diff --git a/test/built-ins/Array/prototype/flat/array-like-objects.js b/test/built-ins/Array/prototype/flat/array-like-objects.js
index 4cd131b85b..9c9303ff1a 100644
--- a/test/built-ins/Array/prototype/flat/array-like-objects.js
+++ b/test/built-ins/Array/prototype/flat/array-like-objects.js
@@ -16,16 +16,16 @@ var a = getArgumentsObject([1], [2]);
 var actual = [].flat.call(a);
 assert.compareArray(actual, [1, 2], 'arguments objects');
 
-var a = {
+a = {
   length: 1,
   0: [1],
 };
-var actual = [].flat.call(a);
+actual = [].flat.call(a);
 assert.compareArray(actual, [1], 'array-like objects');
 
-var a = {
+a = {
   length: undefined,
   0: [1],
 };
-var actual = [].flat.call(a);
+actual = [].flat.call(a);
 assert.compareArray(actual, [], 'array-like objects; undefined length');
diff --git a/test/built-ins/Array/prototype/flat/length.js b/test/built-ins/Array/prototype/flat/length.js
index 4c0896f349..e92beff304 100644
--- a/test/built-ins/Array/prototype/flat/length.js
+++ b/test/built-ins/Array/prototype/flat/length.js
@@ -14,6 +14,8 @@ assert.sameValue(
   'The value of `Array.prototype.flat.length` is `0`'
 );
 
-verifyNotEnumerable(Array.prototype.flat, 'length');
-verifyNotWritable(Array.prototype.flat, 'length');
-verifyConfigurable(Array.prototype.flat, 'length');
+verifyProperty(Array.prototype.flat, 'length', {
+  enumerable: false,
+  writable: false,
+  configurable: true,
+});
diff --git a/test/built-ins/Array/prototype/flat/name.js b/test/built-ins/Array/prototype/flat/name.js
index 312827bc1a..18debef96f 100644
--- a/test/built-ins/Array/prototype/flat/name.js
+++ b/test/built-ins/Array/prototype/flat/name.js
@@ -15,6 +15,8 @@ assert.sameValue(
   'The value of `Array.prototype.flat.name` is `"flat"`'
 );
 
-verifyNotEnumerable(Array.prototype.flat, 'name');
-verifyNotWritable(Array.prototype.flat, 'name');
-verifyConfigurable(Array.prototype.flat, 'name');
+verifyProperty(Array.prototype.flat, 'name', {
+  enumerable: false,
+  writable: false,
+  configurable: true,
+});
diff --git a/test/built-ins/Array/prototype/flat/non-numeric-depth-should-not-throw.js b/test/built-ins/Array/prototype/flat/non-numeric-depth-should-not-throw.js
index 68f229a243..946465094c 100644
--- a/test/built-ins/Array/prototype/flat/non-numeric-depth-should-not-throw.js
+++ b/test/built-ins/Array/prototype/flat/non-numeric-depth-should-not-throw.js
@@ -17,27 +17,27 @@ var actual = a.flat(depthNum);
 assert(compareArray(actual, expected), 'non integral string depthNum');
 
 // object type depthNum is converted to 0
-var depthNum = {};
-var actual = a.flat(depthNum);
+depthNum = {};
+actual = a.flat(depthNum);
 assert(compareArray(actual, expected), 'object type depthNum');
 
 // negative infinity depthNum is converted to 0
-var depthNum = Number.NEGATIVE_INFINITY;
-var actual = a.flat(depthNum);
+depthNum = Number.NEGATIVE_INFINITY;
+actual = a.flat(depthNum);
 assert(compareArray(actual, expected), 'negative infinity depthNum');
 
 // positive zero depthNum is converted to 0
-var depthNum = +0;
-var actual = a.flat(depthNum);
+depthNum = +0;
+actual = a.flat(depthNum);
 assert(compareArray(actual, expected), 'positive zero depthNum');
 
 // negative zero depthNum is converted to 0
-var depthNum = -0;
-var actual = a.flat(depthNum);
+depthNum = -0;
+actual = a.flat(depthNum);
 assert(compareArray(actual, expected), 'negative zero depthNum');
 
 // integral string depthNum is converted to an integer
-var depthNum = '1';
-var actual = a.flat(depthNum);
-var expected = [1, 2]
+depthNum = '1';
+actual = a.flat(depthNum);
+expected = [1, 2]
 assert(compareArray(actual, expected), 'integral string depthNum');
diff --git a/test/built-ins/Array/prototype/flat/non-object-ctor-throws.js b/test/built-ins/Array/prototype/flat/non-object-ctor-throws.js
index eb4f5ca092..1d3e595cd3 100644
--- a/test/built-ins/Array/prototype/flat/non-object-ctor-throws.js
+++ b/test/built-ins/Array/prototype/flat/non-object-ctor-throws.js
@@ -14,19 +14,19 @@ assert.throws(TypeError, function() {
   a.flat();
 }, 'null value');
 
-var a = [];
+a = [];
 a.constructor = 1;
 assert.throws(TypeError, function() {
   a.flat();
 }, 'number value');
 
-var a = [];
+a = [];
 a.constructor = 'string';
 assert.throws(TypeError, function() {
   a.flat();
 }, 'string value');
 
-var a = [];
+a = [];
 a.constructor = true;
 assert.throws(TypeError, function() {
   a.flat();
diff --git a/test/built-ins/Array/prototype/flat/prop-desc.js b/test/built-ins/Array/prototype/flat/prop-desc.js
index c538b2b7b7..4ee68c38d8 100644
--- a/test/built-ins/Array/prototype/flat/prop-desc.js
+++ b/test/built-ins/Array/prototype/flat/prop-desc.js
@@ -2,7 +2,6 @@
 // This code is governed by the BSD license found in the LICENSE file.
 /*---
 esid: sec-array.prototype.flat
-es6id: 22.1.3
 description: Property type and descriptor.
 info: >
   17 ECMAScript Standard Built-in Objects
@@ -16,6 +15,8 @@ assert.sameValue(
   '`typeof Array.prototype.flat` is `function`'
 );
 
-verifyNotEnumerable(Array.prototype, 'flat');
-verifyWritable(Array.prototype, 'flat');
-verifyConfigurable(Array.prototype, 'flat');
+verifyProperty(Array.prototype, 'flat', {
+  enumerable: false,
+  writable: true,
+  configurable: true,
+});
diff --git a/test/built-ins/Array/prototype/flat/proxy-access-count.js b/test/built-ins/Array/prototype/flat/proxy-access-count.js
index 0c691e079a..9dbc4839c2 100644
--- a/test/built-ins/Array/prototype/flat/proxy-access-count.js
+++ b/test/built-ins/Array/prototype/flat/proxy-access-count.js
@@ -3,12 +3,24 @@
 /*---
 esid: sec-array.prototype.flat
 description: >
-    properties are accessed correct number of times by .flat
+  properties are accessed correct number of times by .flat
+info: |
+  Array.prototype.flat( [ depth ] )
+
+  ...
+  6. Perform ? FlattenIntoArray(A, O, sourceLen, 0, depthNum).
+
+  FlattenIntoArray (target, source, sourceLen, start, depth [ , mapperFunction, thisArg ])
+
+  3. Repeat, while sourceIndex < sourceLen
+    a. Let P be ! ToString(sourceIndex).
+    b. Let exists be ? HasProperty(source, P).
+    c. If exists is true, then
+      i. Let element be ? Get(source, P).
 features: [Array.prototype.flat]
 includes: [compareArray.js]
 ---*/
 
-
 const getCalls = [], hasCalls = [];
 const handler = {
   get : function (t, p, r) { getCalls.push(p); return Reflect.get(t, p, r); },
diff --git a/test/built-ins/Array/prototype/flatMap/array-like-objects.js b/test/built-ins/Array/prototype/flatMap/array-like-objects.js
index a9512ff35f..8b2c597a84 100644
--- a/test/built-ins/Array/prototype/flatMap/array-like-objects.js
+++ b/test/built-ins/Array/prototype/flatMap/array-like-objects.js
@@ -20,16 +20,16 @@ var a = getArgumentsObject(1, 2);
 var actual = [].flatMap.call(a, double);
 assert.compareArray(actual, [2, 4], 'arguments objects');
 
-var a = {
+a = {
   length: 1,
   0: 1,
 };
-var actual = [].flatMap.call(a, double);
+actual = [].flatMap.call(a, double);
 assert.compareArray(actual, [2], 'array-like objects');
 
-var a = {
+a = {
   length: void 0,
   0: 1,
 };
-var actual = [].flatMap.call(a, double);
+actual = [].flatMap.call(a, double);
 assert.compareArray(actual, [], 'array-like objects; undefined length');
diff --git a/test/built-ins/Array/prototype/flatMap/length.js b/test/built-ins/Array/prototype/flatMap/length.js
index c5fc1b3a36..67152cddb3 100644
--- a/test/built-ins/Array/prototype/flatMap/length.js
+++ b/test/built-ins/Array/prototype/flatMap/length.js
@@ -14,6 +14,8 @@ assert.sameValue(
   'The value of `Array.prototype.flatmap.length` is `1`'
 );
 
-verifyNotEnumerable(Array.prototype.flatMap, 'length');
-verifyNotWritable(Array.prototype.flatMap, 'length');
-verifyConfigurable(Array.prototype.flatMap, 'length');
+verifyProperty(Array.prototype.flatMap, 'length', {
+  enumerable: false,
+  writable: false,
+  configurable: true,
+});
diff --git a/test/built-ins/Array/prototype/flatMap/name.js b/test/built-ins/Array/prototype/flatMap/name.js
index 98ea548a4b..3b5ec271c1 100644
--- a/test/built-ins/Array/prototype/flatMap/name.js
+++ b/test/built-ins/Array/prototype/flatMap/name.js
@@ -14,6 +14,8 @@ assert.sameValue(
   'The value of `Array.prototype.flatMap.name` is `"flatMap"`'
 );
 
-verifyNotEnumerable(Array.prototype.flatMap, 'name');
-verifyNotWritable(Array.prototype.flatMap, 'name');
-verifyConfigurable(Array.prototype.flatMap, 'name');
+verifyProperty(Array.prototype.flatMap, 'name', {
+  enumerable: false,
+  writable: false,
+  configurable: true,
+});
diff --git a/test/built-ins/Array/prototype/flatMap/non-object-ctor-throws.js b/test/built-ins/Array/prototype/flatMap/non-object-ctor-throws.js
index 65767d2ce4..b54e27746a 100644
--- a/test/built-ins/Array/prototype/flatMap/non-object-ctor-throws.js
+++ b/test/built-ins/Array/prototype/flatMap/non-object-ctor-throws.js
@@ -14,19 +14,19 @@ assert.throws(TypeError, function() {
   a.flatMap();
 }, 'null value');
 
-var a = [];
+a = [];
 a.constructor = 1;
 assert.throws(TypeError, function() {
   a.flatMap();
 }, 'number value');
 
-var a = [];
+a = [];
 a.constructor = 'string';
 assert.throws(TypeError, function() {
   a.flatMap();
 }, 'string value');
 
-var a = [];
+a = [];
 a.constructor = true;
 assert.throws(TypeError, function() {
   a.flatMap();
diff --git a/test/built-ins/Array/prototype/flatMap/prop-desc.js b/test/built-ins/Array/prototype/flatMap/prop-desc.js
new file mode 100644
index 0000000000..1ea4930e69
--- /dev/null
+++ b/test/built-ins/Array/prototype/flatMap/prop-desc.js
@@ -0,0 +1,27 @@
+// Copyright (C) 2018 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.flatMap
+description: Property type and descriptor.
+info: >
+  17 ECMAScript Standard Built-in Objects
+
+  Every other data property described in clauses 18 through 26 and in Annex B.2
+  has the attributes { [[Writable]]: true, [[Enumerable]]: false,
+  [[Configurable]]: true } unless otherwise specified.
+includes: [propertyHelper.js]
+features: [Array.prototype.flatMap]
+---*/
+
+assert.sameValue(
+  typeof Array.prototype.flatMap,
+  'function',
+  '`typeof Array.prototype.flatMap` is `function`'
+);
+
+verifyProperty(Array.prototype, 'flatMap', {
+  enumerable: false,
+  writable: true,
+  configurable: true,
+});
diff --git a/test/built-ins/Array/prototype/flatMap/proxy-access-count.js b/test/built-ins/Array/prototype/flatMap/proxy-access-count.js
index 8cb851e024..8b33348c69 100644
--- a/test/built-ins/Array/prototype/flatMap/proxy-access-count.js
+++ b/test/built-ins/Array/prototype/flatMap/proxy-access-count.js
@@ -3,12 +3,24 @@
 /*---
 esid: sec-array.prototype.flatMap
 description: >
-    properties are accessed correct number of times by .flatMap
+  properties are accessed correct number of times by .flatMap
+info: |
+  Array.prototype.flatMap ( mapperFunction [ , thisArg ] )
+
+  ...
+  6. Perform ? FlattenIntoArray(A, O, sourceLen, 0, 1, mapperFunction, T).
+
+  FlattenIntoArray (target, source, sourceLen, start, depth [ , mapperFunction, thisArg ])
+
+  3. Repeat, while sourceIndex < sourceLen
+    a. Let P be ! ToString(sourceIndex).
+    b. Let exists be ? HasProperty(source, P).
+    c. If exists is true, then
+      i. Let element be ? Get(source, P).
 features: [Array.prototype.flat]
 includes: [compareArray.js]
 ---*/
 
-
 const getCalls = [], hasCalls = [];
 const handler = {
   get : function (t, p, r) { getCalls.push(p); return Reflect.get(t, p, r); },