Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

131 files changed, 4950 insertions, 0 deletions

diff --git a/js/src/tests/test262/built-ins/Promise/prototype/S25.4.4.2_A1.1_T1.js b/js/src/tests/test262/built-ins/Promise/prototype/S25.4.4.2_A1.1_T1.js
new file mode 100644
index 0000000000..3c08a74243
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/S25.4.4.2_A1.1_T1.js
@@ -0,0 +1,18 @@
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    Promise prototype object exists, is object, not enumerable, writable,
+    or configurable
+es6id: S25.4.4.2_A1.1_T1
+author: Sam Mikes
+description: Promise prototype exists
+---*/
+assert.notSameValue(
+  Promise.prototype,
+  undefined,
+  'The value of Promise.prototype is expected to not equal ``undefined``'
+);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/S25.4.5_A3.1_T1.js b/js/src/tests/test262/built-ins/Promise/prototype/S25.4.5_A3.1_T1.js
new file mode 100644
index 0000000000..5095976ce7
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/S25.4.5_A3.1_T1.js
@@ -0,0 +1,17 @@
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    Promise.prototype.constructor is the Promise constructor
+es6id: S25.4.5_A3.1_T1
+author: Sam Mikes
+description: Promise.prototype.constructor is the Promise constructor
+---*/
+assert.sameValue(
+  Promise.prototype.constructor,
+  Promise,
+  'The value of Promise.prototype.constructor is expected to equal the value of Promise'
+);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/Symbol.toStringTag.js b/js/src/tests/test262/built-ins/Promise/prototype/Symbol.toStringTag.js
new file mode 100644
index 0000000000..0d7d71d804
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/Symbol.toStringTag.js
@@ -0,0 +1,23 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 25.4.5.4
+description: >
+    `Symbol.toStringTag` property descriptor
+info: |
+    The initial value of the @@toStringTag property is the String value
+    "Promise".
+
+    This property has the attributes { [[Writable]]: false, [[Enumerable]]:
+    false, [[Configurable]]: true }.
+includes: [propertyHelper.js]
+features: [Symbol.toStringTag]
+---*/
+
+assert.sameValue(Promise.prototype[Symbol.toStringTag], 'Promise');
+
+verifyNotEnumerable(Promise.prototype, Symbol.toStringTag);
+verifyNotWritable(Promise.prototype, Symbol.toStringTag);
+verifyConfigurable(Promise.prototype, Symbol.toStringTag);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/browser.js b/js/src/tests/test262/built-ins/Promise/prototype/browser.js
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/browser.js
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/catch/S25.4.5.1_A1.1_T1.js b/js/src/tests/test262/built-ins/Promise/prototype/catch/S25.4.5.1_A1.1_T1.js
new file mode 100644
index 0000000000..0f145ac2b2
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/catch/S25.4.5.1_A1.1_T1.js
@@ -0,0 +1,16 @@
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    Promise prototype.catch is a function
+es6id: S25.4.5.1_A1.1_T1
+author: Sam Mikes
+description: Promise.prototype.catch is a function
+---*/
+assert(
+  !!(Promise.prototype.catch instanceof Function),
+  'The value of !!(Promise.prototype.catch instanceof Function) is expected to be true'
+);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/catch/S25.4.5.1_A2.1_T1.js b/js/src/tests/test262/built-ins/Promise/prototype/catch/S25.4.5.1_A2.1_T1.js
new file mode 100644
index 0000000000..efdf80c4a8
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/catch/S25.4.5.1_A2.1_T1.js
@@ -0,0 +1,19 @@
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    catch is a method on a Promise
+es6id: S25.4.5.1_A2.1_T1
+author: Sam Mikes
+description: catch is a method on a Promise
+---*/
+
+var p = Promise.resolve(3);
+
+assert(
+  !!(p.catch instanceof Function),
+  'The value of !!(p.catch instanceof Function) is expected to be true'
+);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/catch/S25.4.5.1_A3.1_T1.js b/js/src/tests/test262/built-ins/Promise/prototype/catch/S25.4.5.1_A3.1_T1.js
new file mode 100644
index 0000000000..415daf47ab
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/catch/S25.4.5.1_A3.1_T1.js
@@ -0,0 +1,22 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    catch(arg) is equivalent to then(undefined, arg)
+es6id: S25.4.5.1_A3.1_T1
+author: Sam Mikes
+description: catch is implemented in terms of then
+flags: [async]
+---*/
+
+var arg = {};
+
+var p = Promise.resolve(arg);
+
+p.catch(function() {
+  throw new Test262Error("Should not be called - promise is fulfilled");
+}).then(function(result) {
+  assert.sameValue(result, arg, 'The value of result is expected to equal the value of arg');
+}).then($DONE, $DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/catch/S25.4.5.1_A3.1_T2.js b/js/src/tests/test262/built-ins/Promise/prototype/catch/S25.4.5.1_A3.1_T2.js
new file mode 100644
index 0000000000..df555fd774
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/catch/S25.4.5.1_A3.1_T2.js
@@ -0,0 +1,22 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    catch(arg) is equivalent to then(undefined, arg)
+es6id: S25.4.5.1_A3.1_T2
+author: Sam Mikes
+description: catch is implemented in terms of then
+flags: [async]
+---*/
+
+var arg = {};
+
+var p = Promise.reject(arg);
+
+p.then(function() {
+  throw new Test262Error("Should not be called: did not expect promise to be fulfilled");
+}).catch(function(result) {
+  assert.sameValue(result, arg, 'The value of result is expected to equal the value of arg');
+}).then($DONE, $DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/catch/browser.js b/js/src/tests/test262/built-ins/Promise/prototype/catch/browser.js
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/catch/browser.js
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/catch/invokes-then.js b/js/src/tests/test262/built-ins/Promise/prototype/catch/invokes-then.js
new file mode 100644
index 0000000000..e02959e8db
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/catch/invokes-then.js
@@ -0,0 +1,54 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 25.4.5.1
+description: Promise.prototype.catch invokes `then` method
+info: |
+    1. Let promise be the this value.
+    2. Return Invoke(promise, "then", «undefined, onRejected»).
+---*/
+
+var target = {};
+var returnValue = {};
+var callCount = 0;
+var thisValue = null;
+var argCount = null;
+var firstArg = null;
+var secondArg = null;
+var result = null;
+
+target.then = function(a, b) {
+  callCount += 1;
+
+  thisValue = this;
+  argCount = arguments.length;
+  firstArg = a;
+  secondArg = b;
+
+  return returnValue;
+};
+
+result = Promise.prototype.catch.call(target, 1, 2, 3);
+
+assert.sameValue(callCount, 1, 'Invokes `then` method exactly once');
+assert.sameValue(
+  thisValue,
+  target,
+  'Invokes `then` method with the instance as the `this` value'
+);
+assert.sameValue(
+  argCount, 2, 'Invokes `then` method with exactly two single arguments'
+);
+assert.sameValue(
+  firstArg,
+  undefined,
+  'Invokes `then` method with `undefined` as the first argument'
+);
+assert.sameValue(
+  secondArg, 1, 'Invokes `then` method with the provided argument'
+);
+assert.sameValue(
+  result, returnValue, 'Returns the result of the invocation of `then`'
+);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/catch/length.js b/js/src/tests/test262/built-ins/Promise/prototype/catch/length.js
new file mode 100644
index 0000000000..1b487e62d9
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/catch/length.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: 25.4.5.1
+description: Promise.prototype.catch `length` property
+info: |
+    ES6 Section 17:
+    Every built-in Function object, including constructors, has a length
+    property whose value is an integer. Unless otherwise specified, this value
+    is equal to the largest number of named arguments shown in the subclause
+    headings for the function description, including optional parameters.
+
+    [...]
+
+    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(Promise.prototype.catch.length, 1);
+
+verifyNotEnumerable(Promise.prototype.catch, 'length');
+verifyNotWritable(Promise.prototype.catch, 'length');
+verifyConfigurable(Promise.prototype.catch, 'length');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/catch/name.js b/js/src/tests/test262/built-ins/Promise/prototype/catch/name.js
new file mode 100644
index 0000000000..25a93a3bb9
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/catch/name.js
@@ -0,0 +1,28 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 25.4.5.1
+description: Promise.prototype.catch `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(Promise.prototype.catch.name, 'catch');
+
+verifyNotEnumerable(Promise.prototype.catch, 'name');
+verifyNotWritable(Promise.prototype.catch, 'name');
+verifyConfigurable(Promise.prototype.catch, 'name');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/catch/not-a-constructor.js b/js/src/tests/test262/built-ins/Promise/prototype/catch/not-a-constructor.js
new file mode 100644
index 0000000000..2ff5558742
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/catch/not-a-constructor.js
@@ -0,0 +1,35 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-ecmascript-standard-built-in-objects
+description: >
+  Promise.prototype.catch does not implement [[Construct]], is not new-able
+info: |
+  ECMAScript Function Objects
+
+  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.
+
+  sec-evaluatenew
+
+  ...
+  7. If IsConstructor(constructor) is false, throw a TypeError exception.
+  ...
+includes: [isConstructor.js]
+features: [Reflect.construct, arrow-function]
+---*/
+
+assert.sameValue(
+  isConstructor(Promise.prototype.catch),
+  false,
+  'isConstructor(Promise.prototype.catch) must return false'
+);
+
+assert.throws(TypeError, () => {
+  let p = new Promise(() => {}); new p.catch();
+}, '`let p = new Promise(() => {}); new p.catch()` throws TypeError');
+
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/catch/prop-desc.js b/js/src/tests/test262/built-ins/Promise/prototype/catch/prop-desc.js
new file mode 100644
index 0000000000..2866aaa2d4
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/catch/prop-desc.js
@@ -0,0 +1,19 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 25.4.5.1
+description: Promise.prototype.catch property descriptor
+info: |
+    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]
+---*/
+
+assert.sameValue(typeof Promise.prototype.catch, 'function');
+
+verifyNotEnumerable(Promise.prototype, 'catch');
+verifyWritable(Promise.prototype, 'catch');
+verifyConfigurable(Promise.prototype, 'catch');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/catch/shell.js b/js/src/tests/test262/built-ins/Promise/prototype/catch/shell.js
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/catch/shell.js
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/catch/this-value-non-object.js b/js/src/tests/test262/built-ins/Promise/prototype/catch/this-value-non-object.js
new file mode 100644
index 0000000000..888c8b39f5
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/catch/this-value-non-object.js
@@ -0,0 +1,32 @@
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-promise.prototype.catch
+description: >
+  Promise.prototype.catch called with a non-object-coercible `this` value
+info: |
+  1. Let promise be the this value.
+  2. Return ? Invoke(promise, "then", «undefined, onRejected»).
+
+  7.3.18 Invoke
+
+  1. Assert: IsPropertyKey(P) is true.
+  2. If argumentsList was not passed, let argumentsList be a new empty List.
+  3. Let func be ? GetV(V, P).
+  4. Return ? Call(func, V, argumentsList).
+
+  7.3.2 GetV
+
+  1. Assert: IsPropertyKey(P) is true.
+  2. Let O be ? ToObject(V).
+---*/
+
+assert.throws(TypeError, function() {
+  Promise.prototype.catch.call(undefined);
+}, 'undefined');
+
+assert.throws(TypeError, function() {
+  Promise.prototype.catch.call(null);
+}, 'null');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/catch/this-value-obj-coercible.js b/js/src/tests/test262/built-ins/Promise/prototype/catch/this-value-obj-coercible.js
new file mode 100644
index 0000000000..4f71abec7a
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/catch/this-value-obj-coercible.js
@@ -0,0 +1,53 @@
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-promise.prototype.catch
+description: >
+  Promise.prototype.catch called with an object-coercible `this` value
+info: |
+  1. Let promise be the this value.
+  2. Return ? Invoke(promise, "then", «undefined, onRejected»).
+
+  7.3.18 Invoke
+
+  1. Assert: IsPropertyKey(P) is true.
+  2. If argumentsList was not passed, let argumentsList be a new empty List.
+  3. Let func be ? GetV(V, P).
+  4. Return ? Call(func, V, argumentsList).
+
+  7.3.2 GetV
+
+  1. Assert: IsPropertyKey(P) is true.
+  2. Let O be ? ToObject(V).
+features: [Symbol]
+---*/
+
+var booleanCount = 0;
+Boolean.prototype.then = function() {
+  booleanCount += 1;
+};
+Promise.prototype.catch.call(true);
+assert.sameValue(booleanCount, 1, 'boolean');
+
+var numberCount = 0;
+Number.prototype.then = function() {
+  numberCount += 1;
+};
+Promise.prototype.catch.call(34);
+assert.sameValue(numberCount, 1, 'number');
+
+var stringCount = 0;
+String.prototype.then = function() {
+  stringCount += 1;
+};
+Promise.prototype.catch.call('');
+assert.sameValue(stringCount, 1, 'string');
+
+var symbolCount = 0;
+Symbol.prototype.then = function() {
+  symbolCount += 1;
+};
+Promise.prototype.catch.call(Symbol());
+assert.sameValue(symbolCount, 1, 'symbol');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/catch/this-value-then-not-callable.js b/js/src/tests/test262/built-ins/Promise/prototype/catch/this-value-then-not-callable.js
new file mode 100644
index 0000000000..861f78bd9a
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/catch/this-value-then-not-callable.js
@@ -0,0 +1,75 @@
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-promise.prototype.catch
+description: >
+  Promise.prototype.catch called with a `this` value that does not define a
+  callable `this` property
+info: |
+  1. Let promise be the this value.
+  2. Return ? Invoke(promise, "then", «undefined, onRejected»).
+
+  7.3.18 Invoke
+
+  1. Assert: IsPropertyKey(P) is true.
+  2. If argumentsList was not passed, let argumentsList be a new empty List.
+  3. Let func be ? GetV(V, P).
+  4. Return ? Call(func, V, argumentsList).
+
+  7.3.2 GetV
+
+  1. Assert: IsPropertyKey(P) is true.
+  2. Let O be ? ToObject(V).
+  3. Return ? O.[[Get]](P, V).
+
+  7.3.12 Call (F, V [ , argumentsList ])
+
+  1. If argumentsList was not passed, let argumentsList be a new empty List.
+  2. If IsCallable(F) is false, throw a TypeError exception.
+  3. Return ? F.[[Call]](V, argumentsList).
+features: [Symbol]
+---*/
+
+var symbol = Symbol();
+
+assert.throws(TypeError, function() {
+  Promise.prototype.catch.call({});
+}, 'undefined');
+
+assert.throws(TypeError, function() {
+  Promise.prototype.catch.call({
+    then: null
+  });
+}, 'null');
+
+assert.throws(TypeError, function() {
+  Promise.prototype.catch.call({
+    then: 1
+  });
+}, 'number');
+
+assert.throws(TypeError, function() {
+  Promise.prototype.catch.call({
+    then: ''
+  });
+}, 'string');
+
+assert.throws(TypeError, function() {
+  Promise.prototype.catch.call({
+    then: true
+  });
+}, 'boolean');
+
+assert.throws(TypeError, function() {
+  Promise.prototype.catch.call({
+    then: symbol
+  });
+}, 'symbol');
+
+assert.throws(TypeError, function() {
+  Promise.prototype.catch.call({
+    then: {}
+  });
+}, 'ordinary object');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/catch/this-value-then-poisoned.js b/js/src/tests/test262/built-ins/Promise/prototype/catch/this-value-then-poisoned.js
new file mode 100644
index 0000000000..190776f246
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/catch/this-value-then-poisoned.js
@@ -0,0 +1,35 @@
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-promise.prototype.catch
+description: >
+  Promise.prototype.catch called with a `this` value whose `then` property is
+  an accessor property that returns an abrupt completion
+info: |
+  1. Let promise be the this value.
+  2. Return ? Invoke(promise, "then", «undefined, onRejected»).
+
+  7.3.18 Invoke
+
+  1. Assert: IsPropertyKey(P) is true.
+  2. If argumentsList was not passed, let argumentsList be a new empty List.
+  3. Let func be ? GetV(V, P).
+
+  7.3.2 GetV
+
+  1. Assert: IsPropertyKey(P) is true.
+  2. Let O be ? ToObject(V).
+  3. Return ? O.[[Get]](P, V).
+---*/
+
+var poisonedThen = Object.defineProperty({}, 'then', {
+  get: function() {
+    throw new Test262Error();
+  }
+});
+
+assert.throws(Test262Error, function() {
+  Promise.prototype.catch.call(poisonedThen);
+});
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/catch/this-value-then-throws.js b/js/src/tests/test262/built-ins/Promise/prototype/catch/this-value-then-throws.js
new file mode 100644
index 0000000000..39cd7cf5de
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/catch/this-value-then-throws.js
@@ -0,0 +1,42 @@
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-promise.prototype.catch
+description: >
+  Promise.prototype.catch called with a `this` value that defines a `then`
+  method which returns an abrupt completion.
+info: |
+  1. Let promise be the this value.
+  2. Return ? Invoke(promise, "then", «undefined, onRejected»).
+
+  7.3.18 Invoke
+
+  1. Assert: IsPropertyKey(P) is true.
+  2. If argumentsList was not passed, let argumentsList be a new empty List.
+  3. Let func be ? GetV(V, P).
+  4. Return ? Call(func, V, argumentsList).
+
+  7.3.2 GetV
+
+  1. Assert: IsPropertyKey(P) is true.
+  2. Let O be ? ToObject(V).
+  3. Return ? O.[[Get]](P, V).
+
+  7.3.12 Call (F, V [ , argumentsList ])
+
+  1. If argumentsList was not passed, let argumentsList be a new empty List.
+  2. If IsCallable(F) is false, throw a TypeError exception.
+  3. Return ? F.[[Call]](V, argumentsList).
+---*/
+
+var thrower = {
+  then: function() {
+    throw new Test262Error();
+  }
+};
+
+assert.throws(Test262Error, function() {
+  Promise.prototype.catch.call(thrower);
+});
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/browser.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/browser.js
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/browser.js
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/invokes-then-with-function.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/invokes-then-with-function.js
new file mode 100644
index 0000000000..c4597f9cb8
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/invokes-then-with-function.js
@@ -0,0 +1,69 @@
+// Copyright (C) 2017 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: Promise.prototype.finally invokes `then` method
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally, Reflect.construct, arrow-function]
+includes: [isConstructor.js]
+---*/
+
+var target = new Promise(function() {});
+var returnValue = {};
+var callCount = 0;
+var thisValue = null;
+var argCount = null;
+var resolve = null;
+var reject = null;
+
+target.then = function(a, b) {
+  callCount += 1;
+
+  thisValue = this;
+  argCount = arguments.length;
+  resolve = a;
+  reject = b;
+
+  return returnValue;
+};
+
+var originalFinallyHandler = function() {};
+var result = Promise.prototype.finally.call(target, originalFinallyHandler, 2, 3);
+
+assert.sameValue(callCount, 1, 'The value of `callCount` is 1');
+assert.sameValue(
+  thisValue,
+  target,
+  'The value of `thisValue` is expected to equal the value of target'
+);
+assert.sameValue(argCount, 2, 'The value of `argCount` is 2');
+assert.sameValue(
+  typeof resolve,
+  'function',
+  'The value of `typeof resolve` is "function"'
+);
+assert.notSameValue(resolve, originalFinallyHandler, 'The value of `resolve` is expected to not equal the value of `originalFinallyHandler`');
+assert.sameValue(resolve.length, 1, 'The value of resolve.length is 1');
+assert.sameValue(resolve.name, '', 'The value of resolve.name is ""');
+assert.sameValue(isConstructor(resolve), false, 'isConstructor(resolve) must return false');
+assert.throws(TypeError, () => {
+  new resolve();
+}, '`new resolve()` throws TypeError');
+
+
+assert.sameValue(
+  typeof reject,
+  'function',
+  'The value of `typeof reject` is "function"'
+);
+assert.notSameValue(reject, originalFinallyHandler, 'The value of `reject` is expected to not equal the value of `originalFinallyHandler`');
+assert.sameValue(reject.length, 1, 'The value of reject.length is 1');
+assert.sameValue(reject.name, '', 'The value of reject.name is ""');
+assert.sameValue(isConstructor(reject), false, 'isConstructor(reject) must return false');
+assert.throws(TypeError, () => {
+  new reject();
+}, '`new reject()` throws TypeError');
+
+assert.sameValue(result, returnValue, 'The value of `result` is expected to equal the value of returnValue');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/invokes-then-with-non-function.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/invokes-then-with-non-function.js
new file mode 100644
index 0000000000..ca7b36445c
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/invokes-then-with-non-function.js
@@ -0,0 +1,51 @@
+// Copyright (C) 2017 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: Promise.prototype.finally invokes `then` method
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+---*/
+
+var target = new Promise(function() {});
+var returnValue = {};
+var callCount = 0;
+var thisValue = null;
+var argCount = null;
+var firstArg = null;
+var secondArg = null;
+var result = null;
+
+target.then = function(a, b) {
+  callCount += 1;
+
+  thisValue = this;
+  argCount = arguments.length;
+  firstArg = a;
+  secondArg = b;
+
+  return returnValue;
+};
+
+result = Promise.prototype.finally.call(target, 1, 2, 3);
+
+assert.sameValue(callCount, 1, 'Invokes `then` method exactly once');
+assert.sameValue(
+  thisValue,
+  target,
+  'Invokes `then` method with the instance as the `this` value'
+);
+assert.sameValue(argCount, 2, 'Invokes `then` method with exactly two single arguments');
+assert.sameValue(
+  firstArg,
+  1,
+  'Invokes `then` method with the provided non-callable first argument'
+);
+assert.sameValue(
+  secondArg,
+  1,
+  'Invokes `then` method with the provided non-callable first argument'
+);
+assert.sameValue(result, returnValue, 'Returns the result of the invocation of `then`');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/is-a-function.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/is-a-function.js
new file mode 100644
index 0000000000..19abfde2fa
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/is-a-function.js
@@ -0,0 +1,22 @@
+// Copyright (C) 2017 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: Promise.prototype.finally is a function
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+---*/
+
+assert.sameValue(
+  Promise.prototype.finally instanceof Function,
+  true,
+  'Expected Promise.prototype.finally to be instanceof Function'
+);
+
+assert.sameValue(
+  typeof Promise.prototype.finally,
+  'function',
+  'Expected Promise.prototype.finally to be a function'
+);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/is-a-method.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/is-a-method.js
new file mode 100644
index 0000000000..741b127248
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/is-a-method.js
@@ -0,0 +1,18 @@
+// Copyright (C) 2017 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: finally is a method on a Promise
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+---*/
+
+var p = Promise.resolve(3);
+
+assert.sameValue(
+  p.finally,
+  Promise.prototype.finally,
+  'Expected the `finally` method on a Promise to be `Promise.prototype.finally`'
+);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/length.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/length.js
new file mode 100644
index 0000000000..1146a91f1d
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/length.js
@@ -0,0 +1,30 @@
+// Copyright (C) 2017 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: Promise.prototype.finally `length` property
+esid: sec-promise.prototype.finally
+info: |
+    ES6 Section 17:
+    Every built-in Function object, including constructors, has a length
+    property whose value is an integer. Unless otherwise specified, this value
+    is equal to the largest number of named arguments shown in the subclause
+    headings for the function description, including optional parameters.
+
+    [...]
+
+    Unless otherwise specified, the length property of a built-in Function
+    object has the attributes { [[Writable]]: false, [[Enumerable]]: false,
+    [[Configurable]]: true }.
+includes: [propertyHelper.js]
+features: [Promise.prototype.finally]
+---*/
+
+verifyProperty(Promise.prototype.finally, "length", {
+  value: 1,
+  enumerable: false,
+  configurable: true,
+  writable: false,
+});
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/name.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/name.js
new file mode 100644
index 0000000000..82020c1381
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/name.js
@@ -0,0 +1,30 @@
+// Copyright (C) 2017 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: Promise.prototype.finally `name` property
+esid: sec-promise.prototype.finally
+info: |
+    ES 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]
+features: [Promise.prototype.finally]
+---*/
+
+assert.sameValue(Promise.prototype.finally.name, 'finally');
+
+verifyNotEnumerable(Promise.prototype.finally, 'name');
+verifyNotWritable(Promise.prototype.finally, 'name');
+verifyConfigurable(Promise.prototype.finally, 'name');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/not-a-constructor.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/not-a-constructor.js
new file mode 100644
index 0000000000..25bb9a6554
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/not-a-constructor.js
@@ -0,0 +1,35 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-ecmascript-standard-built-in-objects
+description: >
+  Promise.prototype.finally does not implement [[Construct]], is not new-able
+info: |
+  ECMAScript Function Objects
+
+  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.
+
+  sec-evaluatenew
+
+  ...
+  7. If IsConstructor(constructor) is false, throw a TypeError exception.
+  ...
+includes: [isConstructor.js]
+features: [Reflect.construct, Promise.prototype.finally, arrow-function]
+---*/
+
+assert.sameValue(
+  isConstructor(Promise.prototype.finally),
+  false,
+  'isConstructor(Promise.prototype.finally) must return false'
+);
+
+assert.throws(TypeError, () => {
+  let p = new Promise(() => {}); new p.finally();
+}, '`let p = new Promise(() => {}); new p.finally()` throws TypeError');
+
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/prop-desc.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/prop-desc.js
new file mode 100644
index 0000000000..47d2f64fdd
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/prop-desc.js
@@ -0,0 +1,21 @@
+// Copyright (C) 2017 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: Promise.prototype.finally property descriptor
+esid: sec-promise.prototype.finally
+info: |
+    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: [Promise.prototype.finally]
+---*/
+
+assert.sameValue(typeof Promise.prototype.finally, 'function');
+
+verifyNotEnumerable(Promise.prototype, 'finally');
+verifyWritable(Promise.prototype, 'finally');
+verifyConfigurable(Promise.prototype, 'finally');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/rejected-observable-then-calls-PromiseResolve.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/rejected-observable-then-calls-PromiseResolve.js
new file mode 100644
index 0000000000..ecdbbdd164
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/rejected-observable-then-calls-PromiseResolve.js
@@ -0,0 +1,57 @@
+// |reftest| async
+// Copyright (C) 2020 Alexey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-catchfinallyfunctions
+description: >
+  PromiseResolve() avoids extra Promise capability creation.
+info: |
+  Catch Finally Functions
+
+  [...]
+  7. Let promise be ? PromiseResolve(C, result).
+  8. Let thrower be equivalent to a function that throws reason.
+  9. Return ? Invoke(promise, "then", « thrower »).
+
+  PromiseResolve ( C, x )
+
+  1. Assert: Type(C) is Object.
+  2. If IsPromise(x) is true, then
+    a. Let xConstructor be ? Get(x, "constructor").
+    b. If SameValue(xConstructor, C) is true, return x.
+features: [Promise.prototype.finally]
+flags: [async]
+---*/
+
+class MyPromise extends Promise {}
+
+var mp1Value = {};
+var mp1 = MyPromise.reject(mp1Value);
+var mp2 = MyPromise.reject(42);
+
+var thenCalls = [];
+var then = Promise.prototype.then;
+Promise.prototype.then = function(resolve, reject) {
+  thenCalls.push({promise: this, resolve, reject});
+  return then.call(this, resolve, reject);
+};
+
+mp1.finally(() => mp2).then(value => {
+  throw new Test262Error("Expected the promise to be rejected, got resolved with " + value);
+}, () => {
+  assert.sameValue(thenCalls.length, 5);
+
+  var mp2Calls = thenCalls.filter(c => c.promise === mp2);
+  assert.sameValue(mp2Calls.length, 1);
+  assert.sameValue(mp2Calls[0].reject, undefined);
+
+  var thrown = false;
+  try {
+    mp2Calls[0].resolve();
+  } catch (error) {
+    thrown = true;
+    assert.sameValue(error, mp1Value);
+  }
+
+  assert(thrown, "Expected resolve() to throw, but it didn't");
+}).then($DONE, $DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/rejected-observable-then-calls-argument.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/rejected-observable-then-calls-argument.js
new file mode 100644
index 0000000000..4d183bf248
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/rejected-observable-then-calls-argument.js
@@ -0,0 +1,69 @@
+// |reftest| async
+// Copyright (C) 2019 Alexey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-catchfinallyfunctions
+description: >
+  thrower is anonymous built-in function with length of 1 that throws reason.
+info: |
+  Catch Finally Functions
+
+  ...
+  8. Let thrower be equivalent to a function that throws reason.
+  9. Return ? Invoke(promise, "then", « thrower »).
+
+  The "length" property of a Catch Finally function is 1.
+features: [Promise.prototype.finally, Reflect.construct, class, arrow-function]
+includes: [isConstructor.js]
+flags: [async]
+---*/
+
+class MyError extends Error {}
+
+var myError = new MyError();
+Promise.reject(myError)
+  .finally(function() {})
+  .then(function(value) {
+    $DONE('Expected promise to be rejected, got fulfilled with ' + value);
+  }, function(reason) {
+    if (reason === myError) {
+      $DONE();
+    } else {
+      $DONE(reason);
+    }
+  });
+
+var calls = 0;
+var expected = [
+  { length: 0, name: '' },
+  { length: 1, name: '' }
+];
+
+var then = Promise.prototype.then;
+Promise.prototype.then = function(resolve, reject) {
+
+  assert.sameValue(
+    resolve.length,
+    expected[calls].length,
+    'The value of resolve.length is expected to equal the value of expected[calls].length'
+  );
+  assert.sameValue(
+    resolve.name,
+    expected[calls].name,
+    'The value of resolve.name is expected to equal the value of expected[calls].name'
+  );
+  if (calls === 0) {
+    assert.throws(MyError, resolve, '`resolve()` throws `MyError`');
+    assert.sameValue(arguments.length, 1, '`then` invoked with one argument');
+  } else {
+    assert.sameValue(isConstructor(reject), false, 'isConstructor(reject) must return false');
+    assert.throws(TypeError, () => {
+      new reject();
+    }, '`new reject()` throws TypeError');
+    assert.sameValue(arguments.length, 2, '`then` invoked with two arguments');
+  }
+
+  calls += 1;
+
+  return then.call(this, resolve, reject);
+};
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/rejected-observable-then-calls.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/rejected-observable-then-calls.js
new file mode 100644
index 0000000000..2d4dd9caaf
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/rejected-observable-then-calls.js
@@ -0,0 +1,40 @@
+// |reftest| async
+// Copyright (C) 2017 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: finally observably calls .then
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+flags: [async]
+includes: [promiseHelper.js]
+---*/
+var sequence = [];
+var noReason = {};
+var no = Promise.reject(noReason);
+no.then = function() {
+  sequence.push(1);
+  return Promise.prototype.then.apply(this, arguments);
+};
+
+var yesValue = {};
+var yes = Promise.resolve(yesValue);
+yes.then = function() {
+  sequence.push(4);
+  return Promise.prototype.then.apply(this, arguments);
+};
+
+no.catch(function(e) {
+  sequence.push(2);
+  assert.sameValue(e, noReason);
+  throw e;
+}).finally(function() {
+  sequence.push(3);
+  return yes;
+}).catch(function(e) {
+  sequence.push(5);
+  assert.sameValue(e, noReason);
+}).then(function() {
+  assert.sameValue(sequence.length, 5);
+  checkSequence(sequence, "All expected callbacks called in correct order");
+}).then($DONE, $DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/rejection-reason-no-fulfill.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/rejection-reason-no-fulfill.js
new file mode 100644
index 0000000000..3903e7778b
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/rejection-reason-no-fulfill.js
@@ -0,0 +1,30 @@
+// |reftest| async
+// Copyright (C) 2017 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: finally on a rejected promise can not convert to a fulfillment
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+flags: [async]
+includes: [promiseHelper.js]
+---*/
+var sequence = [];
+var original = {};
+var replacement = {};
+
+var p = Promise.reject(original);
+
+p.finally(function() {
+  sequence.push(1);
+  assert.sameValue(arguments.length, 0, 'onFinally receives zero args');
+  return replacement;
+}).then(function() {
+  throw new Test262Error('promise is rejected pre-finally; onFulfill should not be called');
+}).catch(function(reason) {
+  sequence.push(2);
+  assert.sameValue(reason, original, 'onFinally can not override the rejection value by returning');
+}).then(function() {
+  assert.sameValue(sequence.length, 2);
+  checkSequence(sequence, "All expected callbacks called in correct order");
+}).then($DONE, $DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/rejection-reason-override-with-throw.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/rejection-reason-override-with-throw.js
new file mode 100644
index 0000000000..66b6a468b3
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/rejection-reason-override-with-throw.js
@@ -0,0 +1,30 @@
+// |reftest| async
+// Copyright (C) 2017 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: finally on a rejected promise can override the rejection reason
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+flags: [async]
+includes: [promiseHelper.js]
+---*/
+var sequence = [];
+var original = {};
+var thrown = {};
+
+var p = Promise.reject(original);
+
+p.finally(function() {
+  sequence.push(1);
+  assert.sameValue(arguments.length, 0, 'onFinally receives zero args');
+  throw thrown;
+}).then(function() {
+  throw new Test262Error('promise is rejected; onFulfill should not be called');
+}).catch(function(reason) {
+  sequence.push(2);
+  assert.sameValue(reason, thrown, 'onFinally can override the rejection reason by throwing');
+}).then(function() {
+  assert.sameValue(sequence.length, 2);
+  checkSequence(sequence, "All expected callbacks called in correct order");
+}).then($DONE, $DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/resolution-value-no-override.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/resolution-value-no-override.js
new file mode 100644
index 0000000000..4951119385
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/resolution-value-no-override.js
@@ -0,0 +1,26 @@
+// |reftest| async
+// Copyright (C) 2017 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: finally on a fulfilled promise can not override the resolution value
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+flags: [async]
+includes: [promiseHelper.js]
+---*/
+var sequence = [];
+var obj = {};
+var p = Promise.resolve(obj);
+
+p.finally(function() {
+  sequence.push(1);
+  assert.sameValue(arguments.length, 0, 'onFinally receives zero args');
+  return {};
+}).then(function(x) {
+  sequence.push(2);
+  assert.sameValue(x, obj, 'onFinally can not override the resolution value');
+}).then(function() {
+  assert.sameValue(sequence.length, 2);
+  checkSequence(sequence, "All expected callbacks called in correct order");
+}).then($DONE, $DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/resolved-observable-then-calls-PromiseResolve.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/resolved-observable-then-calls-PromiseResolve.js
new file mode 100644
index 0000000000..137448ae6f
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/resolved-observable-then-calls-PromiseResolve.js
@@ -0,0 +1,46 @@
+// |reftest| async
+// Copyright (C) 2020 Alexey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-thenfinallyfunctions
+description: >
+  PromiseResolve() avoids extra Promise capability creation.
+info: |
+  Then Finally Functions
+
+  [...]
+  7. Let promise be ? PromiseResolve(C, result).
+  8. Let valueThunk be equivalent to a function that returns value.
+  9. Return ? Invoke(promise, "then", « valueThunk »).
+
+  PromiseResolve ( C, x )
+
+  1. Assert: Type(C) is Object.
+  2. If IsPromise(x) is true, then
+    a. Let xConstructor be ? Get(x, "constructor").
+    b. If SameValue(xConstructor, C) is true, return x.
+features: [Promise.prototype.finally]
+flags: [async]
+---*/
+
+class MyPromise extends Promise {}
+
+var mp1Value = {};
+var mp1 = MyPromise.resolve(mp1Value);
+var mp2 = MyPromise.resolve(42);
+
+var thenCalls = [];
+var then = Promise.prototype.then;
+Promise.prototype.then = function(resolve, reject) {
+  thenCalls.push({promise: this, resolve, reject});
+  return then.call(this, resolve, reject);
+};
+
+mp1.finally(() => mp2).then(() => {
+  assert.sameValue(thenCalls.length, 5);
+
+  var mp2Calls = thenCalls.filter(c => c.promise === mp2);
+  assert.sameValue(mp2Calls.length, 1);
+  assert.sameValue(mp2Calls[0].reject, undefined);
+  assert.sameValue(mp2Calls[0].resolve(), mp1Value);
+}).then($DONE, $DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/resolved-observable-then-calls-argument.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/resolved-observable-then-calls-argument.js
new file mode 100644
index 0000000000..ab7eedb192
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/resolved-observable-then-calls-argument.js
@@ -0,0 +1,55 @@
+// |reftest| async
+// Copyright (C) 2019 Alexey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-thenfinallyfunctions
+description: >
+  valueThunk is anonymous built-in function with length of 1 that returns value.
+info: |
+  Then Finally Functions
+
+  ...
+  8. Let valueThunk be equivalent to a function that returns value.
+  9. Return ? Invoke(promise, "then", « valueThunk »).
+
+  The "length" property of a Then Finally function is 1.
+features: [Promise.prototype.finally, Reflect.construct, arrow-function]
+includes: [isConstructor.js]
+flags: [async]
+---*/
+
+var value = {};
+
+Promise.resolve(value)
+  .finally(function() {})
+  .then(() => $DONE(), $DONE);
+
+var calls = 0;
+var expected = [
+  { length: 0, name: '' },
+  { length: 1, name: '' }
+];
+
+var then = Promise.prototype.then;
+Promise.prototype.then = function(resolve) {
+  assert.sameValue(isConstructor(resolve), false, 'isConstructor(resolve) must return false');
+  assert.throws(TypeError, () => {
+    new resolve();
+  }, '`new resolve()` throws TypeError');
+
+  assert.sameValue(
+    resolve.length,
+    expected[calls].length,
+    'The value of resolve.length is expected to equal the value of expected[calls].length'
+  );
+  assert.sameValue(
+    resolve.name,
+    expected[calls].name,
+    'The value of resolve.name is expected to equal the value of expected[calls].name'
+  );
+  if (calls === 0) {
+    assert.sameValue(resolve(), value, 'resolve() must return the value of value');
+  }
+  calls += 1;
+  return then.call(this, resolve);
+};
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/resolved-observable-then-calls.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/resolved-observable-then-calls.js
new file mode 100644
index 0000000000..4f2341bfb0
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/resolved-observable-then-calls.js
@@ -0,0 +1,40 @@
+// |reftest| async
+// Copyright (C) 2017 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: finally observably calls .then
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+flags: [async]
+includes: [promiseHelper.js]
+---*/
+var sequence = [];
+var yesValue = {};
+var yes = Promise.resolve(yesValue);
+yes.then = function() {
+  sequence.push(1);
+  return Promise.prototype.then.apply(this, arguments);
+};
+
+var noReason = {};
+var no = Promise.reject(noReason);
+no.then = function() {
+  sequence.push(4);
+  return Promise.prototype.then.apply(this, arguments);
+};
+
+yes.then(function(x) {
+  sequence.push(2);
+  assert.sameValue(x, yesValue);
+  return x;
+}).finally(function() {
+  sequence.push(3);
+  return no;
+}).catch(function(e) {
+  sequence.push(5);
+  assert.sameValue(e, noReason);
+}).then(function() {
+  assert.sameValue(sequence.length, 5);
+  checkSequence(sequence, "All expected callbacks called in correct order");
+}).then($DONE, $DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/shell.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/shell.js
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/shell.js
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/species-constructor.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/species-constructor.js
new file mode 100644
index 0000000000..00c1127836
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/species-constructor.js
@@ -0,0 +1,25 @@
+// |reftest| async
+// Copyright (C) 2017 V8. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Sathya Gunasekaran
+description: finally calls the SpeciesConstructor and creates the right amount of promises
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+flags: [async]
+---*/
+
+
+var count = 0;
+class FooPromise extends Promise {
+  constructor(resolve, reject) {
+    count++;
+    return super(resolve, reject);
+  }
+}
+
+new FooPromise(r => r())
+  .finally(() => {})
+  .then(() => {
+    assert.sameValue(count, 7, "7 new promises were created");
+  }).then($DONE, $DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/subclass-reject-count.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/subclass-reject-count.js
new file mode 100644
index 0000000000..6bf6504a22
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/subclass-reject-count.js
@@ -0,0 +1,24 @@
+// |reftest| async
+// Copyright (C) 2018 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: Promise subclass finally on rejected creates the proper number of subclassed promises
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+flags: [async]
+---*/
+
+var count = 0;
+class FooPromise extends Promise {
+  constructor(resolve, reject) {
+    count++;
+    return super(resolve, reject);
+  }
+}
+
+FooPromise.reject().finally(() => {}).then(value => {
+  throw new Test262Error("Expected Promise to be rejected, got: resolved with " + value);
+}, () => {
+  assert.sameValue(count, 7);
+}).then($DONE, $DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/subclass-resolve-count.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/subclass-resolve-count.js
new file mode 100644
index 0000000000..6af753fa66
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/subclass-resolve-count.js
@@ -0,0 +1,22 @@
+// |reftest| async
+// Copyright (C) 2018 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: Promise subclass finally on resolved creates the proper number of subclassed promises
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+flags: [async]
+---*/
+
+var count = 0;
+class FooPromise extends Promise {
+  constructor(resolve, reject) {
+    count++;
+    return super(resolve, reject);
+  }
+}
+
+FooPromise.resolve().finally(() => {}).then(() => {
+  assert.sameValue(count, 7);
+}).then($DONE, $DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/subclass-species-constructor-reject-count.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/subclass-species-constructor-reject-count.js
new file mode 100644
index 0000000000..9e9995fc91
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/subclass-species-constructor-reject-count.js
@@ -0,0 +1,21 @@
+// Copyright (C) 2018 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: finally on rejected Promise calls the SpeciesConstructor
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+---*/
+
+class FooPromise extends Promise {
+  static get[Symbol.species]() {
+    return Promise;
+  }
+}
+
+var p = Promise.reject().finally(() => FooPromise.reject());
+
+assert.sameValue(p instanceof Promise, true);
+assert.sameValue(p instanceof FooPromise, false);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/subclass-species-constructor-resolve-count.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/subclass-species-constructor-resolve-count.js
new file mode 100644
index 0000000000..e5049b7349
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/subclass-species-constructor-resolve-count.js
@@ -0,0 +1,21 @@
+// Copyright (C) 2018 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: finally on resolved Promise calls the SpeciesConstructor
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+---*/
+
+class FooPromise extends Promise {
+  static get[Symbol.species]() {
+    return Promise;
+  }
+}
+
+var p = Promise.resolve().finally(() => FooPromise.resolve());
+
+assert.sameValue(p instanceof Promise, true);
+assert.sameValue(p instanceof FooPromise, false);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-non-object.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-non-object.js
new file mode 100644
index 0000000000..8c9ec2e7bd
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-non-object.js
@@ -0,0 +1,21 @@
+// Copyright (C) 2017 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: >
+  Promise.prototype.finally called with a non-object-coercible `this` value
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+---*/
+
+assert.sameValue(typeof Promise.prototype.finally, 'function');
+
+assert.throws(TypeError, function() {
+  Promise.prototype.finally.call(undefined);
+}, 'undefined');
+
+assert.throws(TypeError, function() {
+  Promise.prototype.finally.call(null);
+}, 'null');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-proxy.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-proxy.js
new file mode 100644
index 0000000000..15ca9b1d7c
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-proxy.js
@@ -0,0 +1,21 @@
+// Copyright (C) 2018 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: >
+  Promise.prototype.finally called with a non-branded Promise does not throw
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+---*/
+
+var called = false;
+var p = new Proxy(Promise.resolve(), {});
+var oldThen = Promise.prototype.then;
+Promise.prototype.then = () => {
+  called = true;
+};
+Promise.prototype.finally.call(p);
+assert.sameValue(called, true);
+Promise.prototype.then = oldThen;
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-then-not-callable.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-then-not-callable.js
new file mode 100644
index 0000000000..ad5c687d6b
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-then-not-callable.js
@@ -0,0 +1,56 @@
+// Copyright (C) 2017 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: >
+  Promise.prototype.finally called with a `this` value that does not define a
+  callable `then` property
+esid: sec-promise.prototype.finally
+features: [Symbol, Promise.prototype.finally]
+---*/
+assert.sameValue(typeof Promise.prototype.finally, 'function');
+
+var symbol = Symbol();
+
+var thrower = function() {
+  throw new Test262Error('this should never happen');
+};
+
+var p = new Promise(function() {});
+
+p.then = undefined;
+assert.throws(TypeError, function() {
+  Promise.prototype.finally.call(p, thrower);
+}, 'undefined');
+
+p.then = null;
+assert.throws(TypeError, function() {
+  Promise.prototype.finally.call(p, thrower);
+}, 'null');
+
+p.then = 1;
+assert.throws(TypeError, function() {
+  Promise.prototype.finally.call(p, thrower);
+}, 'number');
+
+p.then = '';
+assert.throws(TypeError, function() {
+  Promise.prototype.finally.call(p, thrower);
+}, 'string');
+
+p.then = true;
+assert.throws(TypeError, function() {
+  Promise.prototype.finally.call(p, thrower);
+}, 'boolean');
+
+p.then = symbol;
+assert.throws(TypeError, function() {
+  Promise.prototype.finally.call(p, thrower);
+}, 'symbol');
+
+p.then = {};
+assert.throws(TypeError, function() {
+  Promise.prototype.finally.call(p, thrower);
+}, 'ordinary object');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-then-poisoned.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-then-poisoned.js
new file mode 100644
index 0000000000..44e4173989
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-then-poisoned.js
@@ -0,0 +1,26 @@
+// Copyright (C) 2017 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: >
+  Promise.prototype.finally called with a `this` value whose `then` property is
+  an accessor property that returns an abrupt completion
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+---*/
+
+var poisonedThen = Object.defineProperty(new Promise(function() {}), 'then', {
+  get: function() {
+    throw new Test262Error();
+  }
+});
+
+assert.throws(Test262Error, function() {
+  Promise.prototype.finally.call(poisonedThen);
+});
+
+assert.throws(Test262Error, function() {
+  poisonedThen.finally();
+});
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-then-throws.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-then-throws.js
new file mode 100644
index 0000000000..536ed24171
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-then-throws.js
@@ -0,0 +1,25 @@
+// Copyright (C) 2017 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+author: Jordan Harband
+description: >
+  Promise.prototype.finally called with a `this` value that defines a `then`
+  method which returns an abrupt completion.
+esid: sec-promise.prototype.finally
+features: [Promise.prototype.finally]
+---*/
+
+var thrower = new Promise(function() {});
+thrower.then = function() {
+  throw new Test262Error();
+};
+
+assert.throws(Test262Error, function() {
+  Promise.prototype.finally.call(thrower);
+});
+
+assert.throws(Test262Error, function() {
+  thrower.finally();
+});
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-thenable.js b/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-thenable.js
new file mode 100644
index 0000000000..dccb5be50c
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/finally/this-value-thenable.js
@@ -0,0 +1,19 @@
+// Copyright (C) 2019 Alexey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-promise.prototype.finally
+description: >
+  Promise.prototype.finally invoked on thenable returns result of "then" call.
+features: [Promise.prototype.finally]
+---*/
+
+var thenResult = {};
+var Thenable = function() {};
+Thenable.prototype.then = function() { return thenResult; };
+
+assert.sameValue(
+  Promise.prototype.finally.call(new Thenable()),
+  thenResult
+);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/no-promise-state.js b/js/src/tests/test262/built-ins/Promise/prototype/no-promise-state.js
new file mode 100644
index 0000000000..096249ac1d
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/no-promise-state.js
@@ -0,0 +1,28 @@
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-properties-of-the-promise-prototype-object
+description: Promise.prototype does not have a [[PromiseState]] internal slot
+info: |
+  The Promise prototype object is the intrinsic object %PromisePrototype%. The
+  value of the [[Prototype]] internal slot of the Promise prototype object is
+  the intrinsic object %ObjectPrototype%. The Promise prototype object is an
+  ordinary object. It does not have a [[PromiseState]] internal slot or any of
+  the other internal slots of Promise instances.
+
+  25.4.5.3 Promise.prototype.then
+
+  1. Let promise be the this value.
+  2. If IsPromise(promise) is false, throw a TypeError exception.
+
+  25.4.1.6 IsPromise
+
+  1. If Type(x) is not Object, return false.
+  2. If x does not have a [[PromiseState]] internal slot, return false.
+---*/
+
+assert.throws(TypeError, function() {
+  Promise.prototype.then.call(Promise.prototype, function() {}, function() {});
+});
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/prop-desc.js b/js/src/tests/test262/built-ins/Promise/prototype/prop-desc.js
new file mode 100644
index 0000000000..b369a731ad
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/prop-desc.js
@@ -0,0 +1,16 @@
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-promise.prototype
+description: Property descriptor of 'prototype' property
+info: |
+  This property has the attributes { [[Writable]]: false, [[Enumerable]]:
+  false, [[Configurable]]: false }.
+includes: [propertyHelper.js]
+---*/
+
+verifyNotEnumerable(Promise, 'prototype');
+verifyNotWritable(Promise, 'prototype');
+verifyNotConfigurable(Promise, 'prototype');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/proto.js b/js/src/tests/test262/built-ins/Promise/prototype/proto.js
new file mode 100644
index 0000000000..d0fb702c39
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/proto.js
@@ -0,0 +1,16 @@
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-properties-of-the-promise-prototype-object
+description: Promise.prototype [[Prototype]] is %ObjectPrototype%
+info: |
+  The Promise prototype object is the intrinsic object %PromisePrototype%. The
+  value of the [[Prototype]] internal slot of the Promise prototype object is
+  the intrinsic object %ObjectPrototype%. The Promise prototype object is an
+  ordinary object. It does not have a [[PromiseState]] internal slot or any of
+  the other internal slots of Promise instances.
+---*/
+
+assert.sameValue(Object.getPrototypeOf(Promise.prototype), Object.prototype);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/shell.js b/js/src/tests/test262/built-ins/Promise/prototype/shell.js
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/shell.js
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.4_A1.1_T1.js b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.4_A1.1_T1.js
new file mode 100644
index 0000000000..30133bb896
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.4_A1.1_T1.js
@@ -0,0 +1,42 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+   Misc sequencing tests
+   inspired by https://github.com/getify/native-promise-only/issues/34#issuecomment-54282002
+es6id: S25.4.2.1_A3.2_T2
+author: Sam Mikes
+description: Promise onResolved functions are called in predictable sequence
+includes: [promiseHelper.js]
+flags: [async]
+---*/
+
+var sequence = [];
+
+var p = new Promise(function(resolve, reject) {
+  sequence.push(1);
+  resolve("");
+});
+
+p.then(function() {
+  sequence.push(3);
+}).then(function() {
+  sequence.push(5);
+}).then(function() {
+  sequence.push(7);
+});
+
+p.then(function() {
+  sequence.push(4);
+}).then(function() {
+  sequence.push(6);
+}).then(function() {
+  sequence.push(8);
+}).then(function() {
+  assert.sameValue(sequence.length, 8);
+  checkSequence(sequence, "Sequence should be as expected");
+}).then($DONE, $DONE);
+
+sequence.push(2);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.4_A2.1_T1.js b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.4_A2.1_T1.js
new file mode 100644
index 0000000000..2b504506bb
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.4_A2.1_T1.js
@@ -0,0 +1,37 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+   Misc sequencing tests
+   inspired by https://github.com/promises-aplus/promises-tests/issues/61
+   Case "T1"
+es6id: S25.4.4_A2.1_T1
+author: Sam Mikes
+description: Promise onResolved functions are called in predictable sequence
+includes: [promiseHelper.js]
+flags: [async]
+---*/
+
+var resolveP1, rejectP2, sequence = [];
+
+(new Promise(function(resolve, reject) {
+  resolveP1 = resolve;
+})).then(function(msg) {
+  sequence.push(msg);
+}).then(function() {
+  assert.sameValue(sequence.length, 3);
+checkSequence(sequence, "Expected 1,2,3");
+}).then($DONE, $DONE);
+
+(new Promise(function(resolve, reject) {
+  rejectP2 = reject;
+})).catch(function(msg) {
+  sequence.push(msg);
+});
+
+rejectP2(2);
+resolveP1(3);
+
+sequence.push(1);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.4_A2.1_T2.js b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.4_A2.1_T2.js
new file mode 100644
index 0000000000..c689e07f99
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.4_A2.1_T2.js
@@ -0,0 +1,41 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+   Misc sequencing tests
+   inspired by https://github.com/promises-aplus/promises-tests/issues/61
+   Case "T2a"
+es6id: S25.4.4_A2.1_T2
+author: Sam Mikes
+description: Promise onResolved functions are called in predictable sequence
+includes: [promiseHelper.js]
+flags: [async]
+---*/
+
+var resolveP1, rejectP2, p1, p2,
+  sequence = [];
+
+p1 = new Promise(function(resolve, reject) {
+  resolveP1 = resolve;
+});
+p2 = new Promise(function(resolve, reject) {
+  rejectP2 = reject;
+});
+
+rejectP2(3);
+resolveP1(2);
+
+p1.then(function(msg) {
+  sequence.push(msg);
+});
+
+p2.catch(function(msg) {
+  sequence.push(msg);
+}).then(function() {
+  assert.sameValue(sequence.length, 3);
+  checkSequence(sequence, "Expected 1,2,3");
+}).then($DONE, $DONE);
+
+sequence.push(1);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.4_A2.1_T3.js b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.4_A2.1_T3.js
new file mode 100644
index 0000000000..dc1f0d7233
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.4_A2.1_T3.js
@@ -0,0 +1,43 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+   Misc sequencing tests
+   inspired by https://github.com/promises-aplus/promises-tests/issues/61
+   Case "T2b"
+es6id: S25.4.4_A2.1_T3
+author: Sam Mikes
+description: Promise onResolved functions are called in predictable sequence
+includes: [promiseHelper.js]
+flags: [async]
+---*/
+
+var resolveP1, rejectP2, p1, p2,
+  sequence = [];
+
+p1 = new Promise(function(resolve, reject) {
+  resolveP1 = resolve;
+});
+p2 = new Promise(function(resolve, reject) {
+  rejectP2 = reject;
+});
+
+rejectP2(3);
+resolveP1(2);
+
+Promise.resolve().then(function() {
+  p1.then(function(msg) {
+    sequence.push(msg);
+  });
+
+  p2.catch(function(msg) {
+    sequence.push(msg);
+  }).then(function() {
+    assert.sameValue(sequence.length, 3);
+    checkSequence(sequence, "Expected 1,2,3");
+  }).then($DONE, $DONE);
+});
+
+sequence.push(1);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A1.1_T1.js b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A1.1_T1.js
new file mode 100644
index 0000000000..959bc284dc
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A1.1_T1.js
@@ -0,0 +1,16 @@
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    Promise.prototype.then is a function of two arguments
+es6id: S25.4.5.3_A1.1_T1
+author: Sam Mikes
+description: Promise.prototype.then is a function of two arguments
+---*/
+assert(
+  !!(Promise.prototype.then instanceof Function),
+  'The value of !!(Promise.prototype.then instanceof Function) is expected to be true'
+);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A1.1_T2.js b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A1.1_T2.js
new file mode 100644
index 0000000000..c89023e083
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A1.1_T2.js
@@ -0,0 +1,17 @@
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    Promise.prototype.then is a function of two arguments
+es6id: S25.4.5.3_A1.1_T2
+author: Sam Mikes
+description: Promise.prototype.then is a function of two arguments
+---*/
+
+var p = new Promise(function() {});
+
+assert(!!(p.then instanceof Function), 'The value of !!(p.then instanceof Function) is expected to be true');
+assert.sameValue(p.then.length, 2, 'The value of p.then.length is expected to be 2');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A2.1_T1.js b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A2.1_T1.js
new file mode 100644
index 0000000000..a4e20bae96
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A2.1_T1.js
@@ -0,0 +1,18 @@
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    Promise.prototype.then expects a constructor conforming to Promise as 'this'
+es6id: S25.4.5.3_A2.1_T1
+author: Sam Mikes
+description: Promise.prototype.then throw if 'this' is non-Object
+---*/
+
+var p = new Promise(function() {});
+
+assert.throws(TypeError, function() {
+  p.then.call(3, function() {}, function() {});
+});
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A2.1_T2.js b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A2.1_T2.js
new file mode 100644
index 0000000000..4a982b5675
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A2.1_T2.js
@@ -0,0 +1,20 @@
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    Promise.prototype.then expects a Promise as 'this'
+es6id: S25.4.5.3_A2.1_T2
+author: Sam Mikes
+description: Promise.prototype.then throw if 'this' is non-Promise Object
+---*/
+
+function ZeroArgConstructor() {}
+
+var z = new ZeroArgConstructor();
+
+assert.throws(TypeError, function() {
+  Promise.then.call(z, function() {}, function() {});
+});
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A4.1_T1.js b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A4.1_T1.js
new file mode 100644
index 0000000000..8fc66ab964
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A4.1_T1.js
@@ -0,0 +1,21 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    PerformPromiseThen
+    Ref 25.4.5.3.1
+es6id: S25.4.5.3_A4.1_T1
+author: Sam Mikes
+description: Promise.prototype.then accepts 'undefined' as arg1, arg2
+flags: [async]
+---*/
+
+var arg = {};
+var p = Promise.resolve(arg);
+
+p.then(undefined, undefined)
+  .then(function(result) {
+  assert.sameValue(result, arg, 'The value of result is expected to equal the value of arg');
+}).then($DONE, $DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A4.1_T2.js b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A4.1_T2.js
new file mode 100644
index 0000000000..3aeca23d95
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A4.1_T2.js
@@ -0,0 +1,22 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    PerformPromiseThen
+    Ref 25.4.5.3.1
+es6id: S25.4.5.3_A4.1_T2
+author: Sam Mikes
+description: Promise.prototype.then accepts 'undefined' as arg1, arg2
+flags: [async]
+---*/
+
+var arg = {};
+var p = Promise.reject(arg);
+
+p.then(undefined, undefined).then(function() {
+  throw new Test262Error("Should not be called -- promise was rejected.");
+}, function(result) {
+  assert.sameValue(result, arg, 'The value of result is expected to equal the value of arg');
+}).then($DONE, $DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A4.2_T1.js b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A4.2_T1.js
new file mode 100644
index 0000000000..5b1ac21b27
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A4.2_T1.js
@@ -0,0 +1,21 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    PerformPromiseThen
+    Ref 25.4.5.3.1
+es6id: S25.4.5.3_A4.2_T1
+author: Sam Mikes
+description: Promise.prototype.then treats non-callable arg1, arg2 as undefined
+flags: [async]
+---*/
+
+var arg = {};
+var p = Promise.resolve(arg);
+
+p.then(3, 5)
+  .then(function(result) {
+  assert.sameValue(result, arg, 'The value of result is expected to equal the value of arg');
+}).then($DONE, $DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A4.2_T2.js b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A4.2_T2.js
new file mode 100644
index 0000000000..5efe836020
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A4.2_T2.js
@@ -0,0 +1,22 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    PerformPromiseThen
+    Ref 25.4.5.3.1
+es6id: S25.4.5.3_A4.2_T2
+author: Sam Mikes
+description: Promise.prototype.then treats non-callable arg1, arg2 as undefined
+flags: [async]
+---*/
+
+var arg = {};
+var p = Promise.reject(arg);
+
+p.then(3, 5).then(function() {
+  throw new Test262Error("Should not be called -- promise was rejected.");
+}, function(result) {
+  assert.sameValue(result, arg, 'The value of result is expected to equal the value of arg');
+}).then($DONE, $DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A5.1_T1.js b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A5.1_T1.js
new file mode 100644
index 0000000000..2f0b062fae
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A5.1_T1.js
@@ -0,0 +1,43 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    PerformPromiseThen
+    Ref 25.4.5.3.1
+es6id: S25.4.5.3_A5.1_T1
+author: Sam Mikes
+description: Promise.prototype.then enqueues handler if pending
+includes: [promiseHelper.js]
+flags: [async]
+---*/
+
+var sequence = [],
+  pResolve,
+  p = new Promise(function(resolve, reject) {
+    pResolve = resolve;
+  });
+
+sequence.push(1);
+
+p.then(function() {
+  sequence.push(3);
+  assert.sameValue(sequence.length, 3);
+  checkSequence(sequence, "Should be second");
+}).catch($DONE);
+
+Promise.resolve().then(function() {
+  // enqueue another then-handler
+  p.then(function() {
+    sequence.push(4);
+    assert.sameValue(sequence.length, 4);
+  checkSequence(sequence, "Should be third");
+  }).then($DONE, $DONE);
+
+  sequence.push(2);
+  assert.sameValue(sequence.length, 2);
+  checkSequence(sequence, "Should be first");
+
+  pResolve();
+}).catch($DONE);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A5.2_T1.js b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A5.2_T1.js
new file mode 100644
index 0000000000..6e09de73a1
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A5.2_T1.js
@@ -0,0 +1,45 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    PerformPromiseThen
+    Ref 25.4.5.3.1
+es6id: S25.4.5.3_A5.2_T1
+author: Sam Mikes
+description: Promise.prototype.then immediately queues handler if fulfilled
+includes: [promiseHelper.js]
+flags: [async]
+---*/
+
+var sequence = [],
+  pResolve,
+  p = new Promise(function(resolve, reject) {
+    pResolve = resolve;
+  });
+
+sequence.push(1);
+
+pResolve();
+
+p.then(function() {
+  sequence.push(3);
+  assert.sameValue(sequence.length, 3);
+checkSequence(sequence, "Should be first");
+}).catch($DONE);
+
+Promise.resolve().then(function() {
+  // enqueue another then-handler
+  p.then(function() {
+    sequence.push(5);
+    assert.sameValue(sequence.length, 5);
+checkSequence(sequence, "Should be third");
+  }).then($DONE, $DONE);
+
+  sequence.push(4);
+  assert.sameValue(sequence.length, 4);
+checkSequence(sequence, "Should be second");
+}).catch($DONE);
+
+sequence.push(2);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A5.3_T1.js b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A5.3_T1.js
new file mode 100644
index 0000000000..87a2b2271b
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/S25.4.5.3_A5.3_T1.js
@@ -0,0 +1,49 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    PerformPromiseThen
+    Ref 25.4.5.3.1
+es6id: S25.4.5.3_A5.3_T1
+author: Sam Mikes
+description: Promise.prototype.then immediately queues handler if rejected
+includes: [promiseHelper.js]
+flags: [async]
+---*/
+
+var sequence = [],
+  pReject,
+  p = new Promise(function(resolve, reject) {
+    pReject = reject;
+  });
+
+sequence.push(1);
+
+pReject();
+
+p.then(function() {
+  throw new Test262Error("Should not be called -- Promise rejected.");
+}, function() {
+  sequence.push(3);
+  assert.sameValue(sequence.length, 3, 'The value of sequence.length is expected to be 3');
+  checkSequence(sequence, "Should be first");
+}).catch($DONE);
+
+Promise.resolve().then(function() {
+  // enqueue another then-handler
+  p.then(function() {
+    throw new Test262Error("Should not be called (2) -- Promise rejected.");
+  }, function() {
+    sequence.push(5);
+    assert.sameValue(sequence.length, 5, 'The value of sequence.length is expected to be 5');
+  checkSequence(sequence, "Should be third");
+  }).then($DONE, $DONE);
+
+  sequence.push(4);
+  assert.sameValue(sequence.length, 4, 'The value of sequence.length is expected to be 4');
+  checkSequence(sequence, "Should be second");
+}).catch($DONE);
+
+sequence.push(2);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/browser.js b/js/src/tests/test262/built-ins/Promise/prototype/then/browser.js
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/browser.js
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/capability-executor-called-twice.js b/js/src/tests/test262/built-ins/Promise/prototype/then/capability-executor-called-twice.js
new file mode 100644
index 0000000000..de6cea8025
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/capability-executor-called-twice.js
@@ -0,0 +1,99 @@
+// Copyright (C) 2015 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+es6id: 25.4.5.3
+description: >
+  Throws a TypeError if capabilities executor already called with non-undefined values.
+info: |
+  Promise.prototype.then ( onFulfilled , onRejected )
+
+  ...
+  5. Let promiseCapability be NewPromiseCapability(C).
+  6. ReturnIfAbrupt(promiseCapability).
+  ...
+
+  25.4.1.5.1 GetCapabilitiesExecutor Functions
+    ...
+    3. If promiseCapability.[[Resolve]] is not undefined, throw a TypeError exception.
+    4. If promiseCapability.[[Reject]] is not undefined, throw a TypeError exception.
+    5. Set promiseCapability.[[Resolve]] to resolve.
+    6. Set promiseCapability.[[Reject]] to reject.
+    ...
+features: [class]
+---*/
+
+var constructorFunction;
+
+var promise = new class extends Promise {
+  constructor(executor) {
+    if (constructorFunction) {
+      constructorFunction(executor);
+      return {};
+    }
+    return super(executor);
+  }
+}(function() {});
+
+var checkPoint = "";
+constructorFunction = function(executor) {
+  checkPoint += "a";
+  executor();
+  checkPoint += "b";
+  executor(function() {}, function() {});
+  checkPoint += "c";
+};
+promise.then();
+assert.sameValue(checkPoint, "abc", "executor initially called with no arguments");
+
+var checkPoint = "";
+constructorFunction = function(executor) {
+  checkPoint += "a";
+  executor(undefined, undefined);
+  checkPoint += "b";
+  executor(function() {}, function() {});
+  checkPoint += "c";
+};
+promise.then();
+assert.sameValue(checkPoint, "abc", "executor initially called with (undefined, undefined)");
+
+var checkPoint = "";
+assert.throws(TypeError, function() {
+  constructorFunction = function(executor) {
+    checkPoint += "a";
+    executor(undefined, function() {});
+    checkPoint += "b";
+    executor(function() {}, function() {});
+    checkPoint += "c";
+  };
+  promise.then();
+}, "executor initially called with (undefined, function)");
+assert.sameValue(checkPoint, "ab", "executor initially called with (undefined, function)");
+
+var checkPoint = "";
+assert.throws(TypeError, function() {
+  constructorFunction = function(executor) {
+    checkPoint += "a";
+    executor(function() {}, undefined);
+    checkPoint += "b";
+    executor(function() {}, function() {});
+    checkPoint += "c";
+  };
+  promise.then();
+}, "executor initially called with (function, undefined)");
+assert.sameValue(checkPoint, "ab", "executor initially called with (function, undefined)");
+
+var checkPoint = "";
+assert.throws(TypeError, function() {
+  constructorFunction = function(executor) {
+    checkPoint += "a";
+    executor("invalid value", 123);
+    checkPoint += "b";
+    executor(function() {}, function() {});
+    checkPoint += "c";
+  };
+  promise.then();
+}, "executor initially called with (String, Number)");
+assert.sameValue(checkPoint, "ab", "executor initially called with (String, Number)");
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/capability-executor-not-callable.js b/js/src/tests/test262/built-ins/Promise/prototype/then/capability-executor-not-callable.js
new file mode 100644
index 0000000000..ed3dee89ae
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/capability-executor-not-callable.js
@@ -0,0 +1,104 @@
+// Copyright (C) 2015 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+es6id: 25.4.5.3
+description: >
+  Throws a TypeError if either resolve or reject capability is not callable.
+info: |
+  Promise.prototype.then ( onFulfilled , onRejected )
+
+  ...
+  5. Let promiseCapability be NewPromiseCapability(C).
+  6. ReturnIfAbrupt(promiseCapability).
+  ...
+
+  25.4.1.5 NewPromiseCapability ( C )
+    ...
+    4. Let executor be a new built-in function object as defined in GetCapabilitiesExecutor Functions (25.4.1.5.1).
+    5. Set the [[Capability]] internal slot of executor to promiseCapability.
+    6. Let promise be Construct(C, «executor»).
+    7. ReturnIfAbrupt(promise).
+    8. If IsCallable(promiseCapability.[[Resolve]]) is false, throw a TypeError exception.
+    9. If IsCallable(promiseCapability.[[Reject]]) is false, throw a TypeError exception.
+    ...
+features: [class]
+---*/
+
+var constructorFunction;
+
+var promise = new class extends Promise {
+  constructor(executor) {
+    if (constructorFunction) {
+      constructorFunction(executor);
+      return {};
+    }
+    return super(executor);
+  }
+}(function() {});
+
+var checkPoint = "";
+assert.throws(TypeError, function() {
+  constructorFunction = function(executor) {
+    checkPoint += "a";
+  };
+  promise.then();
+}, "executor not called at all");
+assert.sameValue(checkPoint, "a", "executor not called at all");
+
+var checkPoint = "";
+assert.throws(TypeError, function() {
+  constructorFunction = function(executor) {
+    checkPoint += "a";
+    executor();
+    checkPoint += "b";
+  };
+  promise.then();
+}, "executor called with no arguments");
+assert.sameValue(checkPoint, "ab", "executor called with no arguments");
+
+var checkPoint = "";
+assert.throws(TypeError, function() {
+  constructorFunction = function(executor) {
+    checkPoint += "a";
+    executor(undefined, undefined);
+    checkPoint += "b";
+  };
+  promise.then();
+}, "executor called with (undefined, undefined)");
+assert.sameValue(checkPoint, "ab", "executor called with (undefined, undefined)");
+
+var checkPoint = "";
+assert.throws(TypeError, function() {
+  constructorFunction = function(executor) {
+    checkPoint += "a";
+    executor(undefined, function() {});
+    checkPoint += "b";
+  };
+  promise.then();
+}, "executor called with (undefined, function)");
+assert.sameValue(checkPoint, "ab", "executor called with (undefined, function)");
+
+var checkPoint = "";
+assert.throws(TypeError, function() {
+  constructorFunction = function(executor) {
+    checkPoint += "a";
+    executor(function() {}, undefined);
+    checkPoint += "b";
+  };
+  promise.then();
+}, "executor called with (function, undefined)");
+assert.sameValue(checkPoint, "ab", "executor called with (function, undefined)");
+
+var checkPoint = "";
+assert.throws(TypeError, function() {
+  constructorFunction = function(executor) {
+    checkPoint += "a";
+    executor(123, "invalid value");
+    checkPoint += "b";
+  };
+  promise.then();
+}, "executor called with (Number, String)");
+assert.sameValue(checkPoint, "ab", "executor called with (Number, String)");
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/context-check-on-entry.js b/js/src/tests/test262/built-ins/Promise/prototype/then/context-check-on-entry.js
new file mode 100644
index 0000000000..794407fa72
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/context-check-on-entry.js
@@ -0,0 +1,26 @@
+// Copyright (C) 2015 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+es6id: 25.4.5.3
+description: >
+  Throws a TypeError if `this` is not a Promise object.
+info: |
+  Promise.prototype.then ( onFulfilled , onRejected )
+
+  1. Let promise be the this value.
+  2. If IsPromise(promise) is false, throw a TypeError exception.
+  ...
+---*/
+
+var object = {
+  get constructor() {
+    throw new Test262Error("get constructor called");
+  }
+};
+
+assert.throws(TypeError, function() {
+  Promise.prototype.then.call(object);
+});
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-access-count.js b/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-access-count.js
new file mode 100644
index 0000000000..9c54c46ac4
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-access-count.js
@@ -0,0 +1,52 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 25.4.5.3
+description: The instance's `constructor` property is accessed exactly once
+info: |
+    1. Let promise be the this value.
+    2. If IsPromise(promise) is false, throw a TypeError exception.
+    3. Let C be SpeciesConstructor(promise, %Promise%).
+    4. ReturnIfAbrupt(C).
+    5. Let resultCapability be NewPromiseCapability(C).
+    6. ReturnIfAbrupt(resultCapability).
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    7.3.20 SpeciesConstructor ( O, defaultConstructor )
+
+    1. Assert: Type(O) is Object.
+    2. Let C be Get(O, "constructor").
+    3. ReturnIfAbrupt(C).
+    4. If C is undefined, return defaultConstructor.
+    5. If Type(C) is not Object, throw a TypeError exception.
+    6. Let S be Get(C, @@species).
+    7. ReturnIfAbrupt(S).
+    8. If S is either undefined or null, return defaultConstructor.
+    9. If IsConstructor(S) is true, return S.
+    10. Throw a TypeError exception.
+flags: [async]
+---*/
+
+var callCount = 0;
+var prms = new Promise(function(resolve) {
+  resolve();
+});
+Object.defineProperty(prms, 'constructor', {
+  get: function() {
+    callCount += 1;
+    return Promise;
+  }
+});
+
+prms.then(function() {
+  if (callCount !== 1) {
+    $DONE('Expected constructor access count: 1. Actual: ' + callCount);
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-custom.js b/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-custom.js
new file mode 100644
index 0000000000..0ad80c7513
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-custom.js
@@ -0,0 +1,51 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 25.4.5.3
+description: The constructor defined by Symbol.species takes precedence
+info: |
+    1. Let promise be the this value.
+    2. If IsPromise(promise) is false, throw a TypeError exception.
+    3. Let C be SpeciesConstructor(promise, %Promise%).
+    4. ReturnIfAbrupt(C).
+    5. Let resultCapability be NewPromiseCapability(C).
+features: [Symbol.species, class]
+---*/
+
+var callCount = 0;
+var thisValue, firstArg, argLength, getCapabilitiesExecutor;
+var executor = function() {};
+var p1 = new Promise(function() {});
+var SpeciesConstructor = class extends Promise {
+  constructor(a) {
+    super(a);
+    callCount += 1;
+    thisValue = this;
+    getCapabilitiesExecutor = a;
+    argLength = arguments.length;
+  }
+};
+var p2;
+
+p1.constructor = function() {};
+p1.constructor[Symbol.species] = SpeciesConstructor;
+
+p2 = p1.then();
+
+assert.sameValue(callCount, 1, 'The constructor is invoked exactly once');
+assert(thisValue instanceof SpeciesConstructor);
+assert.sameValue(
+  argLength, 1, 'The constructor is invoked with a single argument'
+);
+assert.sameValue(typeof getCapabilitiesExecutor, 'function');
+assert.sameValue(
+  getCapabilitiesExecutor.length,
+  2,
+  'ES6 25.4.1.5.1: The length property of a GetCapabilitiesExecutor function is 2.'
+);
+assert(
+  p2 instanceof SpeciesConstructor,
+  'The returned object is an instance of the constructor'
+);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-null.js b/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-null.js
new file mode 100644
index 0000000000..a0b6df2a9e
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-null.js
@@ -0,0 +1,22 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 25.4.5.3
+description: >
+    A TypeError is thrown when the `this` value has a non-object `constructor` property
+info: |
+    1. Let promise be the this value.
+    2. If IsPromise(promise) is false, throw a TypeError exception.
+    3. Let C be SpeciesConstructor(promise, %Promise%).
+    4. ReturnIfAbrupt(C).
+    5. Let resultCapability be NewPromiseCapability(C).
+---*/
+
+var p = new Promise(function() {});
+p.constructor = null;
+
+assert.throws(TypeError, function() {
+  p.then();
+});
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-poisoned.js b/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-poisoned.js
new file mode 100644
index 0000000000..c0bb06362d
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-poisoned.js
@@ -0,0 +1,29 @@
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    Promise.prototype.then throws TypeError if Get(promise, "constructor") throws
+    Ref 25.4.5.3 step 4 ReturnIfAbrupt(C)
+es6id: S25.4.5.3_A3.1_T1
+author: Sam Mikes
+description: Promise.prototype.then throws if Get(promise, "constructor") throws
+---*/
+
+var p = Promise.resolve("foo");
+
+Object.defineProperty(p, "constructor", {
+  get: function() {
+    throw new Test262Error();
+  }
+});
+
+assert.throws(Test262Error, function() {
+  p.then(function() {
+    throw new Test262Error("Should never be called.");
+  }, function() {
+    throw new Test262Error("Should never be called.");
+  });
+});
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-throws.js b/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-throws.js
new file mode 100644
index 0000000000..d54621103e
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-throws.js
@@ -0,0 +1,45 @@
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: >
+    `Promise.prototype.then` invoked on a constructor value that throws an
+    error
+es6id: 25.4.5.3
+info: |
+    1. Let promise be the this value.
+    [...]
+    3. Let C be SpeciesConstructor(promise, %Promise%).
+    [...]
+    5. Let resultCapability be NewPromiseCapability(C).
+    6. ReturnIfAbrupt(resultCapability).
+
+    25.4.1.5 NewPromiseCapability
+    [...]
+    6. Let promise be Construct(C, «executor»).
+    7. ReturnIfAbrupt(promise).
+    features: [Symbol.species]
+---*/
+
+var BadCtor = function() {
+  throw new Test262Error();
+};
+var originalSpecies = Object.getOwnPropertyDescriptor(Promise, Symbol.species);
+
+Object.defineProperty(Promise, Symbol.species, {
+  value: BadCtor
+});
+
+try {
+  var p = new Promise(function(resolve) {
+    resolve();
+  });
+
+  assert.throws(Test262Error, function() {
+    p.then();
+  });
+} finally {
+  Object.defineProperty(Promise, Symbol.species, originalSpecies);
+}
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-undef.js b/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-undef.js
new file mode 100644
index 0000000000..513f9d6cb6
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/ctor-undef.js
@@ -0,0 +1,22 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 25.4.5.3
+description: >
+    The Promise built-in is used when the `this` value has no `constructor` property
+info: |
+    1. Let promise be the this value.
+    2. If IsPromise(promise) is false, throw a TypeError exception.
+    3. Let C be SpeciesConstructor(promise, %Promise%).
+    4. ReturnIfAbrupt(C).
+    5. Let resultCapability be NewPromiseCapability(C).
+---*/
+
+var p1 = new Promise(function() {});
+delete p1.constructor;
+
+var p2 = p1.then();
+
+assert(p2 instanceof Promise);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/deferred-is-resolved-value.js b/js/src/tests/test262/built-ins/Promise/prototype/then/deferred-is-resolved-value.js
new file mode 100644
index 0000000000..fd2f6f1cf5
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/deferred-is-resolved-value.js
@@ -0,0 +1,68 @@
+// |reftest| async
+// Copyright (C) 2015 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+es6id: 25.4.5.3
+description: >
+  Promise reaction jobs do not check for cyclic resolutions.
+info: |
+  Promise.prototype.then ( onFulfilled , onRejected )
+
+  ...
+  5. Let resultCapability be NewPromiseCapability(C).
+  6. ReturnIfAbrupt(resultCapability).
+  7. Return PerformPromiseThen(promise, onFulfilled, onRejected, resultCapability).
+
+  25.4.5.3.1 PerformPromiseThen ( promise, onFulfilled, onRejected, resultCapability )
+    ...
+    3. If IsCallable(onFulfilled) is false, then
+      a. Let onFulfilled be "Identity".
+    4. If IsCallable(onRejected) is false, then
+      a. Let onRejected be "Thrower".
+    5. Let fulfillReaction be the PromiseReaction { [[Capabilities]]: resultCapability, [[Handler]]: onFulfilled }.
+    6. Let rejectReaction be the PromiseReaction { [[Capabilities]]: resultCapability, [[Handler]]: onRejected}.
+    ...
+    8. Else if the value of promise's [[PromiseState]] internal slot is "fulfilled",
+      a. Let value be the value of promise's [[PromiseResult]] internal slot.
+      b. Perform EnqueueJob("PromiseJobs", PromiseReactionJob, «fulfillReaction, value»).
+    ...
+
+  25.4.2.1 PromiseReactionJob ( reaction, argument )
+    ...
+    4. If handler is "Identity", let handlerResult be NormalCompletion(argument).
+    ...
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined, «handlerResult.[[value]]»).
+    9. NextJob Completion(status).
+features: [class]
+flags: [async]
+---*/
+
+var createBadPromise = false;
+var object = {};
+
+class P extends Promise {
+  constructor(executor) {
+    if (createBadPromise) {
+      executor(
+        function(v) {
+          assert.sameValue(v, object);
+          $DONE();
+        },
+        function(e) {
+          $DONE(e);
+        }
+      );
+      return object;
+    }
+    return super(executor);
+  }
+}
+
+var p = P.resolve(object);
+
+createBadPromise = true;
+var q = p.then();
+createBadPromise = false;
+
+assert.sameValue(q, object, "then() returns object");
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/length.js b/js/src/tests/test262/built-ins/Promise/prototype/then/length.js
new file mode 100644
index 0000000000..1e865b0460
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/length.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: 25.4.5.3
+description: Promise.prototype.then `length` property
+info: |
+    ES6 Section 17:
+    Every built-in Function object, including constructors, has a length
+    property whose value is an integer. Unless otherwise specified, this value
+    is equal to the largest number of named arguments shown in the subclause
+    headings for the function description, including optional parameters.
+
+    [...]
+
+    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(Promise.prototype.then.length, 2);
+
+verifyNotEnumerable(Promise.prototype.then, 'length');
+verifyNotWritable(Promise.prototype.then, 'length');
+verifyConfigurable(Promise.prototype.then, 'length');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/name.js b/js/src/tests/test262/built-ins/Promise/prototype/then/name.js
new file mode 100644
index 0000000000..b1c97f9956
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/name.js
@@ -0,0 +1,28 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 25.4.5.3
+description: Promise.prototype.then `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(Promise.prototype.then.name, 'then');
+
+verifyNotEnumerable(Promise.prototype.then, 'name');
+verifyNotWritable(Promise.prototype.then, 'name');
+verifyConfigurable(Promise.prototype.then, 'name');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/not-a-constructor.js b/js/src/tests/test262/built-ins/Promise/prototype/then/not-a-constructor.js
new file mode 100644
index 0000000000..d943772f86
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/not-a-constructor.js
@@ -0,0 +1,35 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-ecmascript-standard-built-in-objects
+description: >
+  Promise.prototype.then does not implement [[Construct]], is not new-able
+info: |
+  ECMAScript Function Objects
+
+  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.
+
+  sec-evaluatenew
+
+  ...
+  7. If IsConstructor(constructor) is false, throw a TypeError exception.
+  ...
+includes: [isConstructor.js]
+features: [Reflect.construct, arrow-function]
+---*/
+
+assert.sameValue(
+  isConstructor(Promise.prototype.then),
+  false,
+  'isConstructor(Promise.prototype.then) must return false'
+);
+
+assert.throws(TypeError, () => {
+  let p = new Promise(() => {}); new p.then();
+}, '`let p = new Promise(() => {}); new p.then()` throws TypeError');
+
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/prfm-fulfilled.js b/js/src/tests/test262/built-ins/Promise/prototype/then/prfm-fulfilled.js
new file mode 100644
index 0000000000..89d5e2de5f
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/prfm-fulfilled.js
@@ -0,0 +1,36 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 25.4.5.3
+description: PerformPromiseThen on a fulfilled promise
+info: |
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+
+    [...]
+    8. Else if the value of promise's [[PromiseState]] internal slot is
+       "fulfilled",
+       a. Let value be the value of promise's [[PromiseResult]] internal slot.
+       b. Perform EnqueueJob("PromiseJobs", PromiseReactionJob,
+          «fulfillReaction, value»).
+    [...]
+flags: [async]
+---*/
+
+var value = {};
+var p = new Promise(function(resolve) {
+  resolve(value);
+});
+
+p.then(function(x) {
+  if (x !== value) {
+    $DONE('The `onFulfilled` handler should be invoked with the promise result.');
+    return;
+  }
+  $DONE();
+}, function() {
+  $DONE('The `onRejected` handler should not be invoked.');
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/prfm-pending-fulfulled.js b/js/src/tests/test262/built-ins/Promise/prototype/then/prfm-pending-fulfulled.js
new file mode 100644
index 0000000000..93204370cd
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/prfm-pending-fulfulled.js
@@ -0,0 +1,39 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 25.4.5.3
+description: PerformPromiseThen on a pending promise that is later fulfilled
+info: |
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+
+    [...]
+    7. If the value of promise's [[PromiseState]] internal slot is "pending",
+       a. Append fulfillReaction as the last element of the List that is the
+          value of promise's [[PromiseFulfillReactions]] internal slot.
+       b. Append rejectReaction as the last element of the List that is the
+          value of promise's [[PromiseRejectReactions]] internal slot.
+    [...]
+flags: [async]
+---*/
+
+var value = {};
+var resolve;
+var p = new Promise(function(_resolve) {
+  resolve = _resolve;
+});
+
+p.then(function(x) {
+  if (x !== value) {
+    $DONE('The `onFulfilled` handler should be invoked with the promise result.');
+    return;
+  }
+  $DONE();
+}, function() {
+  $DONE('The `onRejected` handler should not be invoked.');
+});
+
+resolve(value);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/prfm-pending-rejected.js b/js/src/tests/test262/built-ins/Promise/prototype/then/prfm-pending-rejected.js
new file mode 100644
index 0000000000..b65b5596ce
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/prfm-pending-rejected.js
@@ -0,0 +1,39 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 25.4.5.3
+description: PerformPromiseThen on a pending promise that is later rejected
+info: |
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+
+    [...]
+    7. If the value of promise's [[PromiseState]] internal slot is "pending",
+       a. Append fulfillReaction as the last element of the List that is the
+          value of promise's [[PromiseFulfillReactions]] internal slot.
+       b. Append rejectReaction as the last element of the List that is the
+          value of promise's [[PromiseRejectReactions]] internal slot.
+    [...]
+flags: [async]
+---*/
+
+var value = {};
+var reject;
+var p = new Promise(function(_, _reject) {
+  reject = _reject;
+});
+
+p.then(function() {
+  $DONE('The `onFulfilled` handler should not be invoked.');
+}, function(x) {
+  if (x !== value) {
+    $DONE('The `onRejected` handler should be invoked with the promise result.');
+    return;
+  }
+  $DONE();
+});
+
+reject(value);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/prfm-rejected.js b/js/src/tests/test262/built-ins/Promise/prototype/then/prfm-rejected.js
new file mode 100644
index 0000000000..4b74b5f3cb
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/prfm-rejected.js
@@ -0,0 +1,36 @@
+// |reftest| async
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 25.4.5.3
+description: PerformPromiseThen on a rejected promise
+info: |
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+
+    [...]
+    9. Else if the value of promise's [[PromiseState]] internal slot is
+       "rejected",
+       a. Let reason be the value of promise's [[PromiseResult]] internal slot.
+       b. Perform EnqueueJob("PromiseJobs", PromiseReactionJob,
+          «rejectReaction, reason»).
+    [...]
+flags: [async]
+---*/
+
+var value = {};
+var p = new Promise(function(_, reject) {
+  reject(value);
+});
+
+p.then(function() {
+  $DONE('The `onFulfilled` handler should not be invoked.');
+}, function(x) {
+  if (x !== value) {
+    $DONE('The `onRejected` handler should be invoked with the promise result.');
+    return;
+  }
+  $DONE();
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/prop-desc.js b/js/src/tests/test262/built-ins/Promise/prototype/then/prop-desc.js
new file mode 100644
index 0000000000..75e58c3117
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/prop-desc.js
@@ -0,0 +1,19 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 25.4.5.1
+description: Promise.prototype.then property descriptor
+info: |
+    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]
+---*/
+
+assert.sameValue(typeof Promise.prototype.then, 'function');
+
+verifyNotEnumerable(Promise.prototype, 'then');
+verifyWritable(Promise.prototype, 'then');
+verifyConfigurable(Promise.prototype, 'then');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/reject-pending-fulfilled.js b/js/src/tests/test262/built-ins/Promise/prototype/then/reject-pending-fulfilled.js
new file mode 100644
index 0000000000..7795f1bb2a
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/reject-pending-fulfilled.js
@@ -0,0 +1,49 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Rejecting from a pending promise that is later fulfilled
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    7. If the value of promise's [[PromiseState]] internal slot is "pending",
+       a. Append fulfillReaction as the last element of the List that is the
+          value of promise's [[PromiseFulfillReactions]] internal slot.
+       [...]
+
+    25.4.1.3.1 Promise Reject Functions
+    [...]
+    6. Return RejectPromise(promise, reason).
+flags: [async]
+---*/
+
+var resolve;
+var thenable = new Promise(function(_resolve) {
+  resolve = _resolve;
+});
+var p1 = new Promise(function(resolve) {
+  resolve();
+});
+var p2;
+
+p2 = p1.then(function() {
+  throw thenable;
+});
+
+p2.then(function() {
+  $DONE('The promise should not be fulfilled.');
+}, function(x) {
+  if (x !== thenable) {
+    $DONE('The promise should be rejected with the resolution value of the provided promise.');
+    return;
+  }
+
+  $DONE();
+});
+
+resolve();
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/reject-pending-rejected.js b/js/src/tests/test262/built-ins/Promise/prototype/then/reject-pending-rejected.js
new file mode 100644
index 0000000000..72c27c684c
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/reject-pending-rejected.js
@@ -0,0 +1,50 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Rejecting from a pending promise that is later rejected
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    7. If the value of promise's [[PromiseState]] internal slot is "pending",
+       [...]
+       b. Append rejectReaction as the last element of the List that is the
+          value of promise's [[PromiseRejectReactions]] internal slot.
+    [...]
+
+    25.4.1.3.1 Promise Reject Functions
+    [...]
+    6. Return RejectPromise(promise, reason).
+flags: [async]
+---*/
+
+var reject;
+var thenable = new Promise(function(resolve) {
+  resolve();
+});
+var p1 = new Promise(function(_, _reject) {
+  reject = _reject;
+});
+var p2;
+
+p2 = p1.then(function() {}, function() {
+  throw thenable;
+});
+
+p2.then(function() {
+  $DONE('The promise should not be fulfilled.');
+}, function(x) {
+  if (x !== thenable) {
+    $DONE('The promise should be rejected with the resolution value of the provided promise.');
+    return;
+  }
+
+  $DONE();
+});
+
+reject();
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/reject-settled-fulfilled.js b/js/src/tests/test262/built-ins/Promise/prototype/then/reject-settled-fulfilled.js
new file mode 100644
index 0000000000..56dbd6fff3
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/reject-settled-fulfilled.js
@@ -0,0 +1,54 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Rejecting from a fulfilled promise
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    8. Else if the value of promise's [[PromiseState]] internal slot is
+       "fulfilled",
+       a. Let value be the value of promise's [[PromiseResult]] internal slot.
+       b. EnqueueJob("PromiseJobs", PromiseReactionJob, «fulfillReaction,
+          value»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    7. If handlerResult is an abrupt completion, then
+       a. Let status be Call(promiseCapability.[[Reject]], undefined,
+          «handlerResult.[[value]]»).
+       [...]
+
+    25.4.1.3.1 Promise Reject Functions
+    [...]
+    6. Return RejectPromise(promise, reason).
+flags: [async]
+---*/
+
+var thenable = new Promise(function(resolve) {
+  resolve();
+});
+var p1 = new Promise(function(resolve) {
+  resolve();
+});
+var p2;
+
+p2 = p1.then(function() {
+  throw thenable;
+});
+
+p2.then(function() {
+  $DONE('The promise should not be fulfilled.');
+}, function(x) {
+  if (x !== thenable) {
+    $DONE('The promise should be rejected with the resolution value of the provided promise.');
+    return;
+  }
+
+  $DONE();
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/reject-settled-rejected.js b/js/src/tests/test262/built-ins/Promise/prototype/then/reject-settled-rejected.js
new file mode 100644
index 0000000000..0f87c6bb01
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/reject-settled-rejected.js
@@ -0,0 +1,54 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Rejecting from a rejected promise
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    9. Else if the value of promise's [[PromiseState]] internal slot is
+       "rejected",
+       a. Let reason be the value of promise's [[PromiseResult]] internal slot.
+       b. Perform EnqueueJob("PromiseJobs", PromiseReactionJob,
+          «rejectReaction, reason»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    7. If handlerResult is an abrupt completion, then
+       a. Let status be Call(promiseCapability.[[Reject]], undefined,
+          «handlerResult.[[value]]»).
+       [...]
+
+    25.4.1.3.1 Promise Reject Functions
+    [...]
+    6. Return RejectPromise(promise, reason).
+flags: [async]
+---*/
+
+var thenable = new Promise(function(resolve) {
+  resolve();
+});
+var p1 = new Promise(function(_, reject) {
+  reject();
+});
+var p2;
+
+p2 = p1.then(function() {}, function() {
+  throw thenable;
+});
+
+p2.then(function() {
+  $DONE('The promise should not be fulfilled.');
+}, function(x) {
+  if (x !== thenable) {
+    $DONE('The promise should be rejected with the resolution value of the provided promise.');
+    return;
+  }
+
+  $DONE();
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-non-obj.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-non-obj.js
new file mode 100644
index 0000000000..fd6602988b
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-non-obj.js
@@ -0,0 +1,46 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a non-object value from a pending promise that is later fulfilled
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    7. If the value of promise's [[PromiseState]] internal slot is "pending",
+       a. Append fulfillReaction as the last element of the List that is the
+          value of promise's [[PromiseFulfillReactions]] internal slot.
+       [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    7. If Type(resolution) is not Object, then
+       a. Return FulfillPromise(promise, resolution).
+flags: [async]
+---*/
+
+var resolve;
+var p1 = new Promise(function(_resolve) {
+  resolve = _resolve;
+});
+var p2;
+
+p2 = p1.then(function() {
+  return 23;
+});
+
+p2.then(function(value) {
+  if (value !== 23) {
+    $DONE('The promise should be fulfilled with the provided value.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
+
+resolve();
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-non-thenable.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-non-thenable.js
new file mode 100644
index 0000000000..e71b639f39
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-non-thenable.js
@@ -0,0 +1,54 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a non-thenable object value from a pending promise that is later fulfilled
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    7. If the value of promise's [[PromiseState]] internal slot is "pending",
+       a. Append fulfillReaction as the last element of the List that is the
+          value of promise's [[PromiseFulfillReactions]] internal slot.
+       [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    8. Let then be Get(resolution, "then").
+    9. If then is an abrupt completion, then
+       [...]
+    10. Let thenAction be then.[[value]].
+    11. If IsCallable(thenAction) is false, then
+        a. Return FulfillPromise(promise, resolution).
+flags: [async]
+---*/
+
+var nonThenable = {
+  then: null
+};
+var resolve;
+var p1 = new Promise(function(_resolve) {
+  resolve = _resolve;
+});
+var p2;
+
+p2 = p1.then(function() {
+  return nonThenable;
+});
+
+p2.then(function(value) {
+  if (value !== nonThenable) {
+    $DONE('The promise should be fulfilled with the provided value.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
+
+resolve();
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-poisoned-then.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-poisoned-then.js
new file mode 100644
index 0000000000..88c3cd57a5
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-poisoned-then.js
@@ -0,0 +1,54 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with an object with a "poisoned" `then` property from a pending promise that is later fulfilled
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    7. If the value of promise's [[PromiseState]] internal slot is "pending",
+       a. Append fulfillReaction as the last element of the List that is the
+          value of promise's [[PromiseFulfillReactions]] internal slot.
+       [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    8. Let then be Get(resolution, "then").
+    9. If then is an abrupt completion, then
+       a. Return RejectPromise(promise, then.[[value]]).
+flags: [async]
+---*/
+
+var value = {};
+var resolve;
+var poisonedThen = Object.defineProperty({}, 'then', {
+  get: function() {
+    throw value;
+  }
+});
+var p1 = new Promise(function(_resolve) {
+  resolve = _resolve;
+});
+var p2;
+
+p2 = p1.then(function() {
+  return poisonedThen;
+});
+
+p2.then(function(x) {
+  $DONE('The promise should not be fulfilled.');
+}, function(x) {
+  if (x !== value) {
+    $DONE('The promise should be rejected with the thrown exception.');
+    return;
+  }
+
+  $DONE();
+});
+
+resolve();
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-prms-cstm-then.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-prms-cstm-then.js
new file mode 100644
index 0000000000..147ce71f22
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-prms-cstm-then.js
@@ -0,0 +1,61 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a resolved Promise instance whose `then` method has been overridden from a pending promise that is later fulfilled
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    7. If the value of promise's [[PromiseState]] internal slot is "pending",
+       a. Append fulfillReaction as the last element of the List that is the
+          value of promise's [[PromiseFulfillReactions]] internal slot.
+       [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    8. Let then be Get(resolution, "then").
+    9. If then is an abrupt completion, then
+       [...]
+    10. Let thenAction be then.[[value]].
+    11. If IsCallable(thenAction) is false, then
+        [...]
+    12. Perform EnqueueJob ("PromiseJobs", PromiseResolveThenableJob,
+        «promise, resolution, thenAction»)
+flags: [async]
+---*/
+
+var value = {};
+var resolve;
+var thenable = new Promise(function(resolve) {
+  resolve();
+});
+var p1 = new Promise(function(_resolve) {
+  resolve = _resolve;
+});
+var p2;
+
+thenable.then = function(resolve) {
+  resolve(value);
+};
+
+p2 = p1.then(function() {
+  return thenable;
+});
+
+p2.then(function(x) {
+  if (x !== value) {
+    $DONE('The promise should be fulfilled with the resolution value of the provided promise.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
+
+resolve();
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-self.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-self.js
new file mode 100644
index 0000000000..1191706a68
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-self.js
@@ -0,0 +1,53 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a reference to the promise itself from a pending promise that is later fulfilled
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    7. If the value of promise's [[PromiseState]] internal slot is "pending",
+       a. Append fulfillReaction as the last element of the List that is the
+          value of promise's [[PromiseFulfillReactions]] internal slot.
+       [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    6. If SameValue(resolution, promise) is true, then
+       a. Let selfResolutionError be a newly created TypeError object.
+       b. Return RejectPromise(promise, selfResolutionError).
+flags: [async]
+---*/
+
+var resolve;
+var p1 = new Promise(function(_resolve) {
+  resolve = _resolve;
+});
+var p2;
+
+p2 = p1.then(function() {
+  return p2;
+});
+
+p2.then(function() {
+  $DONE('The promise should not be fulfilled.');
+}, function(reason) {
+  if (!reason) {
+    $DONE('The promise should be rejected with a value.');
+    return;
+  }
+
+  if (reason.constructor !== TypeError) {
+    $DONE('The promise should be rejected with a TypeError instance.');
+    return;
+  }
+
+  $DONE();
+});
+
+resolve();
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-thenable.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-thenable.js
new file mode 100644
index 0000000000..52ad8d2366
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-fulfilled-thenable.js
@@ -0,0 +1,57 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a thenable object value from a pending promise that is later fulfilled
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    7. If the value of promise's [[PromiseState]] internal slot is "pending",
+       a. Append fulfillReaction as the last element of the List that is the
+          value of promise's [[PromiseFulfillReactions]] internal slot.
+       [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    8. Let then be Get(resolution, "then").
+    9. If then is an abrupt completion, then
+       [...]
+    10. Let thenAction be then.[[value]].
+    11. If IsCallable(thenAction) is false, then
+        [...]
+    12. Perform EnqueueJob ("PromiseJobs", PromiseResolveThenableJob,
+        «promise, resolution, thenAction»)
+flags: [async]
+---*/
+
+var value = {};
+var resolve;
+var thenable = new Promise(function(resolve) {
+  resolve(value);
+});
+var p1 = new Promise(function(_resolve) {
+  resolve = _resolve;
+});
+var p2;
+
+p2 = p1.then(function() {
+  return thenable;
+});
+
+p2.then(function(x) {
+  if (x !== value) {
+    $DONE('The promise should be fulfilled with the resolution value of the provided promise.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
+
+resolve();
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-non-obj.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-non-obj.js
new file mode 100644
index 0000000000..1480ad1f5f
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-non-obj.js
@@ -0,0 +1,47 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a non-object value from a pending promise that is later rejected
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    7. If the value of promise's [[PromiseState]] internal slot is "pending",
+       [...]
+       b. Append rejectReaction as the last element of the List that is the
+          value of promise's [[PromiseRejectReactions]] internal slot.
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    7. If Type(resolution) is not Object, then
+       a. Return FulfillPromise(promise, resolution).
+flags: [async]
+---*/
+
+var reject;
+var p1 = new Promise(function(_, _reject) {
+  reject = _reject;
+});
+var p2;
+
+p2 = p1.then(function() {}, function() {
+  return 23;
+});
+
+p2.then(function(value) {
+  if (value !== 23) {
+    $DONE('The promise should be fulfilled with the provided value.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
+
+reject();
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-non-thenable.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-non-thenable.js
new file mode 100644
index 0000000000..19764d8de7
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-non-thenable.js
@@ -0,0 +1,55 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a non-thenable object value from a pending promise that is later rejected
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    7. If the value of promise's [[PromiseState]] internal slot is "pending",
+       [...]
+       b. Append rejectReaction as the last element of the List that is the
+          value of promise's [[PromiseRejectReactions]] internal slot.
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    8. Let then be Get(resolution, "then").
+    9. If then is an abrupt completion, then
+       [...]
+    10. Let thenAction be then.[[value]].
+    11. If IsCallable(thenAction) is false, then
+        a. Return FulfillPromise(promise, resolution).
+flags: [async]
+---*/
+
+var nonThenable = {
+  then: null
+};
+var reject;
+var p1 = new Promise(function(_, _reject) {
+  reject = _reject;
+});
+var p2;
+
+p2 = p1.then(function() {}, function() {
+  return nonThenable;
+});
+
+p2.then(function(value) {
+  if (value !== nonThenable) {
+    $DONE('The promise should be fulfilled with the provided value.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
+
+reject();
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-poisoned-then.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-poisoned-then.js
new file mode 100644
index 0000000000..542c6e7ead
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-poisoned-then.js
@@ -0,0 +1,55 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with an object with a "poisoned" `then` property from a pending promise that is later rejected
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    7. If the value of promise's [[PromiseState]] internal slot is "pending",
+       [...]
+       b. Append rejectReaction as the last element of the List that is the
+          value of promise's [[PromiseRejectReactions]] internal slot.
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    8. Let then be Get(resolution, "then").
+    9. If then is an abrupt completion, then
+       a. Return RejectPromise(promise, then.[[value]]).
+flags: [async]
+---*/
+
+var value = {};
+var reject;
+var poisonedThen = Object.defineProperty({}, 'then', {
+  get: function() {
+    throw value;
+  }
+});
+var p1 = new Promise(function(_, _reject) {
+  reject = _reject;
+});
+var p2;
+
+p2 = p1.then(function() {}, function() {
+  return poisonedThen;
+});
+
+p2.then(function(x) {
+  $DONE('The promise should not be fulfilled.');
+}, function(x) {
+  if (x !== value) {
+    $DONE('The promise should be rejected with the thrown exception.');
+    return;
+  }
+
+  $DONE();
+});
+
+reject();
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-prms-cstm-then.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-prms-cstm-then.js
new file mode 100644
index 0000000000..4a3fbc1674
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-prms-cstm-then.js
@@ -0,0 +1,62 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a resolved Promise instance whose `then` method has been overridden from a pending promise that is later rejected
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    7. If the value of promise's [[PromiseState]] internal slot is "pending",
+       [...]
+       b. Append rejectReaction as the last element of the List that is the
+          value of promise's [[PromiseRejectReactions]] internal slot.
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    8. Let then be Get(resolution, "then").
+    9. If then is an abrupt completion, then
+       [...]
+    10. Let thenAction be then.[[value]].
+    11. If IsCallable(thenAction) is false, then
+        [...]
+    12. Perform EnqueueJob ("PromiseJobs", PromiseResolveThenableJob,
+        «promise, resolution, thenAction»)
+flags: [async]
+---*/
+
+var value = {};
+var reject;
+var thenable = new Promise(function(resolve) {
+  resolve();
+});
+var p1 = new Promise(function(_, _reject) {
+  reject = _reject;
+});
+var p2;
+
+thenable.then = function(resolve) {
+  resolve(value);
+};
+
+p2 = p1.then(function() {}, function() {
+  return thenable;
+});
+
+p2.then(function(x) {
+  if (x !== value) {
+    $DONE('The promise should be fulfilled with the resolution value of the provided promise.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
+
+reject();
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-self.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-self.js
new file mode 100644
index 0000000000..7a31dc46bc
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-self.js
@@ -0,0 +1,54 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a reference to the promise itself from a pending promise that is later rejected
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    7. If the value of promise's [[PromiseState]] internal slot is "pending",
+       [...]
+       b. Append rejectReaction as the last element of the List that is the
+          value of promise's [[PromiseRejectReactions]] internal slot.
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    6. If SameValue(resolution, promise) is true, then
+       a. Let selfResolutionError be a newly created TypeError object.
+       b. Return RejectPromise(promise, selfResolutionError).
+flags: [async]
+---*/
+
+var reject;
+var p1 = new Promise(function(_, _reject) {
+  reject = _reject;
+});
+var p2;
+
+p2 = p1.then(function() {}, function() {
+  return p2;
+});
+
+p2.then(function() {
+  $DONE('The promise should not be fulfilled.');
+}, function(reason) {
+  if (!reason) {
+    $DONE('The promise should be rejected with a value.');
+    return;
+  }
+
+  if (reason.constructor !== TypeError) {
+    $DONE('The promise should be rejected with a TypeError instance.');
+    return;
+  }
+
+  $DONE();
+});
+
+reject();
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-thenable.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-thenable.js
new file mode 100644
index 0000000000..775bb1f79f
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-pending-rejected-thenable.js
@@ -0,0 +1,58 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a thenable object value from a pending promise that is later rejected
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    7. If the value of promise's [[PromiseState]] internal slot is "pending",
+       [...]
+       b. Append rejectReaction as the last element of the List that is the
+          value of promise's [[PromiseRejectReactions]] internal slot.
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    8. Let then be Get(resolution, "then").
+    9. If then is an abrupt completion, then
+       [...]
+    10. Let thenAction be then.[[value]].
+    11. If IsCallable(thenAction) is false, then
+        [...]
+    12. Perform EnqueueJob ("PromiseJobs", PromiseResolveThenableJob,
+        «promise, resolution, thenAction»)
+flags: [async]
+---*/
+
+var value = {};
+var reject;
+var thenable = new Promise(function(resolve) {
+  resolve(value);
+});
+var p1 = new Promise(function(_, _reject) {
+  reject = _reject;
+});
+var p2;
+
+p2 = p1.then(function() {}, function() {
+  return thenable;
+});
+
+p2.then(function(x) {
+  if (x !== value) {
+    $DONE('The promise should be fulfilled with the resolution value of the provided promise.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
+
+reject();
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-non-obj.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-non-obj.js
new file mode 100644
index 0000000000..5f6494fa3a
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-non-obj.js
@@ -0,0 +1,50 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a non-object value from a fulfilled promise
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    8. Else if the value of promise's [[PromiseState]] internal slot is
+       "fulfilled",
+       a. Let value be the value of promise's [[PromiseResult]] internal slot.
+       b. EnqueueJob("PromiseJobs", PromiseReactionJob, «fulfillReaction,
+          value»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    7. If Type(resolution) is not Object, then
+       a. Return FulfillPromise(promise, resolution).
+flags: [async]
+---*/
+
+var p1 = new Promise(function(resolve) {
+  resolve();
+});
+var p2;
+
+p2 = p1.then(function() {
+  return 23;
+});
+
+p2.then(function(value) {
+  if (value !== 23) {
+    $DONE('The promise should be fulfilled with the provided value.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-non-thenable.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-non-thenable.js
new file mode 100644
index 0000000000..3ca031489f
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-non-thenable.js
@@ -0,0 +1,58 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a non-thenable object value from a fulfilled promise
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    8. Else if the value of promise's [[PromiseState]] internal slot is
+       "fulfilled",
+       a. Let value be the value of promise's [[PromiseResult]] internal slot.
+       b. EnqueueJob("PromiseJobs", PromiseReactionJob, «fulfillReaction,
+          value»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    8. Let then be Get(resolution, "then").
+    9. If then is an abrupt completion, then
+       [...]
+    10. Let thenAction be then.[[value]].
+    11. If IsCallable(thenAction) is false, then
+        a. Return FulfillPromise(promise, resolution).
+flags: [async]
+---*/
+
+var nonThenable = {
+  then: null
+};
+var p1 = new Promise(function(resolve) {
+  resolve();
+});
+var p2;
+
+p2 = p1.then(function() {
+  return nonThenable;
+});
+
+p2.then(function(value) {
+  if (value !== nonThenable) {
+    $DONE('The promise should be fulfilled with the provided value.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-poisoned-then.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-poisoned-then.js
new file mode 100644
index 0000000000..ab5ee4a727
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-poisoned-then.js
@@ -0,0 +1,58 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with an object with a "poisoned" `then` property from a fulfilled promise
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    8. Else if the value of promise's [[PromiseState]] internal slot is
+       "fulfilled",
+       a. Let value be the value of promise's [[PromiseResult]] internal slot.
+       b. EnqueueJob("PromiseJobs", PromiseReactionJob, «fulfillReaction,
+          value»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    8. Let then be Get(resolution, "then").
+    9. If then is an abrupt completion, then
+       a. Return RejectPromise(promise, then.[[value]]).
+flags: [async]
+---*/
+
+var value = {};
+var poisonedThen = Object.defineProperty({}, 'then', {
+  get: function() {
+    throw value;
+  }
+});
+var p1 = new Promise(function(resolve) {
+  resolve();
+});
+var p2;
+
+p2 = p1.then(function() {
+  return poisonedThen;
+});
+
+p2.then(function(x) {
+  $DONE('The promise should not be fulfilled.');
+}, function(x) {
+  if (x !== value) {
+    $DONE('The promise should be rejected with the thrown exception.');
+    return;
+  }
+
+  $DONE();
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-prms-cstm-then.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-prms-cstm-then.js
new file mode 100644
index 0000000000..5594511e34
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-prms-cstm-then.js
@@ -0,0 +1,65 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a resolved Promise instance whose `then` method has been overridden from a fulfilled promise
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    8. Else if the value of promise's [[PromiseState]] internal slot is
+       "fulfilled",
+       a. Let value be the value of promise's [[PromiseResult]] internal slot.
+       b. EnqueueJob("PromiseJobs", PromiseReactionJob, «fulfillReaction,
+          value»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    8. Let then be Get(resolution, "then").
+    9. If then is an abrupt completion, then
+       [...]
+    10. Let thenAction be then.[[value]].
+    11. If IsCallable(thenAction) is false, then
+        [...]
+    12. Perform EnqueueJob ("PromiseJobs", PromiseResolveThenableJob,
+        «promise, resolution, thenAction»)
+flags: [async]
+---*/
+
+var value = {};
+var thenable = new Promise(function(resolve) {
+  resolve();
+});
+var p1 = new Promise(function(resolve) {
+  resolve();
+});
+var p2;
+
+thenable.then = function(resolve) {
+  resolve(value);
+};
+
+p2 = p1.then(function() {
+  return thenable;
+});
+
+p2.then(function(x) {
+  if (x !== value) {
+    $DONE('The promise should be fulfilled with the resolution value of the provided promise.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-self.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-self.js
new file mode 100644
index 0000000000..89c4f064b8
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-self.js
@@ -0,0 +1,57 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a reference to the promise itself from a fulfilled promise
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    8. Else if the value of promise's [[PromiseState]] internal slot is
+       "fulfilled",
+       a. Let value be the value of promise's [[PromiseResult]] internal slot.
+       b. EnqueueJob("PromiseJobs", PromiseReactionJob, «fulfillReaction,
+          value»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    6. If SameValue(resolution, promise) is true, then
+       a. Let selfResolutionError be a newly created TypeError object.
+       b. Return RejectPromise(promise, selfResolutionError).
+flags: [async]
+---*/
+
+var p1 = new Promise(function(resolve) {
+  resolve();
+});
+var p2;
+
+p2 = p1.then(function() {
+  return p2;
+});
+
+p2.then(function() {
+  $DONE('The promise should not be fulfilled.');
+}, function(reason) {
+  if (!reason) {
+    $DONE('The promise should be rejected with a value.');
+    return;
+  }
+
+  if (reason.constructor !== TypeError) {
+    $DONE('The promise should be rejected with a TypeError instance.');
+    return;
+  }
+
+  $DONE();
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-thenable.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-thenable.js
new file mode 100644
index 0000000000..f978984c36
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-fulfilled-thenable.js
@@ -0,0 +1,61 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a thenable object value from a fulfilled promise
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    8. Else if the value of promise's [[PromiseState]] internal slot is
+       "fulfilled",
+       a. Let value be the value of promise's [[PromiseResult]] internal slot.
+       b. EnqueueJob("PromiseJobs", PromiseReactionJob, «fulfillReaction,
+          value»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    8. Let then be Get(resolution, "then").
+    9. If then is an abrupt completion, then
+       [...]
+    10. Let thenAction be then.[[value]].
+    11. If IsCallable(thenAction) is false, then
+        [...]
+    12. Perform EnqueueJob ("PromiseJobs", PromiseResolveThenableJob,
+        «promise, resolution, thenAction»)
+flags: [async]
+---*/
+
+var value = {};
+var thenable = new Promise(function(resolve) {
+  resolve(value);
+});
+var p1 = new Promise(function(resolve) {
+  resolve();
+});
+var p2;
+
+p2 = p1.then(function() {
+  return thenable;
+});
+
+p2.then(function(x) {
+  if (x !== value) {
+    $DONE('The promise should be fulfilled with the resolution value of the provided promise.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-non-obj.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-non-obj.js
new file mode 100644
index 0000000000..1d39308386
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-non-obj.js
@@ -0,0 +1,50 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a non-object value from a rejected promise
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    9. Else if the value of promise's [[PromiseState]] internal slot is
+       "rejected",
+       a. Let reason be the value of promise's [[PromiseResult]] internal slot.
+       b. Perform EnqueueJob("PromiseJobs", PromiseReactionJob,
+          «rejectReaction, reason»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    7. If Type(resolution) is not Object, then
+       a. Return FulfillPromise(promise, resolution).
+flags: [async]
+---*/
+
+var p1 = new Promise(function(_, reject) {
+  reject();
+});
+var p2;
+
+p2 = p1.then(function() {}, function() {
+  return 23;
+});
+
+p2.then(function(value) {
+  if (value !== 23) {
+    $DONE('The promise should be fulfilled with the provided value.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-non-thenable.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-non-thenable.js
new file mode 100644
index 0000000000..eae6797f1a
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-non-thenable.js
@@ -0,0 +1,58 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a non-thenable object value from a rejected promise
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    9. Else if the value of promise's [[PromiseState]] internal slot is
+       "rejected",
+       a. Let reason be the value of promise's [[PromiseResult]] internal slot.
+       b. Perform EnqueueJob("PromiseJobs", PromiseReactionJob,
+          «rejectReaction, reason»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    8. Let then be Get(resolution, "then").
+    9. If then is an abrupt completion, then
+       [...]
+    10. Let thenAction be then.[[value]].
+    11. If IsCallable(thenAction) is false, then
+        a. Return FulfillPromise(promise, resolution).
+flags: [async]
+---*/
+
+var nonThenable = {
+  then: null
+};
+var p1 = new Promise(function(_, reject) {
+  reject();
+});
+var p2;
+
+p2 = p1.then(function() {}, function() {
+  return nonThenable;
+});
+
+p2.then(function(value) {
+  if (value !== nonThenable) {
+    $DONE('The promise should be fulfilled with the provided value.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-poisoned-then.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-poisoned-then.js
new file mode 100644
index 0000000000..2f33c820bb
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-poisoned-then.js
@@ -0,0 +1,58 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with an object with a "poisoned" `then` property from a rejected promise
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    9. Else if the value of promise's [[PromiseState]] internal slot is
+       "rejected",
+       a. Let reason be the value of promise's [[PromiseResult]] internal slot.
+       b. Perform EnqueueJob("PromiseJobs", PromiseReactionJob,
+          «rejectReaction, reason»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    8. Let then be Get(resolution, "then").
+    9. If then is an abrupt completion, then
+       a. Return RejectPromise(promise, then.[[value]]).
+flags: [async]
+---*/
+
+var value = {};
+var poisonedThen = Object.defineProperty({}, 'then', {
+  get: function() {
+    throw value;
+  }
+});
+var p1 = new Promise(function(_, reject) {
+  reject();
+});
+var p2;
+
+p2 = p1.then(function() {}, function() {
+  return poisonedThen;
+});
+
+p2.then(function(x) {
+  $DONE('The promise should not be fulfilled.');
+}, function(x) {
+  if (x !== value) {
+    $DONE('The promise should be rejected with the thrown exception.');
+    return;
+  }
+
+  $DONE();
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-prms-cstm-then.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-prms-cstm-then.js
new file mode 100644
index 0000000000..303a5315b0
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-prms-cstm-then.js
@@ -0,0 +1,65 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a resolved Promise instance whose `then` method has been overridden from a rejected promise
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    9. Else if the value of promise's [[PromiseState]] internal slot is
+       "rejected",
+       a. Let reason be the value of promise's [[PromiseResult]] internal slot.
+       b. Perform EnqueueJob("PromiseJobs", PromiseReactionJob,
+          «rejectReaction, reason»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    8. Let then be Get(resolution, "then").
+    9. If then is an abrupt completion, then
+       [...]
+    10. Let thenAction be then.[[value]].
+    11. If IsCallable(thenAction) is false, then
+        [...]
+    12. Perform EnqueueJob ("PromiseJobs", PromiseResolveThenableJob,
+        «promise, resolution, thenAction»)
+flags: [async]
+---*/
+
+var value = {};
+var thenable = new Promise(function(resolve) {
+  resolve();
+});
+var p1 = new Promise(function(_, reject) {
+  reject();
+});
+var p2;
+
+thenable.then = function(resolve) {
+  resolve(value);
+};
+
+p2 = p1.then(function() {}, function() {
+  return thenable;
+});
+
+p2.then(function(x) {
+  if (x !== value) {
+    $DONE('The promise should be fulfilled with the resolution value of the provided promise.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-self.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-self.js
new file mode 100644
index 0000000000..a585ca9b2e
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-self.js
@@ -0,0 +1,57 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a reference to the promise itself from a rejected promise
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    9. Else if the value of promise's [[PromiseState]] internal slot is
+       "rejected",
+       a. Let reason be the value of promise's [[PromiseResult]] internal slot.
+       b. Perform EnqueueJob("PromiseJobs", PromiseReactionJob,
+          «rejectReaction, reason»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    6. If SameValue(resolution, promise) is true, then
+       a. Let selfResolutionError be a newly created TypeError object.
+       b. Return RejectPromise(promise, selfResolutionError).
+flags: [async]
+---*/
+
+var p1 = new Promise(function(_, reject) {
+  reject();
+});
+var p2;
+
+p2 = p1.then(function() {}, function() {
+  return p2;
+});
+
+p2.then(function() {
+  $DONE('The promise should not be fulfilled.');
+}, function(reason) {
+  if (!reason) {
+    $DONE('The promise should be rejected with a value.');
+    return;
+  }
+
+  if (reason.constructor !== TypeError) {
+    $DONE('The promise should be rejected with a TypeError instance.');
+    return;
+  }
+
+  $DONE();
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-thenable.js b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-thenable.js
new file mode 100644
index 0000000000..827ff855f6
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/resolve-settled-rejected-thenable.js
@@ -0,0 +1,61 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Resolving with a thenable object value from a rejected promise
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    9. Else if the value of promise's [[PromiseState]] internal slot is
+       "rejected",
+       a. Let reason be the value of promise's [[PromiseResult]] internal slot.
+       b. Perform EnqueueJob("PromiseJobs", PromiseReactionJob,
+          «rejectReaction, reason»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    [...]
+
+    25.4.1.3.2 Promise Resolve Functions
+    [...]
+    8. Let then be Get(resolution, "then").
+    9. If then is an abrupt completion, then
+       [...]
+    10. Let thenAction be then.[[value]].
+    11. If IsCallable(thenAction) is false, then
+        [...]
+    12. Perform EnqueueJob ("PromiseJobs", PromiseResolveThenableJob,
+        «promise, resolution, thenAction»)
+flags: [async]
+---*/
+
+var value = {};
+var thenable = new Promise(function(resolve) {
+  resolve(value);
+});
+var p1 = new Promise(function(_, reject) {
+  reject();
+});
+var p2;
+
+p2 = p1.then(function() {}, function() {
+  return thenable;
+});
+
+p2.then(function(x) {
+  if (x !== value) {
+    $DONE('The promise should be fulfilled with the resolution value of the provided promise.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-invoke-nonstrict.js b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-invoke-nonstrict.js
new file mode 100644
index 0000000000..61fd431b65
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-invoke-nonstrict.js
@@ -0,0 +1,38 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    [...]
+    6. Else, let handlerResult be Call(handler, undefined, «argument»).
+es6id: S25.4.2.1_A3.1_T1
+author: Sam Mikes
+description: >
+    "fulfilled" handler invoked correctly outside of strict mode
+flags: [async, noStrict]
+---*/
+
+var expectedThis = this,
+  obj = {};
+
+var p = Promise.resolve(obj).then(function(arg) {
+  if (this !== expectedThis) {
+    $DONE("'this' must be global object, got " + this);
+    return;
+  }
+
+  if (arg !== obj) {
+    $DONE("Expected promise to be fulfilled by obj, actually " + arg);
+    return;
+  }
+
+  if (arguments.length !== 1) {
+    $DONE('Expected handler function to be called with exactly 1 argument.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-invoke-strict-strict.js b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-invoke-strict-strict.js
new file mode 100644
index 0000000000..3c0ab9a54d
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-invoke-strict-strict.js
@@ -0,0 +1,39 @@
+// |reftest| async
+'use strict';
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    [...]
+    6. Else, let handlerResult be Call(handler, undefined, «argument»).
+es6id: S25.4.2.1_A3.1_T2
+author: Sam Mikes
+description: >
+    "fulfilled" handler invoked correctly in strict mode
+flags: [async, onlyStrict]
+---*/
+
+var expectedThis = undefined,
+  obj = {};
+
+var p = Promise.resolve(obj).then(function(arg) {
+  if (this !== expectedThis) {
+    $DONE("'this' must be undefined, got " + this);
+    return;
+  }
+
+  if (arg !== obj) {
+    $DONE("Expected promise to be fulfilled by obj, actually " + arg);
+    return;
+  }
+
+  if (arguments.length !== 1) {
+    $DONE('Expected handler function to be called with exactly 1 argument.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The promise should not be rejected.');
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-next-abrupt.js b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-next-abrupt.js
new file mode 100644
index 0000000000..ec9ab0172b
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-next-abrupt.js
@@ -0,0 +1,46 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Abrupt completions should not preclude additional jobs
+es6id: 25.4.2.1
+info: |
+    [...]
+    7. If handlerResult is an abrupt completion, then
+       a. Let status be Call(promiseCapability.[[Reject]], undefined,
+          «handlerResult.[[value]]»).
+       b. NextJob Completion(status).
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    9. NextJob Completion(status).
+flags: [async]
+---*/
+
+var promise = new Promise(function(resolve) {
+  resolve();
+});
+var fulfilledCallCount = 0;
+var rejectedCallCount = 0;
+
+promise.then(function() {
+  fulfilledCallCount += 1;
+  throw new Error();
+}, function() {
+  rejectedCallCount += 1;
+});
+
+promise.then(function() {
+  if (fulfilledCallCount !== 1) {
+    $DONE('Expected "onFulfilled" handler to be invoked exactly once.');
+    return;
+  }
+
+  if (rejectedCallCount !== 0) {
+    $DONE('Expected "onRejected" handler to not be invoked.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('This promise should not be rejected.');
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-next.js b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-next.js
new file mode 100644
index 0000000000..13fb4ca62f
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-next.js
@@ -0,0 +1,54 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: All queued jobs should be executed in series
+es6id: 25.4.2.1
+info: |
+    [...]
+    7. If handlerResult is an abrupt completion, then
+       a. Let status be Call(promiseCapability.[[Reject]], undefined,
+          «handlerResult.[[value]]»).
+       b. NextJob Completion(status).
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    9. NextJob Completion(status).
+flags: [async]
+---*/
+
+var promise = new Promise(function(resolve) {
+  resolve();
+});
+var log = '';
+
+promise.then(function() {
+  log += 'a';
+}, function() {
+  log += 'A';
+});
+
+promise.then(function() {
+  log += 'b';
+}, function() {
+  log += 'B';
+});
+
+promise.then(function() {
+  log += 'c';
+}, function() {
+  log += 'C';
+});
+
+promise.then(function() {
+  if (log !== 'abc') {
+    $DONE(
+      'Expected each "onFulfilled" handler to be invoked exactly once in series. ' +
+      'Expected: abc. Actual: ' + log
+    );
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('This promise should not be rejected.');
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-return-abrupt.js b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-return-abrupt.js
new file mode 100644
index 0000000000..a394847ce9
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-return-abrupt.js
@@ -0,0 +1,51 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: An abrupt completion should trigger promise rejection
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    8. Else if the value of promise's [[PromiseState]] internal slot is
+       "fulfilled",
+       a. Let value be the value of promise's [[PromiseResult]] internal slot.
+       b. EnqueueJob("PromiseJobs", PromiseReactionJob, «fulfillReaction,
+          value»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    7. If handlerResult is an abrupt completion, then
+       a. Let status be Call(promiseCapability.[[Reject]], undefined,
+          «handlerResult.[[value]]»).
+       b. NextJob Completion(status).
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    9. NextJob Completion(status).
+flags: [async]
+---*/
+
+var value = {};
+var p1 = new Promise(function(resolve) {
+  resolve();
+});
+var p2;
+
+p2 = p1.then(function() {
+  throw value;
+}, function() {});
+
+p2.then(function() {
+  $DONE('The `onFulfilled` handler should not be invoked.');
+}, function(x) {
+  if (x !== value) {
+    $DONE('The `onRejected` handler should be invoked with the promise result.');
+    return;
+  }
+
+  $DONE();
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-return-normal.js b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-return-normal.js
new file mode 100644
index 0000000000..5acd838f06
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-fulfilled-return-normal.js
@@ -0,0 +1,51 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: A normal completion should trigger promise fulfillment
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    8. Else if the value of promise's [[PromiseState]] internal slot is
+       "fulfilled",
+       a. Let value be the value of promise's [[PromiseResult]] internal slot.
+       b. EnqueueJob("PromiseJobs", PromiseReactionJob, «fulfillReaction,
+          value»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    7. If handlerResult is an abrupt completion, then
+       a. Let status be Call(promiseCapability.[[Reject]], undefined,
+          «handlerResult.[[value]]»).
+       b. NextJob Completion(status).
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    9. NextJob Completion(status).
+flags: [async]
+---*/
+
+var value = {};
+var p1 = new Promise(function(resolve) {
+  resolve();
+});
+var p2;
+
+p2 = p1.then(function() {
+  return value;
+}, function() {});
+
+p2.then(function(x) {
+  if (x !== value) {
+    $DONE('The `onFulfilled` handler should be invoked with the promise result.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The `onRejected` handler should not be invoked.');
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-identity.js b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-identity.js
new file mode 100644
index 0000000000..d559176177
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-identity.js
@@ -0,0 +1,25 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    Promise reaction jobs have predictable environment
+es6id: S25.4.2.1_A1.1_T1
+author: Sam Mikes
+description: argument passes through "Identity"
+flags: [async]
+---*/
+
+var obj = {};
+
+var p = Promise.resolve(obj).then( /*Identity, Thrower*/ )
+  .then(function(arg) {
+    if (arg !== obj) {
+      $DONE("Expected promise to be fulfilled with obj, actually " + arg);
+      return;
+    }
+    $DONE();
+  }, function() {
+    $DONE('The promise should not be rejected.');
+  });
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-invoke-nonstrict.js b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-invoke-nonstrict.js
new file mode 100644
index 0000000000..0b548a01f5
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-invoke-nonstrict.js
@@ -0,0 +1,38 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    [...]
+    6. Else, let handlerResult be Call(handler, undefined, «argument»).
+es6id: S25.4.2.1_A3.2_T1
+author: Sam Mikes
+description: >
+    "rejected" handler invoked correctly outside of strict mode
+flags: [async, noStrict]
+---*/
+
+var expectedThis = this,
+  obj = {};
+
+var p = Promise.reject(obj).then(function() {
+  $DONE("Unexpected fulfillment; expected rejection.");
+}, function(arg) {
+  if (this !== expectedThis) {
+    $DONE("'this' must be global object, got " + this);
+    return;
+  }
+
+  if (arg !== obj) {
+    $DONE("Expected promise to be rejected with obj, actually " + arg);
+    return;
+  }
+
+  if (arguments.length !== 1) {
+    $DONE('Expected handler function to be called with exactly 1 argument.');
+    return;
+  }
+
+  $DONE();
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-invoke-strict-strict.js b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-invoke-strict-strict.js
new file mode 100644
index 0000000000..09f0954c0d
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-invoke-strict-strict.js
@@ -0,0 +1,39 @@
+// |reftest| async
+'use strict';
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    [...]
+    6. Else, let handlerResult be Call(handler, undefined, «argument»).
+es6id: S25.4.2.1_A3.2_T2
+author: Sam Mikes
+description: >
+    "rejected" handler invoked correctly in strict mode
+flags: [async, onlyStrict]
+---*/
+
+var expectedThis = undefined,
+  obj = {};
+
+var p = Promise.reject(obj).then(function() {
+  $DONE("Unexpected fulfillment; expected rejection.");
+}, function(arg) {
+  if (this !== expectedThis) {
+    $DONE("'this' must be undefined, got " + this);
+    return;
+  }
+
+  if (arg !== obj) {
+    $DONE("Expected promise to be rejected with obj, actually " + arg);
+    return;
+  }
+
+  if (arguments.length !== 1) {
+    $DONE('Expected handler function to be called with exactly 1 argument.');
+    return;
+  }
+
+  $DONE();
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-next-abrupt.js b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-next-abrupt.js
new file mode 100644
index 0000000000..681f4fabc1
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-next-abrupt.js
@@ -0,0 +1,46 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Abrupt completions should not preclude additional jobs
+es6id: 25.4.2.1
+info: |
+    [...]
+    7. If handlerResult is an abrupt completion, then
+       a. Let status be Call(promiseCapability.[[Reject]], undefined,
+          «handlerResult.[[value]]»).
+       b. NextJob Completion(status).
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    9. NextJob Completion(status).
+flags: [async]
+---*/
+
+var promise = new Promise(function(_, reject) {
+  reject();
+});
+var fulfilledCallCount = 0;
+var rejectedCallCount = 0;
+
+promise.then(function() {
+  fulfilledCallCount += 1;
+}, function() {
+  rejectedCallCount += 1;
+  throw new Error();
+});
+
+promise.then(function() {
+  $DONE('This promise should not be fulfilled.');
+}, function() {
+  if (fulfilledCallCount !== 0) {
+    $DONE('Expected "onFulfilled" handler to not be invoked.');
+    return;
+  }
+
+  if (rejectedCallCount !== 1) {
+    $DONE('Expected "onRejected" handler to be invoked exactly once.');
+    return;
+  }
+
+  $DONE();
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-next.js b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-next.js
new file mode 100644
index 0000000000..d88d3e1a48
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-next.js
@@ -0,0 +1,54 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: All queued jobs should be executed in series
+es6id: 25.4.2.1
+info: |
+    [...]
+    7. If handlerResult is an abrupt completion, then
+       a. Let status be Call(promiseCapability.[[Reject]], undefined,
+          «handlerResult.[[value]]»).
+       b. NextJob Completion(status).
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    9. NextJob Completion(status).
+flags: [async]
+---*/
+
+var promise = new Promise(function(_, reject) {
+  reject();
+});
+var log = '';
+
+promise.then(function() {
+  log += 'A';
+}, function() {
+  log += 'a';
+});
+
+promise.then(function() {
+  log += 'B';
+}, function() {
+  log += 'b';
+});
+
+promise.then(function() {
+  log += 'C';
+}, function() {
+  log += 'c';
+});
+
+promise.then(function() {
+  $DONE('This promise should not be fulfilled.');
+}, function() {
+  if (log !== 'abc') {
+    $DONE(
+      'Expected each "onFulfilled" handler to be invoked exactly once in series. ' +
+      'Expected: abc. Actual: ' + log
+    );
+    return;
+  }
+
+  $DONE();
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-return-abrupt.js b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-return-abrupt.js
new file mode 100644
index 0000000000..8b89456853
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-return-abrupt.js
@@ -0,0 +1,51 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: An abrupt completion should trigger promise rejection
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    9. Else if the value of promise's [[PromiseState]] internal slot is
+       "rejected",
+       a. Let reason be the value of promise's [[PromiseResult]] internal slot.
+       b. Perform EnqueueJob("PromiseJobs", PromiseReactionJob,
+          «rejectReaction, reason»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    7. If handlerResult is an abrupt completion, then
+       a. Let status be Call(promiseCapability.[[Reject]], undefined,
+          «handlerResult.[[value]]»).
+       b. NextJob Completion(status).
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    9. NextJob Completion(status).
+flags: [async]
+---*/
+
+var value = {};
+var p1 = new Promise(function(_, reject) {
+  reject();
+});
+var p2;
+
+p2 = p1.then(function() {}, function() {
+  throw value;
+});
+
+p2.then(function() {
+  $DONE('The `onFulfilled` handler should not be invoked.');
+}, function(x) {
+  if (x !== value) {
+    $DONE('The `onRejected` handler should be invoked with the promise result.');
+    return;
+  }
+
+  $DONE();
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-return-normal.js b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-return-normal.js
new file mode 100644
index 0000000000..d29489baa8
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-rejected-return-normal.js
@@ -0,0 +1,51 @@
+// |reftest| async
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: A normal completion should trigger promise fulfillment
+es6id: 25.4.5.3
+info: |
+    [...]
+    7. Return PerformPromiseThen(promise, onFulfilled, onRejected,
+       resultCapability).
+
+    25.4.5.3.1 PerformPromiseThen
+    [...]
+    9. Else if the value of promise's [[PromiseState]] internal slot is
+       "rejected",
+       a. Let reason be the value of promise's [[PromiseResult]] internal slot.
+       b. Perform EnqueueJob("PromiseJobs", PromiseReactionJob,
+          «rejectReaction, reason»).
+
+    25.4.2.1 PromiseReactionJob
+    [...]
+    7. If handlerResult is an abrupt completion, then
+       a. Let status be Call(promiseCapability.[[Reject]], undefined,
+          «handlerResult.[[value]]»).
+       b. NextJob Completion(status).
+    8. Let status be Call(promiseCapability.[[Resolve]], undefined,
+       «handlerResult.[[value]]»).
+    9. NextJob Completion(status).
+flags: [async]
+---*/
+
+var value = {};
+var p1 = new Promise(function(_, reject) {
+  reject();
+});
+var p2;
+
+p2 = p1.then(function() {}, function() {
+  return value;
+});
+
+p2.then(function(x) {
+  if (x !== value) {
+    $DONE('The `onFulfilled` handler should be invoked with the promise result.');
+    return;
+  }
+
+  $DONE();
+}, function() {
+  $DONE('The `onRejected` handler should not be invoked.');
+});
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-thrower.js b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-thrower.js
new file mode 100644
index 0000000000..6961da914e
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/rxn-handler-thrower.js
@@ -0,0 +1,25 @@
+// |reftest| async
+// Copyright 2014 Cubane Canada, Inc.  All rights reserved.
+// See LICENSE for details.
+
+/*---
+info: |
+    Promise reaction jobs have predictable environment
+es6id: S25.4.2.1_A2.1_T1
+author: Sam Mikes
+description: argument thrown through "Thrower"
+flags: [async]
+---*/
+
+var obj = {};
+
+var p = Promise.reject(obj).then( /*Identity, Thrower*/ )
+  .then(function() {
+    $DONE("Unexpected fulfillment - promise should reject.");
+  }, function(arg) {
+    if (arg !== obj) {
+      $DONE("Expected reject reason to be obj, actually " + arg);
+      return;
+    }
+    $DONE();
+  });
diff --git a/js/src/tests/test262/built-ins/Promise/prototype/then/shell.js b/js/src/tests/test262/built-ins/Promise/prototype/then/shell.js
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Promise/prototype/then/shell.js