diff --git a/test/built-ins/Object/assign/OnlyOneArgument.js b/test/built-ins/Object/assign/OnlyOneArgument.js
index 9131e1146afd26092ca6b1a2e7fc742877df12cb..1c5f90faec062f20ffe25f103fa30015fef52971 100644
--- a/test/built-ins/Object/assign/OnlyOneArgument.js
+++ b/test/built-ins/Object/assign/OnlyOneArgument.js
@@ -10,4 +10,5 @@ es6id: 19.1.2.1.3
var target = "a";
var result = Object.assign(target);
+assert.sameValue(typeof result, "object");
assert.sameValue(result.valueOf(), "a", "The value should be 'a'.");
diff --git a/test/built-ins/Object/assign/assign-length.js b/test/built-ins/Object/assign/assign-length.js
index b49b0a7149416adb92a6b1ee76d77a93f11a9bbd..2509132255f38111d219ceb12160161d138d08d0 100644
--- a/test/built-ins/Object/assign/assign-length.js
+++ b/test/built-ins/Object/assign/assign-length.js
@@ -4,6 +4,21 @@
/*---
description: The length property of the assign method should be 2
es6id: 19.1.2.1
+info: >
+ The length property of the assign method is 2.
+
+ ES6 Section 17:
+
+ Unless otherwise specified, the length property of a built-in Function
+ object has the attributes { [[Writable]]: false, [[Enumerable]]: false,
+ [[Configurable]]: true }.
+includes: [propertyHelper.js]
---*/
-assert.sameValue(Object.assign.length, 2, "The length property of the assign method should be 2.");
+assert.sameValue(
+ Object.assign.length, 2, "The length property of the assign method should be 2."
+);
+
+verifyNotEnumerable(Object.assign, 'length');
+verifyNotWritable(Object.assign, 'length');
+verifyConfigurable(Object.assign, 'length');
diff --git a/test/built-ins/Object/assign/invoked-as-ctor.js b/test/built-ins/Object/assign/invoked-as-ctor.js
new file mode 100644
index 0000000000000000000000000000000000000000..cc2d0801ab5fb315022932db753e93a7d7767dda
--- /dev/null
+++ b/test/built-ins/Object/assign/invoked-as-ctor.js
@@ -0,0 +1,16 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 19.1.2.1
+description: Invoked as a constructor
+info: >
+ ES6 Section 9.3:
+
+ Built-in function objects that are not identified as constructors do not
+ implement the [[Construct]] internal method unless otherwise specified in
+ the description of a particular function.
+---*/
+
+assert.throws(TypeError, function() {
+ new Object.assign({});
+});
diff --git a/test/built-ins/Object/assign/name.js b/test/built-ins/Object/assign/name.js
new file mode 100644
index 0000000000000000000000000000000000000000..8970a427fec1c3907c8193098ee83897c30be083
--- /dev/null
+++ b/test/built-ins/Object/assign/name.js
@@ -0,0 +1,31 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 19.1.2.1
+description: '`name` property'
+info: >
+ ES6 Section 17:
+
+ Every built-in Function object, including constructors, that is not
+ identified as an anonymous function has a name property whose value is a
+ String. Unless otherwise specified, this value is the name that is given to
+ the function in this specification.
+
+ [...]
+
+ Unless otherwise specified, the name property of a built-in Function
+ object, if it exists, has the attributes { [[Writable]]: false,
+ [[Enumerable]]: false, [[Configurable]]: true }.
+includes: [propertyHelper.js]
+---*/
+
+assert.sameValue(
+ Object.assign.name,
+ 'assign',
+ 'The value of `Object.assign.name` is `"assign"`'
+);
+
+verifyNotEnumerable(Object.assign, 'name');
+verifyNotWritable(Object.assign, 'name');
+verifyConfigurable(Object.assign, 'name');
+
diff --git a/test/built-ins/Object/assign/source-get-attr-error.js b/test/built-ins/Object/assign/source-get-attr-error.js
new file mode 100644
index 0000000000000000000000000000000000000000..a18876bb7cb5046e5910529053ab17de24f4cbbe
--- /dev/null
+++ b/test/built-ins/Object/assign/source-get-attr-error.js
@@ -0,0 +1,25 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 19.1.2.1
+description: Errors thrown during retrieval of source object attributes
+info: >
+ [...]
+ 5. For each element nextSource of sources, in ascending index order,
+ [...]
+ c. Repeat for each element nextKey of keys in List order,
+ [...]
+ iii. if desc is not undefined and desc.[[Enumerable]] is true, then
+ 1. Let propValue be Get(from, nextKey).
+ 2. ReturnIfAbrupt(propValue).
+---*/
+
+var source = {
+ get attr() {
+ throw new Test262Error();
+ }
+};
+
+assert.throws(Test262Error, function() {
+ Object.assign({}, source);
+});
diff --git a/test/built-ins/Object/assign/source-non-enum.js b/test/built-ins/Object/assign/source-non-enum.js
new file mode 100644
index 0000000000000000000000000000000000000000..7ce053be1f5fab4ec1e446d4ad2a052b11d62d3c
--- /dev/null
+++ b/test/built-ins/Object/assign/source-non-enum.js
@@ -0,0 +1,25 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 19.1.2.1
+description: Does not assign non-enumerable source properties
+info: >
+ [...]
+ 5. For each element nextSource of sources, in ascending index order,
+ c. Repeat for each element nextKey of keys in List order,
+ i. Let desc be from.[[GetOwnProperty]](nextKey).
+ ii. ReturnIfAbrupt(desc).
+ iii. if desc is not undefined and desc.[[Enumerable]] is true, then
+---*/
+
+var target = {};
+var source = Object.defineProperty({}, 'attr', {
+ value: 1,
+ enumerable: false
+});
+var result;
+
+result = Object.assign(target, source);
+
+assert.sameValue(Object.hasOwnProperty.call(target, 'attr'), false);
+assert.sameValue(result, target);
diff --git a/test/built-ins/Object/assign/source-own-prop-desc-missing.js b/test/built-ins/Object/assign/source-own-prop-desc-missing.js
new file mode 100644
index 0000000000000000000000000000000000000000..1e51c464051fa223406e2afc0045570c108c24b5
--- /dev/null
+++ b/test/built-ins/Object/assign/source-own-prop-desc-missing.js
@@ -0,0 +1,35 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 19.1.2.1
+description: Invoked with a source which does not have a descriptor for an own property
+info: >
+ [...]
+ 5. For each element nextSource of sources, in ascending index order,
+ [...]
+ c. Repeat for each element nextKey of keys in List order,
+ i. Let desc be from.[[GetOwnProperty]](nextKey).
+ ii. ReturnIfAbrupt(desc).
+ iii. if desc is not undefined and desc.[[Enumerable]] is true, then
+features: [Proxy]
+---*/
+
+var callCount = 0;
+var target = {};
+var result;
+var source = new Proxy({}, {
+ ownKeys: function() {
+ callCount += 1;
+ return ['missing'];
+ }
+});
+
+result = Object.assign(target, source);
+
+assert.sameValue(callCount, 1, 'Proxy trap was invoked exactly once');
+assert.sameValue(
+ Object.hasOwnProperty.call(target, 'missing'),
+ false,
+ 'An own property was not created for a property without a property descriptor'
+);
+assert.sameValue(result, target);
diff --git a/test/built-ins/Object/assign/source-own-prop-error.js b/test/built-ins/Object/assign/source-own-prop-error.js
new file mode 100644
index 0000000000000000000000000000000000000000..ad4bef54f0e9737c5f3437fc3ba5a1d4f2f2ade6
--- /dev/null
+++ b/test/built-ins/Object/assign/source-own-prop-error.js
@@ -0,0 +1,24 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 19.1.2.1
+description: Invoked with a source whose own property descriptor cannot be retrieved
+info: >
+ [...]
+ 5. For each element nextSource of sources, in ascending index order,
+ [...]
+ c. Repeat for each element nextKey of keys in List order,
+ i. Let desc be from.[[GetOwnProperty]](nextKey).
+ ii. ReturnIfAbrupt(desc).
+features: [Proxy]
+---*/
+
+var source = new Proxy({ attr: null }, {
+ getOwnPropertyDescriptor: function() {
+ throw new Test262Error();
+ }
+});
+
+assert.throws(Test262Error, function() {
+ Object.assign({}, source);
+});
diff --git a/test/built-ins/Object/assign/source-own-prop-keys-error.js b/test/built-ins/Object/assign/source-own-prop-keys-error.js
new file mode 100644
index 0000000000000000000000000000000000000000..88912fa5a2b4d457951d8f0b2fb35183ab76e272
--- /dev/null
+++ b/test/built-ins/Object/assign/source-own-prop-keys-error.js
@@ -0,0 +1,26 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 19.1.2.1
+description: Invoked with a source whose own property keys cannot be retrieved
+info: >
+ [...]
+ 5. For each element nextSource of sources, in ascending index order,
+ a. If nextSource is undefined or null, let keys be an empty List.
+ b. Else,
+ i. Let from be ToObject(nextSource).
+ ii. ReturnIfAbrupt(from).
+ iii. Let keys be from.[[OwnPropertyKeys]]().
+ iv. ReturnIfAbrupt(keys).
+features: [Proxy]
+---*/
+
+var source = new Proxy({}, {
+ ownKeys: function() {
+ throw new Test262Error();
+ }
+});
+
+assert.throws(Test262Error, function() {
+ Object.assign({}, source);
+});
diff --git a/test/built-ins/Object/assign/target-set-not-writable.js b/test/built-ins/Object/assign/target-set-not-writable.js
new file mode 100644
index 0000000000000000000000000000000000000000..91f1d043628b768b1ea80acc7870a71f69f741ee
--- /dev/null
+++ b/test/built-ins/Object/assign/target-set-not-writable.js
@@ -0,0 +1,25 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 19.1.2.1
+description: Errors thrown during definition of target object attributes
+info: >
+ [...]
+ 5. For each element nextSource of sources, in ascending index order,
+ [...]
+ c. Repeat for each element nextKey of keys in List order,
+ [...]
+ iii. if desc is not undefined and desc.[[Enumerable]] is true, then
+ [...]
+ 3. Let status be Set(to, nextKey, propValue, true).
+ 4. ReturnIfAbrupt(status).
+---*/
+
+var target = {};
+Object.defineProperty(target, 'attr', {
+ writable: false
+});
+
+assert.throws(TypeError, function() {
+ Object.assign(target, { attr: 1 });
+});
diff --git a/test/built-ins/Object/assign/target-set-user-error.js b/test/built-ins/Object/assign/target-set-user-error.js
new file mode 100644
index 0000000000000000000000000000000000000000..1838ccc0cae91c71c6c6fffe57ceae62e5848240
--- /dev/null
+++ b/test/built-ins/Object/assign/target-set-user-error.js
@@ -0,0 +1,27 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 19.1.2.1
+description: Errors thrown during definition of target object attributes
+info: >
+ [...]
+ 5. For each element nextSource of sources, in ascending index order,
+ [...]
+ c. Repeat for each element nextKey of keys in List order,
+ [...]
+ iii. if desc is not undefined and desc.[[Enumerable]] is true, then
+ [...]
+ 3. Let status be Set(to, nextKey, propValue, true).
+ 4. ReturnIfAbrupt(status).
+---*/
+
+var target = {};
+Object.defineProperty(target, 'attr', {
+ set: function(_) {
+ throw new Test262Error();
+ }
+});
+
+assert.throws(Test262Error, function() {
+ Object.assign(target, { attr: 1 });
+});