x.valueOf()) {
-  throw new Test262Error('#1: Object(obj).valueOf() === obj.valueOf(). Actual: ' + (Object(obj).valueOf()));
-}
+assert.sameValue(y.valueOf(), x.valueOf(), 'y.valueOf() must return the same value returned by x.valueOf()');
+assert.sameValue(typeof y, typeof x, 'The value of `typeof y` is expected to be typeof x');
 
-// CHECK#2
-if (typeof y !== typeof x) {
-  throw new Test262Error('#2: typeof Object(obj) === typeof obj. Actual: ' + (typeof Object(obj)));
-}
+assert.sameValue(
+  y.constructor.prototype,
+  x.constructor.prototype,
+  'The value of y.constructor.prototype is expected to equal the value of x.constructor.prototype'
+);
 
-// CHECK#3
-if (y.constructor.prototype !== x.constructor.prototype) {
-  throw new Test262Error('#3: Object(obj).constructor.prototype === obj.constructor.prototype. Actual: ' + (Object(obj).constructor.prototype));
-}
-
-
-// CHECK#4
-if (y !== x) {
-  throw new Test262Error('#4: Object(obj) === obj');
-}
+assert.sameValue(y, x, 'The value of y is expected to equal the value of x');
diff --git a/test/built-ins/Object/assign/Source-Null-Undefined.js b/test/built-ins/Object/assign/Source-Null-Undefined.js
index b41e102fc0..e81ee1179d 100644
--- a/test/built-ins/Object/assign/Source-Null-Undefined.js
+++ b/test/built-ins/Object/assign/Source-Null-Undefined.js
@@ -9,4 +9,4 @@ esid: sec-object.assign
 var target = new Object();
 var result = Object.assign(target, undefined, null);
 
-assert.sameValue(result, target, "null and undefined should be ignored, result should be original object.");
+assert.sameValue(result, target, 'The value of result is expected to equal the value of target');
diff --git a/test/built-ins/Object/assign/Source-Number-Boolen-Symbol.js b/test/built-ins/Object/assign/Source-Number-Boolen-Symbol.js
index 69ef3499a3..2949fc8723 100644
--- a/test/built-ins/Object/assign/Source-Number-Boolen-Symbol.js
+++ b/test/built-ins/Object/assign/Source-Number-Boolen-Symbol.js
@@ -12,4 +12,4 @@ features: [Symbol]
 var target = new Object();
 var result = Object.assign(target, 123, true, Symbol('foo'));
 
-assert.sameValue(result, target, "Numbers, booleans, and symbols cannot have wrappers with own enumerable properties.");
+assert.sameValue(result, target, 'The value of result is expected to equal the value of target');
diff --git a/test/built-ins/Object/assign/Source-String.js b/test/built-ins/Object/assign/Source-String.js
index 78e006461e..3b0decd047 100644
--- a/test/built-ins/Object/assign/Source-String.js
+++ b/test/built-ins/Object/assign/Source-String.js
@@ -9,6 +9,6 @@ esid: sec-object.assign
 var target = new Object();
 var result = Object.assign(target, "123");
 
-assert.sameValue(result[0], "1", "The value should be {\"0\":\"1\"}.");
-assert.sameValue(result[1], "2", "The value should be {\"1\":\"2\"}.");
-assert.sameValue(result[2], "3", "The value should be {\"2\":\"3\"}.");
+assert.sameValue(result[0], "1", 'The value of result[0] is expected to be "1"');
+assert.sameValue(result[1], "2", 'The value of result[1] is expected to be "2"');
+assert.sameValue(result[2], "3", 'The value of result[2] is expected to be "3"');
diff --git a/test/built-ins/Object/defineProperty/S15.2.3.6_A1.js b/test/built-ins/Object/defineProperty/S15.2.3.6_A1.js
index c4ee2d69c0..5f552e99c8 100644
--- a/test/built-ins/Object/defineProperty/S15.2.3.6_A1.js
+++ b/test/built-ins/Object/defineProperty/S15.2.3.6_A1.js
@@ -31,8 +31,6 @@ if (typeof document !== 'undefined' &&
   }
   if (!refused) {
     var desc = Object.getOwnPropertyDescriptor(f, 'foo');
-    if (desc.get !== getter) {
-      throw new Test262Error('Getter on HTMLFormElement disappears');
-    }
+    assert.sameValue(desc.get, getter, 'The value of desc.get is expected to equal the value of getter');
   }
 }
diff --git a/test/built-ins/Object/defineProperty/S15.2.3.6_A2.js b/test/built-ins/Object/defineProperty/S15.2.3.6_A2.js
index 2df9f1cde3..8f472abffd 100644
--- a/test/built-ins/Object/defineProperty/S15.2.3.6_A2.js
+++ b/test/built-ins/Object/defineProperty/S15.2.3.6_A2.js
@@ -17,6 +17,8 @@ function getter() {
 Object.defineProperty(base, 'foo', {
   get: getter
 });
-if (derived.hasOwnProperty('foo')) {
-  throw new Test262Error('Accessor properties inherit as own properties');
-}
+
+assert(
+  !derived.hasOwnProperty('foo'),
+  'The value of !derived.hasOwnProperty("foo") is expected to be true'
+);
diff --git a/test/built-ins/Object/getOwnPropertyNames/S15.2.3.4_A1_T1.js b/test/built-ins/Object/getOwnPropertyNames/S15.2.3.4_A1_T1.js
index 14c8bb9b11..d1675e1141 100644
--- a/test/built-ins/Object/getOwnPropertyNames/S15.2.3.4_A1_T1.js
+++ b/test/built-ins/Object/getOwnPropertyNames/S15.2.3.4_A1_T1.js
@@ -16,7 +16,5 @@ function foo() {}
 
 var names = Object.getOwnPropertyNames(foo);
 for (var i = 0, len = names.length; i < len; i++) {
-  if (!foo.hasOwnProperty(names[i])) {
-    throw new Test262Error('Phantom own property: ' + names[i]);
-  }
+  assert(!!foo.hasOwnProperty(names[i]), 'The value of !!foo.hasOwnProperty(names[i]) is expected to be true');
 }
diff --git a/test/built-ins/Object/prototype/S15.2.3.1_A1.js b/test/built-ins/Object/prototype/S15.2.3.1_A1.js
index 95bf68c92d..5af364c7ce 100644
--- a/test/built-ins/Object/prototype/S15.2.3.1_A1.js
+++ b/test/built-ins/Object/prototype/S15.2.3.1_A1.js
@@ -13,15 +13,15 @@ verifyNotWritable(Object, "prototype", null, function() {
   return "shifted";
 });
 
-//CHECK#1
-if (Object.prototype !== obj) {
-  throw new Test262Error('#1: the Object.prototype property has the attributes ReadOnly.');
-}
+assert.sameValue(Object.prototype, obj, 'The value of Object.prototype is expected to equal the value of obj');
 
-//CHECK#2
 try {
   Object.prototype();
   throw new Test262Error('#2: the Object.prototype property has the attributes ReadOnly');
 } catch (e) {
-  if (e instanceof Test262Error) throw e;
+  if (e instanceof Test262Error) {
+    throw e;
+  }
 }
+
+// TODO: Convert to verifyProperty() format.
diff --git a/test/built-ins/Object/prototype/S15.2.3.1_A2.js b/test/built-ins/Object/prototype/S15.2.3.1_A2.js
index 904495076f..d40f6ea021 100644
--- a/test/built-ins/Object/prototype/S15.2.3.1_A2.js
+++ b/test/built-ins/Object/prototype/S15.2.3.1_A2.js
@@ -6,19 +6,19 @@ info: The Object.prototype property has the attribute DontEnum
 es5id: 15.2.3.1_A2
 description: Checking if enumerating "Object.prototype" property fails
 ---*/
+assert(
+  !Object.propertyIsEnumerable('prototype'),
+  'The value of !Object.propertyIsEnumerable("prototype") is expected to be true'
+);
 
-// CHECK#1
-if (Object.propertyIsEnumerable('prototype')) {
-  throw new Test262Error('#1: the Object.prototype property has the attributes DontEnum');
-}
-
-// CHECK#2
 var cout = 0;
 
 for (var p in Object) {
-  if (p === "prototype") cout++;
+  if (p === "prototype") {
+    cout++;
+  }
 }
 
-if (cout !== 0) {
-  throw new Test262Error('#2: the Object.prototype property has the attributes DontEnum');
-}
+assert.sameValue(cout, 0, 'The value of cout is expected to be 0');
+
+// TODO: Convert to verifyProperty() format.
diff --git a/test/built-ins/Object/prototype/S15.2.3.1_A3.js b/test/built-ins/Object/prototype/S15.2.3.1_A3.js
index dc24eb5ba8..2b2dee07ac 100644
--- a/test/built-ins/Object/prototype/S15.2.3.1_A3.js
+++ b/test/built-ins/Object/prototype/S15.2.3.1_A3.js
@@ -9,17 +9,17 @@ includes: [propertyHelper.js]
 
 verifyNotConfigurable(Object, "prototype");
 
-//CHECK#1
 try {
-  if ((delete Object.prototype) !== false) {
-    throw new Test262Error('#1: Object.prototype has the attribute DontDelete');
-  }
+  assert.sameValue(delete Object.prototype, false, 'The value of `delete Object.prototype` is expected to be false');
 } catch (e) {
-  if (e instanceof Test262Error) throw e;
-  assert(e instanceof TypeError);
+  if (e instanceof Test262Error) {
+    throw e;
+  }
+  assert(e instanceof TypeError, 'The result of evaluating (e instanceof TypeError) is expected to be true');
 }
 
-//CHECK#2
 if (!(Object.hasOwnProperty('prototype'))) {
   throw new Test262Error('#2: the Object.prototype property has the attributes DontDelete.');
 }
+
+// TODO: Convert to verifyProperty() format.
diff --git a/test/built-ins/Object/prototype/S15.2.4_A1_T1.js b/test/built-ins/Object/prototype/S15.2.4_A1_T1.js
index 4e13708e22..f359fb8886 100644
--- a/test/built-ins/Object/prototype/S15.2.4_A1_T1.js
+++ b/test/built-ins/Object/prototype/S15.2.4_A1_T1.js
@@ -6,8 +6,8 @@ info: Object prototype object has not prototype
 es5id: 15.2.4_A1_T1
 description: Checking if obtaining Object.prototype.prototype fails
 ---*/
-
-// CHECK#1
-if (Object.prototype.prototype !== undefined) {
-  throw new Test262Error('#1: Object prototype has not prototype');
-}
+assert.sameValue(
+  Object.prototype.prototype,
+  undefined,
+  'The value of Object.prototype.prototype is expected to equal undefined'
+);
diff --git a/test/built-ins/Object/prototype/S15.2.4_A1_T2.js b/test/built-ins/Object/prototype/S15.2.4_A1_T2.js
index 76ee577e39..7aaea8999e 100644
--- a/test/built-ins/Object/prototype/S15.2.4_A1_T2.js
+++ b/test/built-ins/Object/prototype/S15.2.4_A1_T2.js
@@ -8,21 +8,18 @@ description: >
     Since the Object prototype object has not prototype, deleted
     toString method can not be found in prototype chain
 ---*/
-
-//CHECK#1
-if (Object.prototype.toString() == false) {
-  throw new Test262Error('#1: Object prototype object has not prototype');
-}
+assert.notSameValue(Object.prototype.toString(), false, 'Object.prototype.toString() must return false');
 
 delete Object.prototype.toString;
 
-// CHECK#2
 try {
   Object.prototype.toString();
   throw new Test262Error('#2: Object prototype object has not prototype');
 } catch (e) {
-  if ((e instanceof TypeError) !== true) {
-    throw new Test262Error('#1.1: delete Object.prototype.toString; Object.prototype.toString() throw a TypeError. Actual: ' + (e));
-  }
+  assert.sameValue(
+    e instanceof TypeError,
+    true,
+    'The result of evaluating (e instanceof TypeError) is expected to be true'
+  );
 }
 //
diff --git a/test/built-ins/Object/prototype/S15.2.4_A2.js b/test/built-ins/Object/prototype/S15.2.4_A2.js
index 9a8bc9d58e..35e9974e2d 100644
--- a/test/built-ins/Object/prototype/S15.2.4_A2.js
+++ b/test/built-ins/Object/prototype/S15.2.4_A2.js
@@ -13,7 +13,4 @@ description: >
 
 var tostr = Object.prototype.toString();
 
-//CHECK#1
-if (tostr !== "[object Object]") {
-  throw new Test262Error('#1: the value of the internal [[Class]] property of Object prototype object is "Object"');
-}
+assert.sameValue(tostr, "[object Object]", 'The value of tostr is expected to be "[object Object]"');
diff --git a/test/built-ins/Object/prototype/S15.2.4_A3.js b/test/built-ins/Object/prototype/S15.2.4_A3.js
index 855899ae67..9d298c97ca 100644
--- a/test/built-ins/Object/prototype/S15.2.4_A3.js
+++ b/test/built-ins/Object/prototype/S15.2.4_A3.js
@@ -11,4 +11,4 @@ description: Checking if calling Object prototype as a function fails
 
 assert.throws(TypeError, function() {
   Object.prototype();
-});
+}, 'Object.prototype() throws a TypeError exception');
diff --git a/test/built-ins/Object/prototype/S15.2.4_A4.js b/test/built-ins/Object/prototype/S15.2.4_A4.js
index d8459fcd72..25ed3b526e 100644
--- a/test/built-ins/Object/prototype/S15.2.4_A4.js
+++ b/test/built-ins/Object/prototype/S15.2.4_A4.js
@@ -11,4 +11,4 @@ description: Checking if creating "new Object.prototype" fails
 
 assert.throws(TypeError, function() {
   new Object.prototype;
-});
+}, '`new Object.prototype` throws a TypeError exception');
diff --git a/test/built-ins/Object/prototype/constructor/S15.2.4.1_A1_T1.js b/test/built-ins/Object/prototype/constructor/S15.2.4.1_A1_T1.js
index e73a888f0a..bafbc2f7eb 100644
--- a/test/built-ins/Object/prototype/constructor/S15.2.4.1_A1_T1.js
+++ b/test/built-ins/Object/prototype/constructor/S15.2.4.1_A1_T1.js
@@ -8,8 +8,8 @@ info: |
 es5id: 15.2.4.1_A1_T1
 description: Checking the Object.prototype.constructor
 ---*/
-
-//CHECK#1
-if (Object.prototype.constructor !== Object) {
-  throw new Test262Error('#1: The initial value of Object.prototype.constructor is the built-in Object constructor');
-}
+assert.sameValue(
+  Object.prototype.constructor,
+  Object,
+  'The value of Object.prototype.constructor is expected to equal the value of Object'
+);
diff --git a/test/built-ins/Object/prototype/constructor/S15.2.4.1_A1_T2.js b/test/built-ins/Object/prototype/constructor/S15.2.4.1_A1_T2.js
index 31183632ae..50a6303954 100644
--- a/test/built-ins/Object/prototype/constructor/S15.2.4.1_A1_T2.js
+++ b/test/built-ins/Object/prototype/constructor/S15.2.4.1_A1_T2.js
@@ -15,28 +15,14 @@ var constr = Object.prototype.constructor;
 
 var obj = new constr;
 
-// CHECK#0
-if (obj === undefined) {
-  throw new Test262Error('#0: new Object() return the newly created native object.');
-}
+assert.notSameValue(obj, undefined, 'The value of obj is expected to not equal ``undefined``');
+assert.sameValue(obj.constructor, Object, 'The value of obj.constructor is expected to equal the value of Object');
 
-// CHECK#1
-if (obj.constructor !== Object) {
-  throw new Test262Error('#1: new Object() create a new native ECMAScript object');
-}
+assert(
+  !!Object.prototype.isPrototypeOf(obj),
+  'The value of !!Object.prototype.isPrototypeOf(obj) is expected to be true'
+);
 
-// CHECK#2
-if (!(Object.prototype.isPrototypeOf(obj))) {
-  throw new Test262Error('#2: when new Object() calls the [[Prototype]] property of the newly constructed object is set to the Object prototype object.');
-}
-
-// CHECK#3
 var to_string_result = '[object ' + 'Object' + ']';
-if (obj.toString() !== to_string_result) {
-  throw new Test262Error('#3: when new Object() calls the [[Class]] property of the newly constructed object is set to "Object".');
-}
-
-// CHECK#4
-if (obj.valueOf().toString() !== to_string_result) {
-  throw new Test262Error('#4: when new Object() calls the newly constructed object has no [[Value]] property.');
-}
+assert.sameValue(obj.toString(), to_string_result, 'obj.toString() returns to_string_result');
+assert.sameValue(obj.valueOf().toString(), to_string_result, 'obj.valueOf().toString() returns to_string_result');
diff --git a/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A12.js b/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A12.js
index 6b8c1bd579..76943bd6be 100644
--- a/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A12.js
+++ b/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A12.js
@@ -10,4 +10,4 @@ description: >
 
 assert.throws(TypeError, function() {
   Object.prototype.hasOwnProperty.call(undefined, 'foo');
-});
+}, 'Object.prototype.hasOwnProperty.call(undefined, "foo") throws a TypeError exception');
diff --git a/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A13.js b/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A13.js
index e1dd5a7b02..a1aefca0b7 100644
--- a/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A13.js
+++ b/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A13.js
@@ -10,4 +10,4 @@ description: >
 
 assert.throws(TypeError, function() {
   Object.prototype.hasOwnProperty.call(null, 'foo');
-});
+}, 'Object.prototype.hasOwnProperty.call(null, "foo") throws a TypeError exception');
diff --git a/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A1_T1.js b/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A1_T1.js
index e141eb214b..67315792f0 100644
--- a/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A1_T1.js
+++ b/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A1_T1.js
@@ -13,14 +13,13 @@ description: >
     Checking type of the Object.prototype.hasOwnProperty and the
     returned result
 ---*/
+assert.sameValue(
+  typeof Object.prototype.hasOwnProperty,
+  "function",
+  'The value of `typeof Object.prototype.hasOwnProperty` is expected to be "function"'
+);
 
-//CHECK#1
-if (typeof Object.prototype.hasOwnProperty !== "function") {
-  throw new Test262Error('#1: hasOwnProperty method is defined');
-}
-
-//CHECK#2
-if (!(Object.prototype.hasOwnProperty("hasOwnProperty"))) {
-  throw new Test262Error('#2: hasOwnProperty method works properly');
-}
-//
+assert(
+  !!Object.prototype.hasOwnProperty("hasOwnProperty"),
+  'The value of !!Object.prototype.hasOwnProperty("hasOwnProperty") is expected to be true'
+);
diff --git a/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A1_T2.js b/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A1_T2.js
index d5cc9d19e9..4fe1a7638a 100644
--- a/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A1_T2.js
+++ b/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A1_T2.js
@@ -11,28 +11,28 @@ info: |
 es5id: 15.2.4.5_A1_T2
 description: Argument of the hasOwnProperty method is a custom boolean property
 ---*/
-
-//CHECK#1
-if (typeof Object.prototype.hasOwnProperty !== "function") {
-  throw new Test262Error('#1: hasOwnProperty method is defined');
-}
+assert.sameValue(
+  typeof Object.prototype.hasOwnProperty,
+  "function",
+  'The value of `typeof Object.prototype.hasOwnProperty` is expected to be "function"'
+);
 
 var obj = {
   the_property: true
 };
 
-//CHECK#2
-if (typeof obj.hasOwnProperty !== "function") {
-  throw new Test262Error('#2: hasOwnProperty method is accessed');
-}
+assert.sameValue(
+  typeof obj.hasOwnProperty,
+  "function",
+  'The value of `typeof obj.hasOwnProperty` is expected to be "function"'
+);
 
-//CHECK#3
-if (obj.hasOwnProperty("hasOwnProperty")) {
-  throw new Test262Error('#3: hasOwnProperty method works properly');
-}
+assert(
+  !obj.hasOwnProperty("hasOwnProperty"),
+  'The value of !obj.hasOwnProperty("hasOwnProperty") is expected to be true'
+);
 
-//CHECK#4
-if (!(obj.hasOwnProperty("the_property"))) {
-  throw new Test262Error('#4: hasOwnProperty method works properly');
-}
-//
+assert(
+  !!obj.hasOwnProperty("the_property"),
+  'The value of !!obj.hasOwnProperty("the_property") is expected to be true'
+);
diff --git a/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A1_T3.js b/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A1_T3.js
index 99e1f97004..997a5bfb45 100644
--- a/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A1_T3.js
+++ b/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A1_T3.js
@@ -20,22 +20,24 @@ var FACTORY = function() {
 
 var instance = new FACTORY;
 
-//CHECK#1
-if (typeof Object.prototype.hasOwnProperty !== "function") {
-  throw new Test262Error('#1: hasOwnProperty method is defined');
-}
+assert.sameValue(
+  typeof Object.prototype.hasOwnProperty,
+  "function",
+  'The value of `typeof Object.prototype.hasOwnProperty` is expected to be "function"'
+);
 
-//CHECK#2
-if (typeof instance.hasOwnProperty !== "function") {
-  throw new Test262Error('#2: hasOwnProperty method is accessed');
-}
+assert.sameValue(
+  typeof instance.hasOwnProperty,
+  "function",
+  'The value of `typeof instance.hasOwnProperty` is expected to be "function"'
+);
 
-//CHECK#3
-if (instance.hasOwnProperty("toString")) {
-  throw new Test262Error('#3: hasOwnProperty method works properly');
-}
+assert(
+  !instance.hasOwnProperty("toString"),
+  'The value of !instance.hasOwnProperty("toString") is expected to be true'
+);
 
-//CHECK#4
-if (!(instance.hasOwnProperty("aproperty"))) {
-  throw new Test262Error('#4: hasOwnProperty method works properly');
-}
+assert(
+  !!instance.hasOwnProperty("aproperty"),
+  'The value of !!instance.hasOwnProperty("aproperty") is expected to be true'
+);
diff --git a/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A6.js b/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A6.js
index be9fd54663..7b1548875f 100644
--- a/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A6.js
+++ b/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A6.js
@@ -8,9 +8,8 @@ description: >
     Checking if obtaining the prototype property of
     Object.prototype.hasOwnProperty fails
 ---*/
-
-//CHECK#1
-if (Object.prototype.hasOwnProperty.prototype !== undefined) {
-  throw new Test262Error('#1: Object.prototype.hasOwnProperty has not prototype property' + Object.prototype.hasOwnProperty.prototype);
-}
-//
+assert.sameValue(
+  Object.prototype.hasOwnProperty.prototype,
+  undefined,
+  'The value of Object.prototype.hasOwnProperty.prototype is expected to equal undefined'
+);
diff --git a/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A7.js b/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A7.js
index 8b99b376a5..bffb92c10f 100644
--- a/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A7.js
+++ b/test/built-ins/Object/prototype/hasOwnProperty/S15.2.4.5_A7.js
@@ -7,8 +7,6 @@ es5id: 15.2.4.5_A7
 description: Checking if creating "new Object.prototype.hasOwnProperty" fails
 ---*/
 
-var FACTORY = Object.prototype.hasOwnProperty;
-
 assert.throws(TypeError, function() {
-  new FACTORY;
-});
+  new Object.prototype.hasOwnProperty();
+}, '`new Object.prototype.hasOwnProperty()` throws a TypeError exception');
diff --git a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A10.js b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A10.js
index 54385a21a8..96d4e95a6a 100644
--- a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A10.js
+++ b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A10.js
@@ -11,11 +11,10 @@ description: >
     Object.prototype.propertyIsEnumerable.length property fails
 includes: [propertyHelper.js]
 ---*/
-
-//CHECK#1
-if (!(Object.prototype.propertyIsEnumerable.hasOwnProperty('length'))) {
-  throw new Test262Error('#1: the Object.prototype.propertyIsEnumerable has length property');
-}
+assert(
+  !!Object.prototype.propertyIsEnumerable.hasOwnProperty('length'),
+  'The value of !!Object.prototype.propertyIsEnumerable.hasOwnProperty("length") is expected to be true'
+);
 
 var obj = Object.prototype.propertyIsEnumerable.length;
 
@@ -23,7 +22,10 @@ verifyNotWritable(Object.prototype.propertyIsEnumerable, "length", null, functio
   return "shifted";
 });
 
-//CHECK#2
-if (Object.prototype.propertyIsEnumerable.length !== obj) {
-  throw new Test262Error('#2: the Object.prototype.propertyIsEnumerable length property has the attributes ReadOnly');
-}
+assert.sameValue(
+  Object.prototype.propertyIsEnumerable.length,
+  obj,
+  'The value of Object.prototype.propertyIsEnumerable.length is expected to equal the value of obj'
+);
+
+// TODO: Convert to verifyProperty() format.
diff --git a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A11.js b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A11.js
index 35d2d5e2da..7bf97032a4 100644
--- a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A11.js
+++ b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A11.js
@@ -6,13 +6,13 @@ info: The length property of the hasOwnProperty method is 1
 es5id: 15.2.4.7_A11
 description: Checking the value of Object.prototype.hasOwnProperty.length
 ---*/
+assert(
+  !!Object.prototype.propertyIsEnumerable.hasOwnProperty("length"),
+  'The value of !!Object.prototype.propertyIsEnumerable.hasOwnProperty("length") is expected to be true'
+);
 
-//CHECK#1
-if (!(Object.prototype.propertyIsEnumerable.hasOwnProperty("length"))) {
-  throw new Test262Error('#1: the Object.prototype.propertyIsEnumerable has length property');
-}
-
-//CHECK#2
-if (Object.prototype.propertyIsEnumerable.length !== 1) {
-  throw new Test262Error('#2: The length property of the toObject method is 1');
-}
+assert.sameValue(
+  Object.prototype.propertyIsEnumerable.length,
+  1,
+  'The value of Object.prototype.propertyIsEnumerable.length is expected to be 1'
+);
diff --git a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A12.js b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A12.js
index 880b6efa66..f95b51f33c 100644
--- a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A12.js
+++ b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A12.js
@@ -10,4 +10,4 @@ description: >
 
 assert.throws(TypeError, function() {
   Object.prototype.propertyIsEnumerable.call(undefined, 'foo');
-});
+}, 'Object.prototype.propertyIsEnumerable.call(undefined, "foo") throws a TypeError exception');
diff --git a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A13.js b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A13.js
index ec8f38591b..0db0aadd0f 100644
--- a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A13.js
+++ b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A13.js
@@ -10,4 +10,4 @@ description: >
 
 assert.throws(TypeError, function() {
   Object.prototype.propertyIsEnumerable.call(null, 'foo');
-});
+}, 'Object.prototype.propertyIsEnumerable.call(null, "foo") throws a TypeError exception');
diff --git a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A1_T1.js b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A1_T1.js
index c7e48df8f8..669dc42bbd 100644
--- a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A1_T1.js
+++ b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A1_T1.js
@@ -10,11 +10,11 @@ description: >
     Calling the propertyIsEnumerable method for object in the
     prototype chain
 ---*/
-
-//CHECK#1
-if (typeof Object.prototype.propertyIsEnumerable !== "function") {
-  throw new Test262Error('#1: propertyIsEnumerable method is defined');
-}
+assert.sameValue(
+  typeof Object.prototype.propertyIsEnumerable,
+  "function",
+  'The value of `typeof Object.prototype.propertyIsEnumerable` is expected to be "function"'
+);
 
 var proto = {
   rootprop: "avis"
@@ -22,24 +22,24 @@ var proto = {
 
 function AVISFACTORY(name) {
   this.name = name
-};
+}
 
 AVISFACTORY.prototype = proto;
 
 var seagull = new AVISFACTORY("seagull");
 
-//CHECK#2
-if (typeof seagull.propertyIsEnumerable !== "function") {
-  throw new Test262Error('#2: propertyIsEnumerable method is accessed');
-}
+assert.sameValue(
+  typeof seagull.propertyIsEnumerable,
+  "function",
+  'The value of `typeof seagull.propertyIsEnumerable` is expected to be "function"'
+);
 
-//CHECK#3
-if (!(seagull.propertyIsEnumerable("name"))) {
-  throw new Test262Error('#3: propertyIsEnumerable method works properly');
-}
+assert(
+  !!seagull.propertyIsEnumerable("name"),
+  'The value of !!seagull.propertyIsEnumerable("name") is expected to be true'
+);
 
-//CHECK#4
-if (seagull.propertyIsEnumerable("rootprop")) {
-  throw new Test262Error('#4: propertyIsEnumerable method does not consider objects in the prototype chain');
-}
-//
+assert(
+  !seagull.propertyIsEnumerable("rootprop"),
+  'The value of !seagull.propertyIsEnumerable("rootprop") is expected to be true'
+);
diff --git a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A2_T1.js b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A2_T1.js
index df53c1359f..6e29aa01e6 100644
--- a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A2_T1.js
+++ b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A2_T1.js
@@ -14,14 +14,15 @@ description: >
     Checking the type of Object.prototype.propertyIsEnumerable and the
     returned result
 ---*/
+assert.sameValue(
+  typeof Object.prototype.propertyIsEnumerable,
+  "function",
+  'The value of `typeof Object.prototype.propertyIsEnumerable` is expected to be "function"'
+);
 
-//CHECK#1
-if (typeof Object.prototype.propertyIsEnumerable !== "function") {
-  throw new Test262Error('#1: hasOwnProperty method is defined');
-}
+assert(
+  !Object.prototype.propertyIsEnumerable("propertyIsEnumerable"),
+  'The value of !Object.prototype.propertyIsEnumerable("propertyIsEnumerable") is expected to be true'
+);
 
-//CHECK#2
-if (Object.prototype.propertyIsEnumerable("propertyIsEnumerable")) {
-  throw new Test262Error('#2: hasOwnProperty method works properly');
-}
-//
+// TODO: Convert to verifyProperty() format.
diff --git a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A2_T2.js b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A2_T2.js
index c43d61ae41..2ada5b7f82 100644
--- a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A2_T2.js
+++ b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A2_T2.js
@@ -14,32 +14,31 @@ description: >
     Argument of the propertyIsEnumerable method is a custom boolean
     property
 ---*/
-
-//CHECK#1
-if (typeof Object.prototype.propertyIsEnumerable !== "function") {
-  throw new Test262Error('#1: propertyIsEnumerable method is defined');
-}
+assert.sameValue(
+  typeof Object.prototype.propertyIsEnumerable,
+  "function",
+  'The value of `typeof Object.prototype.propertyIsEnumerable` is expected to be "function"'
+);
 
 var obj = {
   the_property: true
 };
 
-//CHECK#2
-if (typeof obj.propertyIsEnumerable !== "function") {
-  throw new Test262Error('#2: propertyIsEnumerable method is accessed');
-}
+assert.sameValue(
+  typeof obj.propertyIsEnumerable,
+  "function",
+  'The value of `typeof obj.propertyIsEnumerable` is expected to be "function"'
+);
 
-//CHECK#3
-if (!(obj.propertyIsEnumerable("the_property"))) {
-  throw new Test262Error('#3: propertyIsEnumerable method works properly');
-}
+assert(
+  !!obj.propertyIsEnumerable("the_property"),
+  'The value of !!obj.propertyIsEnumerable("the_property") is expected to be true'
+);
 
-//CHECK#4
 var accum = "";
 for (var prop in obj) {
   accum += prop;
 }
-if (accum.indexOf("the_property") !== 0) {
-  throw new Test262Error('#4: enumerating works properly');
-}
-//
+assert.sameValue(accum.indexOf("the_property"), 0, 'accum.indexOf("the_property") must return 0');
+
+// TODO: Convert to verifyProperty() format.
diff --git a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A6.js b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A6.js
index 3c147edd62..25bfa31cc5 100644
--- a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A6.js
+++ b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A6.js
@@ -8,9 +8,8 @@ description: >
     Checking if obtaining the prototype property of
     Object.prototype.propertyIsEnumerable fails
 ---*/
-
-//CHECK#1
-if (Object.prototype.propertyIsEnumerable.prototype !== undefined) {
-  throw new Test262Error('#1: Object.prototype.propertyIsEnumerable has not prototype property' + Object.prototype.propertyIsEnumerable.prototype);
-}
-//
+assert.sameValue(
+  Object.prototype.propertyIsEnumerable.prototype,
+  undefined,
+  'The value of Object.prototype.propertyIsEnumerable.prototype is expected to equal undefined'
+);
diff --git a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A7.js b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A7.js
index 98ac74a123..b909f57748 100644
--- a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A7.js
+++ b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A7.js
@@ -9,8 +9,6 @@ description: >
     fails
 ---*/
 
-var FACTORY = Object.prototype.propertyIsEnumerable;
-
 assert.throws(TypeError, function() {
-  new FACTORY;
-});
+  new Object.prototype.propertyIsEnumerable();
+}, '`new Object.prototype.propertyIsEnumerable()` throws a TypeError exception');
diff --git a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A8.js b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A8.js
index b625c00039..1c85a0d87d 100644
--- a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A8.js
+++ b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A8.js
@@ -10,21 +10,19 @@ description: >
     Checking if enumerating the
     Object.prototype.propertyIsEnumerable.length property fails
 ---*/
+assert(
+  !!Object.prototype.propertyIsEnumerable.hasOwnProperty('length'),
+  'The value of !!Object.prototype.propertyIsEnumerable.hasOwnProperty("length") is expected to be true'
+);
 
-//CHECK#0
-if (!(Object.prototype.propertyIsEnumerable.hasOwnProperty('length'))) {
-  throw new Test262Error('#0: the Object.prototype.propertyIsEnumerable has length property');
-}
+assert(
+  !Object.prototype.propertyIsEnumerable.propertyIsEnumerable('length'),
+  'The value of !Object.prototype.propertyIsEnumerable.propertyIsEnumerable("length") is expected to be true'
+);
 
-
-// CHECK#1
-if (Object.prototype.propertyIsEnumerable.propertyIsEnumerable('length')) {
-  throw new Test262Error('#1: the Object.prototype.propertyIsEnumerable.length property has the attributes DontEnum');
-}
-
-// CHECK#2
 for (var p in Object.prototype.propertyIsEnumerable) {
-  if (p === "length")
-    throw new Test262Error('#2: the Object.prototype.propertyIsEnumerable.length property has the attributes DontEnum');
+  assert.notSameValue(p, "length", 'The value of p is not "length"');
 }
 //
+
+// TODO: Convert to verifyProperty() format.
diff --git a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A9.js b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A9.js
index de32336545..ba0767cd3d 100644
--- a/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A9.js
+++ b/test/built-ins/Object/prototype/propertyIsEnumerable/S15.2.4.7_A9.js
@@ -10,14 +10,14 @@ description: >
     Checking if deleting the
     Object.prototype.propertyIsEnumerable.length property fails
 ---*/
+assert(
+  !!Object.prototype.propertyIsEnumerable.hasOwnProperty('length'),
+  'The value of !!Object.prototype.propertyIsEnumerable.hasOwnProperty("length") is expected to be true'
+);
 
-//CHECK#0
-if (!(Object.prototype.propertyIsEnumerable.hasOwnProperty('length'))) {
-  throw new Test262Error('#0: the Object.prototype.propertyIsEnumerable has length property');
-}
+assert(
+  !!delete Object.prototype.propertyIsEnumerable.length,
+  'The value of !!delete Object.prototype.propertyIsEnumerable.length is expected to be true'
+);
 
-//CHECK#1
-if (!delete Object.prototype.propertyIsEnumerable.length) {
-  throw new Test262Error('#1: The Object.prototype.propertyIsEnumerable.length property does not have the attributes DontDelete');
-}
-//
+// TODO: Convert to verifyProperty() format.
diff --git a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A1.js b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A1.js
index 2cf1ea7ca2..f6de875259 100644
--- a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A1.js
+++ b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A1.js
@@ -8,18 +8,20 @@ description: >
     Checking the type of Object.prototype.toLocaleString and the
     returned result
 ---*/
+assert.sameValue(
+  typeof Object.prototype.toLocaleString,
+  "function",
+  'The value of `typeof Object.prototype.toLocaleString` is expected to be "function"'
+);
 
-//CHECK#1
-if (typeof Object.prototype.toLocaleString !== "function") {
-  throw new Test262Error('#1: toLocaleString method defined');
-}
+assert.sameValue(
+  Object.prototype.toLocaleString(),
+  Object.prototype.toString(),
+  'Object.prototype.toLocaleString() must return the same value returned by Object.prototype.toString()'
+);
 
-//CHECK#2
-if (Object.prototype.toLocaleString() !== Object.prototype.toString()) {
-  throw new Test262Error('#1: toLocaleString function returns the result of calling toString()');
-}
-
-//CHECK#2
-if ({}.toLocaleString() !== {}.toString()) {
-  throw new Test262Error('#2: toLocaleString function returns the result of calling toString()');
-}
+assert.sameValue(
+  {}.toLocaleString(),
+  {}.toString(),
+  '({}).toLocaleString() must return the same value returned by ({}).toString()'
+);
diff --git a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A10.js b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A10.js
index dfdb84f0cc..5302cb156d 100644
--- a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A10.js
+++ b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A10.js
@@ -11,11 +11,10 @@ description: >
     property fails
 includes: [propertyHelper.js]
 ---*/
-
-//CHECK#1
-if (!(Object.prototype.toLocaleString.hasOwnProperty('length'))) {
-  throw new Test262Error('#1: the Object.prototype.toLocaleString has length property.');
-}
+assert(
+  !!Object.prototype.toLocaleString.hasOwnProperty('length'),
+  'The value of !!Object.prototype.toLocaleString.hasOwnProperty("length") is expected to be true'
+);
 
 var obj = Object.prototype.toLocaleString.length;
 
@@ -23,7 +22,10 @@ verifyNotWritable(Object.prototype.toLocaleString, "length", null, function() {
   return "shifted";
 });
 
-//CHECK#2
-if (Object.prototype.toLocaleString.length !== obj) {
-  throw new Test262Error('#2: the Object.prototype.toLocaleString length property has the attributes ReadOnly.');
-}
+assert.sameValue(
+  Object.prototype.toLocaleString.length,
+  obj,
+  'The value of Object.prototype.toLocaleString.length is expected to equal the value of obj'
+);
+
+// TODO: Convert to verifyProperty() format.
diff --git a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A11.js b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A11.js
index d75b565d4e..a13bf5e5b6 100644
--- a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A11.js
+++ b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A11.js
@@ -6,13 +6,13 @@ info: The length property of the toLocaleString method is 0
 es5id: 15.2.4.3_A11
 description: Checking the Object.prototype.toLocaleString.length
 ---*/
+assert(
+  !!Object.prototype.toLocaleString.hasOwnProperty("length"),
+  'The value of !!Object.prototype.toLocaleString.hasOwnProperty("length") is expected to be true'
+);
 
-//CHECK#1
-if (!(Object.prototype.toLocaleString.hasOwnProperty("length"))) {
-  throw new Test262Error('#1: The length property of the toLocaleString method is 0');
-}
-
-//CHECK#2
-if (Object.prototype.toLocaleString.length !== 0) {
-  throw new Test262Error('#2: The length property of the toLocaleString method is 0');
-}
+assert.sameValue(
+  Object.prototype.toLocaleString.length,
+  0,
+  'The value of Object.prototype.toLocaleString.length is expected to be 0'
+);
diff --git a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A12.js b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A12.js
index a24064372e..ad5e0e27af 100644
--- a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A12.js
+++ b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A12.js
@@ -10,4 +10,4 @@ description: >
 
 assert.throws(TypeError, function() {
   Object.prototype.toLocaleString.call(undefined);
-});
+}, 'Object.prototype.toLocaleString.call(undefined) throws a TypeError exception');
diff --git a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A13.js b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A13.js
index 5a097f22e8..d2db862118 100644
--- a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A13.js
+++ b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A13.js
@@ -10,4 +10,4 @@ description: >
 
 assert.throws(TypeError, function() {
   Object.prototype.toLocaleString.call(null);
-});
+}, 'Object.prototype.toLocaleString.call(null) throws a TypeError exception');
diff --git a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A6.js b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A6.js
index 8b91c83818..434afb82b7 100644
--- a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A6.js
+++ b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A6.js
@@ -8,9 +8,8 @@ description: >
     Checking if obtaining the prototype property of
     Object.prototype.toLocaleString fails
 ---*/
-
-//CHECK#1
-if (Object.prototype.toLocaleString.prototype !== undefined) {
-  throw new Test262Error('#1: Object.prototype.toLocaleString has not prototype property' + Object.prototype.toLocaleString.prototype);
-}
-//
+assert.sameValue(
+  Object.prototype.toLocaleString.prototype,
+  undefined,
+  'The value of Object.prototype.toLocaleString.prototype is expected to equal undefined'
+);
diff --git a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A7.js b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A7.js
index b186512351..1a8a4a3e2d 100644
--- a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A7.js
+++ b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A7.js
@@ -7,8 +7,6 @@ es5id: 15.2.4.3_A7
 description: Checking if creating "new Object.prototype.toLocaleString" fails
 ---*/
 
-var FACTORY = Object.prototype.toLocaleString;
-
 assert.throws(TypeError, function() {
-  new FACTORY;
-});
+  new Object.prototype.toLocaleString();
+}, '`new Object.prototype.toLocaleString()` throws a TypeError exception');
diff --git a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A8.js b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A8.js
index 8ccaaaa0dd..346bb18271 100644
--- a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A8.js
+++ b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A8.js
@@ -10,21 +10,19 @@ description: >
     Checking if enumerating the Object.prototype.toLocaleString.length
     property fails
 ---*/
+assert(
+  !!Object.prototype.toLocaleString.hasOwnProperty('length'),
+  'The value of !!Object.prototype.toLocaleString.hasOwnProperty("length") is expected to be true'
+);
 
-//CHECK#0
-if (!(Object.prototype.toLocaleString.hasOwnProperty('length'))) {
-  throw new Test262Error('#0: the Object.prototype.toLocaleString has length property.');
-}
+assert(
+  !Object.prototype.toLocaleString.propertyIsEnumerable('length'),
+  'The value of !Object.prototype.toLocaleString.propertyIsEnumerable("length") is expected to be true'
+);
 
-
-// CHECK#1
-if (Object.prototype.toLocaleString.propertyIsEnumerable('length')) {
-  throw new Test262Error('#1: the Object.prototype.toLocaleString.length property has the attributes DontEnum');
-}
-
-// CHECK#2
 for (var p in Object.prototype.toLocaleString) {
-  if (p === "length")
-    throw new Test262Error('#2: the Object.prototype.toLocaleString.length property has the attributes DontEnum');
+  assert.notSameValue(p, "length", 'The value of p is not "length"');
 }
 //
+
+// TODO: Convert to verifyProperty() format.
diff --git a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A9.js b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A9.js
index 9ad9048933..e11791aebd 100644
--- a/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A9.js
+++ b/test/built-ins/Object/prototype/toLocaleString/S15.2.4.3_A9.js
@@ -10,18 +10,19 @@ description: >
     Checknig if deleting of the Object.prototype.toLocaleString.length
     property fails
 ---*/
+assert(
+  !!Object.prototype.toLocaleString.hasOwnProperty('length'),
+  'The value of !!Object.prototype.toLocaleString.hasOwnProperty("length") is expected to be true'
+);
 
-//CHECK#0
-if (!(Object.prototype.toLocaleString.hasOwnProperty('length'))) {
-  throw new Test262Error('#0: the Object.prototype.toLocaleString has length property');
-}
+assert(
+  !!delete Object.prototype.toLocaleString.length,
+  'The value of !!delete Object.prototype.toLocaleString.length is expected to be true'
+);
 
-//CHECK#1
-if (!delete Object.prototype.toLocaleString.length) {
-  throw new Test262Error('#1: The Object.prototype.toLocaleString.length property does not have the attributes DontDelete');
-}
+assert(
+  !Object.prototype.toLocaleString.hasOwnProperty('length'),
+  'The value of !Object.prototype.toLocaleString.hasOwnProperty("length") is expected to be true'
+);
 
-//CHECK#2
-if (Object.prototype.toLocaleString.hasOwnProperty('length')) {
-  throw new Test262Error('#2: The Object.prototype.toLocaleString.length property does not have the attributes DontDelete');
-}
+// TODO: Convert to verifyProperty() format.
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A10.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A10.js
index 87bf53f3a3..f408a7e8c8 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A10.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A10.js
@@ -9,11 +9,10 @@ description: >
     fails
 includes: [propertyHelper.js]
 ---*/
-
-//CHECK#1
-if (!(Object.prototype.valueOf.hasOwnProperty('length'))) {
-  throw new Test262Error('#1: the Object.prototype.valueOf has length property.');
-}
+assert(
+  !!Object.prototype.valueOf.hasOwnProperty('length'),
+  'The value of !!Object.prototype.valueOf.hasOwnProperty("length") is expected to be true'
+);
 
 var obj = Object.prototype.valueOf.length;
 
@@ -21,7 +20,10 @@ verifyNotWritable(Object.prototype.valueOf, "length", null, function() {
   return "shifted";
 });
 
-//CHECK#2
-if (Object.prototype.valueOf.length !== obj) {
-  throw new Test262Error('#2: the Object.prototype.valueOf length property has the attributes ReadOnly.');
-}
+assert.sameValue(
+  Object.prototype.valueOf.length,
+  obj,
+  'The value of Object.prototype.valueOf.length is expected to equal the value of obj'
+);
+
+// TODO: Convert to verifyProperty() format.
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A11.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A11.js
index a458389c8f..b114fb40bc 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A11.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A11.js
@@ -6,13 +6,13 @@ info: The length property of the valueOf method is 0
 es5id: 15.2.4.4_A11
 description: Checking the Object.prototype.valueOf.length
 ---*/
+assert(
+  !!Object.prototype.valueOf.hasOwnProperty("length"),
+  'The value of !!Object.prototype.valueOf.hasOwnProperty("length") is expected to be true'
+);
 
-//CHECK#1
-if (!(Object.prototype.valueOf.hasOwnProperty("length"))) {
-  throw new Test262Error('#1: The length property of the toObject method is 0');
-}
-
-//CHECK#2
-if (Object.prototype.valueOf.length !== 0) {
-  throw new Test262Error('#2: The length property of the toObject method is 0');
-}
+assert.sameValue(
+  Object.prototype.valueOf.length,
+  0,
+  'The value of Object.prototype.valueOf.length is expected to be 0'
+);
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A12.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A12.js
index b09d95dea9..82752e7072 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A12.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A12.js
@@ -11,4 +11,4 @@ description: Checking Object.prototype.valueOf invoked by the 'call' property.
 
 assert.throws(TypeError, function() {
   Object.prototype.valueOf.call(undefined);
-});
+}, 'Object.prototype.valueOf.call(undefined) throws a TypeError exception');
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A13.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A13.js
index 4e79dddcd6..a7f0f45c07 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A13.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A13.js
@@ -11,4 +11,4 @@ description: Checking Object.prototype.valueOf invoked by the 'call' property.
 
 assert.throws(TypeError, function() {
   Object.prototype.valueOf.call(null);
-});
+}, 'Object.prototype.valueOf.call(null) throws a TypeError exception');
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A14.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A14.js
index bff652786d..a9a6553c8c 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A14.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A14.js
@@ -11,4 +11,4 @@ description: Checking Object.prototype.valueOf invoked by the 'call' property.
 
 assert.throws(TypeError, function() {
   (1, Object.prototype.valueOf)();
-});
+}, '(1, Object.prototype.valueOf)() throws a TypeError exception');
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A15.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A15.js
index 147a31aee4..11d23d83c4 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A15.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A15.js
@@ -9,8 +9,7 @@ es5id: 15.2.4.4_A15
 description: Checking Object.prototype.valueOf when called as a global function.
 ---*/
 
-var v = Object.prototype.valueOf;
-
 assert.throws(TypeError, function() {
-  v();
-});
+  const valueOf = Object.prototype.valueOf;
+  valueOf();
+}, '`const valueOf = Object.prototype.valueOf; valueOf()` throws a TypeError exception');
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T1.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T1.js
index 8b92b63bf5..3b840882ac 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T1.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T1.js
@@ -6,20 +6,13 @@ info: The valueOf method returns its "this" value
 es5id: 15.2.4.4_A1_T1
 description: "\"this\" value is a number"
 ---*/
-
-//CHECK#1
-if (typeof Object.prototype.valueOf !== "function") {
-  throw new Test262Error('#1: valueOf method defined');
-}
+assert.sameValue(
+  typeof Object.prototype.valueOf,
+  "function",
+  'The value of `typeof Object.prototype.valueOf` is expected to be "function"'
+);
 
 var obj = new Object(1.1);
 
-//CHECK#2
-if (typeof obj.valueOf !== "function") {
-  throw new Test262Error('#2: valueOf method accessed');
-}
-
-//CHECK#3
-if (obj.valueOf() !== 1.1) {
-  throw new Test262Error('#3: The valueOf method returns its this value');
-}
+assert.sameValue(typeof obj.valueOf, "function", 'The value of `typeof obj.valueOf` is expected to be "function"');
+assert.sameValue(obj.valueOf(), 1.1, 'obj.valueOf() must return 1.1');
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T2.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T2.js
index f9957da53a..59a584892c 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T2.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T2.js
@@ -6,20 +6,13 @@ info: The valueOf method returns its "this" value
 es5id: 15.2.4.4_A1_T2
 description: "\"this\" value is a boolean"
 ---*/
-
-//CHECK#1
-if (typeof Object.prototype.valueOf !== "function") {
-  throw new Test262Error('#1: valueOf method defined');
-}
+assert.sameValue(
+  typeof Object.prototype.valueOf,
+  "function",
+  'The value of `typeof Object.prototype.valueOf` is expected to be "function"'
+);
 
 var obj = new Object(true);
 
-//CHECK#2
-if (typeof obj.valueOf !== "function") {
-  throw new Test262Error('#2: valueOf method accessed');
-}
-
-//CHECK#3
-if (obj.valueOf() !== true) {
-  throw new Test262Error('#3: The valueOf method returns its this value');
-}
+assert.sameValue(typeof obj.valueOf, "function", 'The value of `typeof obj.valueOf` is expected to be "function"');
+assert.sameValue(obj.valueOf(), true, 'obj.valueOf() must return true');
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T3.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T3.js
index 0696660a84..a3a0913970 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T3.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T3.js
@@ -6,20 +6,13 @@ info: The valueOf method returns its "this" value
 es5id: 15.2.4.4_A1_T3
 description: "\"this\" value is a string"
 ---*/
-
-//CHECK#1
-if (typeof Object.prototype.valueOf !== "function") {
-  throw new Test262Error('#1: valueOf method defined');
-}
+assert.sameValue(
+  typeof Object.prototype.valueOf,
+  "function",
+  'The value of `typeof Object.prototype.valueOf` is expected to be "function"'
+);
 
 var obj = new Object("greenfield");
 
-//CHECK#2
-if (typeof obj.valueOf !== "function") {
-  throw new Test262Error('#2: valueOf method accessed');
-}
-
-//CHECK#3
-if (obj.valueOf() !== "greenfield") {
-  throw new Test262Error('#3: The valueOf method returns its this value');
-}
+assert.sameValue(typeof obj.valueOf, "function", 'The value of `typeof obj.valueOf` is expected to be "function"');
+assert.sameValue(obj.valueOf(), "greenfield", 'obj.valueOf() must return "greenfield"');
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T4.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T4.js
index 85e4c711be..fefcecab42 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T4.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T4.js
@@ -6,20 +6,13 @@ info: The valueOf method returns its "this" value
 es5id: 15.2.4.4_A1_T4
 description: "\"this\" value is an object"
 ---*/
-
-//CHECK#1
-if (typeof Object.prototype.valueOf !== "function") {
-  throw new Test262Error('#1: valueOf method defined');
-}
+assert.sameValue(
+  typeof Object.prototype.valueOf,
+  "function",
+  'The value of `typeof Object.prototype.valueOf` is expected to be "function"'
+);
 
 var obj = new Object;
 
-//CHECK#2
-if (typeof obj.valueOf !== "function") {
-  throw new Test262Error('#2: valueOf method accessed');
-}
-
-//CHECK#3
-if (obj.valueOf() !== obj) {
-  throw new Test262Error('#3: The valueOf method returns its this value');
-}
+assert.sameValue(typeof obj.valueOf, "function", 'The value of `typeof obj.valueOf` is expected to be "function"');
+assert.sameValue(obj.valueOf(), obj, 'obj.valueOf() returns obj');
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T5.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T5.js
index b18598e28b..403bb0b7af 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T5.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T5.js
@@ -6,20 +6,13 @@ info: The valueOf method returns its "this" value
 es5id: 15.2.4.4_A1_T5
 description: "\"this\" value is \"null\""
 ---*/
-
-//CHECK#1
-if (typeof Object.prototype.valueOf !== "function") {
-  throw new Test262Error('#1: valueOf method defined');
-}
+assert.sameValue(
+  typeof Object.prototype.valueOf,
+  "function",
+  'The value of `typeof Object.prototype.valueOf` is expected to be "function"'
+);
 
 var obj = new Object(null);
 
-//CHECK#2
-if (typeof obj.valueOf !== "function") {
-  throw new Test262Error('#2: valueOf method accessed');
-}
-
-//CHECK#3
-if (obj.valueOf() !== obj) {
-  throw new Test262Error('#3: The valueOf method returns its this value');
-}
+assert.sameValue(typeof obj.valueOf, "function", 'The value of `typeof obj.valueOf` is expected to be "function"');
+assert.sameValue(obj.valueOf(), obj, 'obj.valueOf() returns obj');
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T6.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T6.js
index b37d43f01f..4436cec334 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T6.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T6.js
@@ -6,20 +6,13 @@ info: The valueOf method returns its "this" value
 es5id: 15.2.4.4_A1_T6
 description: "\"this\" value is \"undefined\""
 ---*/
-
-//CHECK#1
-if (typeof Object.prototype.valueOf !== "function") {
-  throw new Test262Error('#1: valueOf method defined');
-}
+assert.sameValue(
+  typeof Object.prototype.valueOf,
+  "function",
+  'The value of `typeof Object.prototype.valueOf` is expected to be "function"'
+);
 
 var obj = new Object(undefined);
 
-//CHECK#2
-if (typeof obj.valueOf !== "function") {
-  throw new Test262Error('#2: valueOf method accessed');
-}
-
-//CHECK#3
-if (obj.valueOf() !== obj) {
-  throw new Test262Error('#3: The valueOf method returns its this value');
-}
+assert.sameValue(typeof obj.valueOf, "function", 'The value of `typeof obj.valueOf` is expected to be "function"');
+assert.sameValue(obj.valueOf(), obj, 'obj.valueOf() returns obj');
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T7.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T7.js
index 6c8a26d36e..5e224d37bd 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T7.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A1_T7.js
@@ -6,20 +6,13 @@ info: The valueOf method returns its "this" value
 es5id: 15.2.4.4_A1_T7
 description: "\"this\" value is \"void 0\""
 ---*/
-
-//CHECK#1
-if (typeof Object.prototype.valueOf !== "function") {
-  throw new Test262Error('#1: valueOf method defined');
-}
+assert.sameValue(
+  typeof Object.prototype.valueOf,
+  "function",
+  'The value of `typeof Object.prototype.valueOf` is expected to be "function"'
+);
 
 var obj = new Object(void 0);
 
-//CHECK#2
-if (typeof obj.valueOf !== "function") {
-  throw new Test262Error('#2: valueOf method accessed');
-}
-
-//CHECK#3
-if (obj.valueOf() !== obj) {
-  throw new Test262Error('#3: The valueOf method returns its this value');
-}
+assert.sameValue(typeof obj.valueOf, "function", 'The value of `typeof obj.valueOf` is expected to be "function"');
+assert.sameValue(obj.valueOf(), obj, 'obj.valueOf() returns obj');
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A6.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A6.js
index bf374ff792..1b37ab34ce 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A6.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A6.js
@@ -8,9 +8,8 @@ description: >
     Checking if obtaining the prototype property of
     Object.prototype.valueOf fails
 ---*/
-
-//CHECK#1
-if (Object.prototype.valueOf.prototype !== undefined) {
-  throw new Test262Error('#1: Object.prototype.valueOf has not prototype property' + Object.prototype.valueOf.prototype);
-}
-//
+assert.sameValue(
+  Object.prototype.valueOf.prototype,
+  undefined,
+  'The value of Object.prototype.valueOf.prototype is expected to equal undefined'
+);
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A7.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A7.js
index 2a6eb9c405..f8744b6aef 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A7.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A7.js
@@ -7,8 +7,6 @@ es5id: 15.2.4.4_A7
 description: Checking if creating "new Object.prototype.valueOf" fails
 ---*/
 
-var FACTORY = Object.prototype.valueOf;
-
 assert.throws(TypeError, function() {
-  new FACTORY;
-});
+  new Object.prototype.valueOf();
+}, '`new Object.prototype.valueOf()` throws a TypeError exception');
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A8.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A8.js
index 85d4bd9b79..fe662ccc08 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A8.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A8.js
@@ -8,21 +8,19 @@ description: >
     Checking if enumerating the Object.prototype.valueOf.length
     property fails
 ---*/
+assert(
+  !!Object.prototype.valueOf.hasOwnProperty('length'),
+  'The value of !!Object.prototype.valueOf.hasOwnProperty("length") is expected to be true'
+);
 
-//CHECK#0
-if (!(Object.prototype.valueOf.hasOwnProperty('length'))) {
-  throw new Test262Error('#0: the Object.prototype.valueOf has length property.');
-}
+assert(
+  !Object.prototype.valueOf.propertyIsEnumerable('length'),
+  'The value of !Object.prototype.valueOf.propertyIsEnumerable("length") is expected to be true'
+);
 
-
-// CHECK#1
-if (Object.prototype.valueOf.propertyIsEnumerable('length')) {
-  throw new Test262Error('#1: the Object.prototype.valueOf.length property has the attributes DontEnum');
-}
-
-// CHECK#2
 for (var p in Object.prototype.valueOf) {
-  if (p === "length")
-    throw new Test262Error('#2: the Object.prototype.valueOf.length property has the attributes DontEnum');
+  assert.notSameValue(p, "length", 'The value of p is not "length"');
 }
 //
+
+// TODO: Convert to verifyProperty() format.
diff --git a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A9.js b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A9.js
index a5d2960c29..b182332c66 100644
--- a/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A9.js
+++ b/test/built-ins/Object/prototype/valueOf/S15.2.4.4_A9.js
@@ -10,18 +10,19 @@ description: >
     Checknig if deleting of the Object.prototype.valueOf.length
     property fails
 ---*/
+assert(
+  !!Object.prototype.valueOf.hasOwnProperty('length'),
+  'The value of !!Object.prototype.valueOf.hasOwnProperty("length") is expected to be true'
+);
 
-//CHECK#0
-if (!(Object.prototype.valueOf.hasOwnProperty('length'))) {
-  throw new Test262Error('#0: the Object.prototype.valueOf has length property');
-}
+assert(
+  !!delete Object.prototype.valueOf.length,
+  'The value of !!delete Object.prototype.valueOf.length is expected to be true'
+);
 
-//CHECK#1
-if (!delete Object.prototype.valueOf.length) {
-  throw new Test262Error('#1: The Object.prototype.valueOf.length property does not have the attributes DontDelete');
-}
+assert(
+  !Object.prototype.valueOf.hasOwnProperty('length'),
+  'The value of !Object.prototype.valueOf.hasOwnProperty("length") is expected to be true'
+);
 
-//CHECK#2
-if (Object.prototype.valueOf.hasOwnProperty('length')) {
-  throw new Test262Error('#2: The Object.prototype.valueOf.length property does not have the attributes DontDelete');
-}
+// TODO: Convert to verifyProperty() format.