diff --git a/test/built-ins/Symbol/prototype/description/description-symboldescriptivestring.js b/test/built-ins/Symbol/prototype/description/description-symboldescriptivestring.js
new file mode 100644
index 0000000000..0bf5e63993
--- /dev/null
+++ b/test/built-ins/Symbol/prototype/description/description-symboldescriptivestring.js
@@ -0,0 +1,32 @@
+// Copyright (C) 2018 Rick Waldron. All rights reserved.
+// Copyright (C) 2018 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-symbol.prototype.description
+description: >
+  SymbolDescriptiveString(sym) via Symbol.prototype.toString()
+info: |
+  SymbolDescriptiveString ( sym )
+
+  Assert: Type(sym) is Symbol.
+  Let desc be sym's [[Description]] value.
+  If desc is undefined, let desc be the empty string.
+  Assert: Type(desc) is String.
+  Return the string-concatenation of "Symbol(", desc, and ")".
+
+includes: [propertyHelper.js]
+features: [Symbol.prototype.description]
+---*/
+
+const symbol = Symbol('foo');
+
+assert.sameValue(
+  symbol.description,
+  'foo',
+  'The value of symbol.description is "foo"'
+);
+assert.sameValue(
+  symbol.toString(),
+  `Symbol(${symbol.description})`,
+  `symbol.toString() returns "Symbol(${symbol.description})"`
+);
diff --git a/test/built-ins/Symbol/prototype/description/descriptor.js b/test/built-ins/Symbol/prototype/description/descriptor.js
index bc66519624..25c4f14d54 100644
--- a/test/built-ins/Symbol/prototype/description/descriptor.js
+++ b/test/built-ins/Symbol/prototype/description/descriptor.js
@@ -15,9 +15,23 @@ features: [Symbol.prototype.description]
 
 var desc = Object.getOwnPropertyDescriptor(Symbol.prototype, 'description');
 
-assert.sameValue(desc.set, undefined);
-assert.sameValue(desc.writable, undefined);
-assert.sameValue(typeof desc.get, 'function');
+assert.sameValue(
+  desc.set,
+  undefined,
+  'The value of desc.set is `undefined`'
+);
+
+assert.sameValue(
+  desc.writable,
+  undefined,
+  'The value of desc.writable is `undefined`'
+);
+
+assert.sameValue(
+  typeof desc.get,
+  'function',
+  'The value of `typeof desc.get` is "function"'
+);
 
 verifyProperty(Symbol.prototype, 'description', {
   enumerable: false,
diff --git a/test/built-ins/Symbol/prototype/description/get.js b/test/built-ins/Symbol/prototype/description/get.js
index 54c0fb06b2..e6530cba8f 100644
--- a/test/built-ins/Symbol/prototype/description/get.js
+++ b/test/built-ins/Symbol/prototype/description/get.js
@@ -13,17 +13,29 @@ features: [Symbol.prototype.description]
 ---*/
 
 const symbol = Symbol('test');
-assert.sameValue(symbol.description, 'test');
-assert.sameValue(symbol.hasOwnProperty('description'), false);
+assert.sameValue(
+  symbol.description,
+  'test',
+  'The value of symbol.description is "test"'
+);
 
 const empty = Symbol();
-assert.sameValue(empty.description, undefined);
-assert.sameValue(empty.hasOwnProperty('description'), false);
+assert.sameValue(
+  empty.description,
+  undefined,
+  'The value of empty.description is `undefined`'
+);
 
 const undef = Symbol(undefined);
-assert.sameValue(undef.description, undefined);
-assert.sameValue(undef.hasOwnProperty('description'), false);
+assert.sameValue(
+  undef.description,
+  undefined,
+  'The value of undef.description is `undefined`'
+);
 
 const emptyStr = Symbol('');
-assert.sameValue(emptyStr.description, '');
-assert.sameValue(emptyStr.hasOwnProperty('description'), false);
+assert.sameValue(
+  emptyStr.description,
+  '',
+  'The value of emptyStr.description is ""'
+);
diff --git a/test/built-ins/Symbol/prototype/description/is-not-own-property.js b/test/built-ins/Symbol/prototype/description/is-not-own-property.js
new file mode 100644
index 0000000000..88ad30fd5e
--- /dev/null
+++ b/test/built-ins/Symbol/prototype/description/is-not-own-property.js
@@ -0,0 +1,14 @@
+// Copyright 2018 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-symbol.prototype.description
+description: Ensure that 'description' is not an own property of Symbols
+features: [Symbol.prototype.description]
+---*/
+
+assert.sameValue(
+  Symbol().hasOwnProperty('description'),
+  false,
+  'Symbol().hasOwnProperty("description") returns false'
+);
diff --git a/test/built-ins/Symbol/prototype/description/this-val-non-symbol.js b/test/built-ins/Symbol/prototype/description/this-val-non-symbol.js
index 0d2fc40b18..b85c48cbf4 100644
--- a/test/built-ins/Symbol/prototype/description/this-val-non-symbol.js
+++ b/test/built-ins/Symbol/prototype/description/this-val-non-symbol.js
@@ -4,7 +4,7 @@
 /*---
 esid: sec-symbol.prototype.description
 description: >
-    Behavior when `this` value is an object without a [[SymbolData]] internal
+    Behavior when "this" value is an object without a [[SymbolData]] internal
     slot.
 info: |
     1. Let s be the this value.
@@ -19,28 +19,28 @@ const getter = Object.getOwnPropertyDescriptor(
 
 assert.throws(TypeError, function() {
   getter.call(null);
-});
+}, 'getter.call(null) throws TypeError');
 
 assert.throws(TypeError, function() {
   getter.call(123);
-});
+}, 'getter.call(123) throws TypeError');
 
 assert.throws(TypeError, function() {
   getter.call('test');
-});
+}, 'getter.call("test") throws TypeError');
 
 assert.throws(TypeError, function() {
   getter.call(true);
-});
+}, 'getter.call(true) throws TypeError');
 
 assert.throws(TypeError, function() {
   getter.call(undefined);
-});
+}, 'getter.call(undefined) throws TypeError');
 
 assert.throws(TypeError, function() {
   getter.call(new Proxy({}, {}));
-});
+}, 'getter.call(new Proxy({}, {})) throws TypeError');
 
 assert.throws(TypeError, function() {
   getter.call({});
-});
+}, 'getter.call({}) throws TypeError');
diff --git a/test/built-ins/Symbol/prototype/description/this-val-symbol.js b/test/built-ins/Symbol/prototype/description/this-val-symbol.js
index 604e4e47ea..d49359a8a3 100644
--- a/test/built-ins/Symbol/prototype/description/this-val-symbol.js
+++ b/test/built-ins/Symbol/prototype/description/this-val-symbol.js
@@ -17,17 +17,49 @@ const getter = Object.getOwnPropertyDescriptor(
 ).get;
 
 const symbol = Symbol('test');
-assert.sameValue(getter.call(symbol), 'test');
-assert.sameValue(getter.call(Object(symbol)), 'test');
+assert.sameValue(
+  getter.call(symbol),
+  'test',
+  'getter.call(symbol) returns "test"'
+);
+assert.sameValue(
+  getter.call(Object(symbol)),
+  'test',
+  'getter.call(Object(symbol)) returns "test"'
+);
 
 const empty = Symbol();
-assert.sameValue(getter.call(empty), undefined);
-assert.sameValue(getter.call(Object(empty)), undefined);
+assert.sameValue(
+  getter.call(empty),
+  undefined,
+  'getter.call(empty) returns `undefined`'
+);
+assert.sameValue(
+  getter.call(Object(empty)),
+  undefined,
+  'getter.call(Object(empty)) returns `undefined`'
+);
 
 const undef = Symbol(undefined);
-assert.sameValue(getter.call(undef), undefined);
-assert.sameValue(getter.call(Object(undef)), undefined);
+assert.sameValue(
+  getter.call(undef),
+  undefined,
+  'getter.call(undef) returns `undefined`'
+);
+assert.sameValue(
+  getter.call(Object(undef)),
+  undefined,
+  'getter.call(Object(undef)) returns `undefined`'
+);
 
 const emptyStr = Symbol('');
-assert.sameValue(getter.call(emptyStr), '');
-assert.sameValue(getter.call(Object(emptyStr)), '');
+assert.sameValue(
+  getter.call(emptyStr),
+  '',
+  'getter.call(emptyStr) returns ""'
+);
+assert.sameValue(
+  getter.call(Object(emptyStr)),
+  '',
+  'getter.call(Object(emptyStr)) returns ""'
+);
diff --git a/test/built-ins/Symbol/prototype/description/wrapper.js b/test/built-ins/Symbol/prototype/description/wrapper.js
index c117f1b73c..8aac889d7b 100644
--- a/test/built-ins/Symbol/prototype/description/wrapper.js
+++ b/test/built-ins/Symbol/prototype/description/wrapper.js
@@ -13,17 +13,29 @@ features: [Symbol.prototype.description]
 ---*/
 
 const symbol = Object(Symbol('test'));
-assert.sameValue(symbol.description, 'test');
-assert.sameValue(symbol.hasOwnProperty('description'), false);
+assert.sameValue(
+  symbol.description,
+  'test',
+  'The value of symbol.description is "test"'
+);
 
 const empty = Object(Symbol());
-assert.sameValue(empty.description, undefined);
-assert.sameValue(empty.hasOwnProperty('description'), false);
+assert.sameValue(
+  empty.description,
+  undefined,
+  'The value of empty.description is `undefined`'
+);
 
 const undef = Object(Symbol(undefined));
-assert.sameValue(undef.description, undefined);
-assert.sameValue(undef.hasOwnProperty('description'), false);
+assert.sameValue(
+  undef.description,
+  undefined,
+  'The value of undef.description is `undefined`'
+);
 
 const emptyStr = Object(Symbol(''));
-assert.sameValue(emptyStr.description, '');
-assert.sameValue(emptyStr.hasOwnProperty('description'), false);
+assert.sameValue(
+  emptyStr.description,
+  '',
+  'The value of emptyStr.description is ""'
+);