Add tests for AggregateError (#2406)

This covers part of the Promise.any proposal

features.txt

@@ -153,6 +153,11 @@ coalesce-expression
 # https://github.com/tc39-transfer/proposal-intl-displaynames
 Intl.DisplayNames
 
+# Promise.any
+# https://github.com/tc39/proposal-promise-any
+Promise.any
+AggregateError
+
 ## Standard language features
 #
 # Language features that have been included in a published version of the

test/built-ins/AggregateError/errors-iterabletolist-failures.js

@@ -0,0 +1,183 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error
+description: >
+  Return abrupt completion from IterableToList(errors)
+info: |
+  AggregateError ( errors, message )
+
+  ...
+  3. Let errorsList be ? IterableToList(errors).
+  4. Set O.[[AggregateErrors]] to errorsList.
+  ...
+  6. Return O.
+
+  Runtime Semantics: IterableToList ( items [ , method ] )
+
+  1. If method is present, then
+    ...
+  2. Else,
+    b. Let iteratorRecord be ? GetIterator(items, sync).
+  3. Let values be a new empty List.
+  4. Let next be true.
+  5. Repeat, while next is not false
+    a. Set next to ? IteratorStep(iteratorRecord).
+    b. If next is not false, then
+      i. Let nextValue be ? IteratorValue(next).
+      ii. Append nextValue to the end of the List values.
+  6. Return values.
+
+  GetIterator ( obj [ , hint [ , method ] ] )
+
+  ...
+  3. If method is not present, then
+    a. If hint is async, then
+      ...
+    b. Otherwise, set method to ? GetMethod(obj, @@iterator).
+  4. Let iterator be ? Call(method, obj).
+  5. If Type(iterator) is not Object, throw a TypeError exception.
+  6. Let nextMethod be ? GetV(iterator, "next").
+  ...
+  8. Return iteratorRecord.
+features: [AggregateError, Symbol.iterator]
+---*/
+
+var case1 = {
+  get [Symbol.iterator]() {
+    throw new Test262Error();
+  }
+};
+
+assert.throws(Test262Error, () => {
+  var obj = new AggregateError(case1);
+}, 'get Symbol.iterator');
+
+var case2 = {
+  get [Symbol.iterator]() {
+    return {};
+  }
+};
+
+assert.throws(TypeError, () => {
+  var obj = new AggregateError(case2);
+}, 'GetMethod(obj, @@iterator) abrupts from non callable');
+
+var case3 = {
+  [Symbol.iterator]() {
+    throw new Test262Error();
+  }
+};
+
+assert.throws(Test262Error, () => {
+  var obj = new AggregateError(case3);
+}, 'Abrupt from @@iterator call');
+
+var case4 = {
+  [Symbol.iterator]() {
+    return 'a string';
+  }
+};
+
+assert.throws(TypeError, () => {
+  var obj = new AggregateError(case4);
+}, '@@iterator call returns a string');
+
+var case5 = {
+  [Symbol.iterator]() {
+    return undefined;
+  }
+};
+
+assert.throws(TypeError, () => {
+  var obj = new AggregateError(case5);
+}, '@@iterator call returns undefined');
+
+var case6 = {
+  [Symbol.iterator]() {
+    return {
+      get next() {
+        throw new Test262Error();
+      }
+    }
+  }
+};
+
+assert.throws(Test262Error, () => {
+  var obj = new AggregateError(case6);
+}, 'GetV(iterator, next) returns abrupt');
+
+var case7 = {
+  [Symbol.iterator]() {
+    return {
+      get next() {
+        return {};
+      }
+    }
+  }
+};
+
+assert.throws(TypeError, () => {
+  var obj = new AggregateError(case7);
+}, 'GetV(iterator, next) returns a non callable');
+
+var case8 = {
+  [Symbol.iterator]() {
+    return {
+      next() {
+        throw new Test262Error();
+      }
+    }
+  }
+};
+
+assert.throws(Test262Error, () => {
+  var obj = new AggregateError(case8);
+}, 'abrupt from iterator.next()');
+
+var case9 = {
+  [Symbol.iterator]() {
+    return {
+      next() {
+        return undefined;
+      }
+    }
+  }
+};
+
+assert.throws(TypeError, () => {
+  var obj = new AggregateError(case9);
+}, 'iterator.next() returns undefined');
+
+var case10 = {
+  [Symbol.iterator]() {
+    return {
+      next() {
+        return 'a string';
+      }
+    }
+  }
+};
+
+assert.throws(TypeError, () => {
+  var obj = new AggregateError(case10);
+}, 'iterator.next() returns a string');
+
+var case11 = {
+  [Symbol.iterator]() {
+    return {
+      next() {
+        return {
+          get done() {
+            throw new Test262Error();
+          }
+        };
+      }
+    }
+  }
+};
+
+assert.throws(Test262Error, () => {
+  var obj = new AggregateError(case11);
+}, 'IteratorCompete abrupts getting the done property');

test/built-ins/AggregateError/errors-iterabletolist.js

@@ -0,0 +1,69 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error
+description: >
+  Iteration of errors
+info: |
+  AggregateError ( errors, message )
+
+  ...
+  3. Let errorsList be ? IterableToList(errors).
+  4. Set O.[[AggregateErrors]] to errorsList.
+  ...
+  6. Return O.
+
+  Runtime Semantics: IterableToList ( items [ , method ] )
+
+  1. If method is present, then
+    ...
+  2. Else,
+    b. Let iteratorRecord be ? GetIterator(items, sync).
+  3. Let values be a new empty List.
+  4. Let next be true.
+  5. Repeat, while next is not false
+    a. Set next to ? IteratorStep(iteratorRecord).
+    b. If next is not false, then
+      i. Let nextValue be ? IteratorValue(next).
+      ii. Append nextValue to the end of the List values.
+  6. Return values.
+
+  GetIterator ( obj [ , hint [ , method ] ] )
+
+  ...
+  3. If method is not present, then
+    a. If hint is async, then
+      ...
+    b. Otherwise, set method to ? GetMethod(obj, @@iterator).
+  4. Let iterator be ? Call(method, obj).
+  5. If Type(iterator) is not Object, throw a TypeError exception.
+  6. Let nextMethod be ? GetV(iterator, "next").
+  ...
+  8. Return iteratorRecord.
+features: [AggregateError, Symbol.iterator]
+includes: [compareArray.js]
+---*/
+
+var count = 0;
+var values = [];
+var case1 = {
+  [Symbol.iterator]() {
+    return {
+      next() {
+        count += 1;
+        return {
+          done: count === 3,
+          get value() {
+            values.push(count)
+          }
+        };
+      }
+    };
+  }
+};
+
+new AggregateError(case1);
+
+assert.sameValue(count, 3);
+assert.compareArray(values, [1, 2]);

test/built-ins/AggregateError/length.js

@@ -0,0 +1,32 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error
+description: AggregateError.length property descriptor
+info: |
+  AggregateError ( errors, message )
+
+  17 ECMAScript Standard Built-in Objects
+
+  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. Optional parameters
+  (which are indicated with brackets: [ ]) or rest parameters (which
+  are shown using the form «...name») are not included in the default
+  argument count.
+
+  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: [AggregateError]
+---*/
+
+verifyProperty(AggregateError, 'length', {
+  value: 2,
+  writable: false,
+  enumerable: false,
+  configurable: true
+});

test/built-ins/AggregateError/message-method-prop-cast.js

@@ -0,0 +1,69 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error
+description: >
+  Cast ToString values of message in the created method property
+info: |
+  AggregateError ( errors, message )
+
+  ...
+  5. If message is not undefined, then
+    a. Let msg be ? ToString(message).
+    b. Perform ! CreateMethodProperty(O, "message", msg).
+  6. Return O.
+
+  CreateMethodProperty ( O, P, V )
+
+  ...
+  3. Let newDesc be the PropertyDescriptor { [[Value]]: V, [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true }.
+  4. Return ? O.[[DefineOwnProperty]](P, newDesc).
+features: [AggregateError]
+includes: [propertyHelper.js]
+---*/
+
+var case1 = new AggregateError([], 42);
+
+verifyProperty(case1, 'message', {
+  value: '42',
+  writable: true,
+  enumerable: false,
+  configurable: true,
+});
+
+var case2 = new AggregateError([], false);
+
+verifyProperty(case2, 'message', {
+  value: 'false',
+  writable: true,
+  enumerable: false,
+  configurable: true,
+});
+
+var case3 = new AggregateError([], true);
+
+verifyProperty(case3, 'message', {
+  value: 'true',
+  writable: true,
+  enumerable: false,
+  configurable: true,
+});
+
+var case4 = new AggregateError([], { toString() { return 'string'; }});
+
+verifyProperty(case4, 'message', {
+  value: 'string',
+  writable: true,
+  enumerable: false,
+  configurable: true,
+});
+
+var case5 = new AggregateError([], null);
+
+verifyProperty(case5, 'message', {
+  value: 'null',
+  writable: true,
+  enumerable: false,
+  configurable: true,
+});

test/built-ins/AggregateError/message-method-prop.js

@@ -0,0 +1,33 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error
+description: >
+  Creates a method property for message
+info: |
+  AggregateError ( errors, message )
+
+  ...
+  5. If message is not undefined, then
+    a. Let msg be ? ToString(message).
+    b. Perform ! CreateMethodProperty(O, "message", msg).
+  6. Return O.
+
+  CreateMethodProperty ( O, P, V )
+
+  ...
+  3. Let newDesc be the PropertyDescriptor { [[Value]]: V, [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: true }.
+  4. Return ? O.[[DefineOwnProperty]](P, newDesc).
+features: [AggregateError]
+includes: [propertyHelper.js]
+---*/
+
+var obj = new AggregateError([], '42');
+
+verifyProperty(obj, 'message', {
+  value: '42',
+  writable: true,
+  enumerable: false,
+  configurable: true,
+});

test/built-ins/AggregateError/message-tostring-abrupt-symbol.js

@@ -0,0 +1,39 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error
+description: >
+  Abrupt completions of ToString(Symbol message)
+info: |
+  AggregateError ( errors, message )
+
+  ...
+  5. If message is not undefined, then
+    a. Let msg be ? ToString(message).
+    b. Perform ! CreateMethodProperty(O, "message", msg).
+  6. Return O.
+features: [AggregateError, Symbol, Symbol.toPrimitive]
+---*/
+
+var case1 = Symbol();
+
+assert.throws(TypeError, () => {
+  new AggregateError([], case1);
+}, 'toPrimitive');
+
+var case2 = {
+  [Symbol.toPrimitive]() {
+    return Symbol();
+  },
+  toString() {
+    throw new Test262Error();
+  },
+  valueOf() {
+    throw new Test262Error();
+  }
+};
+
+assert.throws(TypeError, () => {
+  new AggregateError([], case2);
+}, 'from ToPrimitive');

test/built-ins/AggregateError/message-tostring-abrupt.js

@@ -0,0 +1,59 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error
+description: >
+  Abrupt completions of ToString(message)
+info: |
+  AggregateError ( errors, message )
+
+  ...
+  5. If message is not undefined, then
+    a. Let msg be ? ToString(message).
+    b. Perform ! CreateMethodProperty(O, "message", msg).
+  6. Return O.
+features: [AggregateError, Symbol.toPrimitive]
+---*/
+
+var case1 = {
+  [Symbol.toPrimitive]() {
+    throw new Test262Error();
+  },
+  toString() {
+    throw 'toString called';
+  },
+  valueOf() {
+    throw 'valueOf called';
+  }
+};
+
+assert.throws(Test262Error, () => {
+  new AggregateError([], case1);
+}, 'toPrimitive');
+
+var case2 = {
+  [Symbol.toPrimitive]: undefined,
+  toString() {
+    throw new Test262Error();
+  },
+  valueOf() {
+    throw 'valueOf called';
+  }
+};
+
+assert.throws(Test262Error, () => {
+  new AggregateError([], case2);
+}, 'toString');
+
+var case3 = {
+  [Symbol.toPrimitive]: undefined,
+  toString: undefined,
+  valueOf() {
+    throw new Test262Error();
+  }
+};
+
+assert.throws(Test262Error, () => {
+  new AggregateError([], case3);
+}, 'valueOf');

test/built-ins/AggregateError/message-undefined-no-prop.js

@@ -0,0 +1,33 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error
+description: >
+  If message is undefined, no property will be set to the new instance
+info: |
+  AggregateError ( errors, message )
+
+  ...
+  5. If message is not undefined, then
+    a. Let msg be ? ToString(message).
+    b. Perform ! CreateMethodProperty(O, "message", msg).
+  6. Return O.
+features: [AggregateError]
+---*/
+
+var case1 = new AggregateError([], undefined);
+
+assert.sameValue(
+  Object.prototype.hasOwnProperty.call(case1, 'message'),
+  false,
+  'explicit'
+);
+
+var case2 = new AggregateError([]);
+
+assert.sameValue(
+  Object.prototype.hasOwnProperty.call(case2, 'message'),
+  false,
+  'implicit'
+);

test/built-ins/AggregateError/name.js

@@ -0,0 +1,33 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error
+description: AggregateError.name property descriptor
+info: |
+  Properties of the AggregateError Constructor
+
+  - has a name property whose value is the String value "AggregateError".
+
+  17 ECMAScript Standard Built-in Objects
+
+  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. For functions that
+  are specified as properties of objects, the name value is the
+  property name string used to access the function. [...]
+
+  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: [AggregateError]
+---*/
+
+verifyProperty(AggregateError, 'name', {
+  value: 'AggregateError',
+  writable: false,
+  enumerable: false,
+  configurable: true
+});

test/built-ins/AggregateError/newtarget-proto-custom.js

@@ -0,0 +1,47 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error
+description: >
+  Use a custom NewTarget prototype
+info: |
+  AggregateError ( errors, message )
+
+  1. If NewTarget is undefined, let newTarget be the active function object, else let newTarget be NewTarget.
+  2. Let O be ? OrdinaryCreateFromConstructor(newTarget, "%AggregateError.prototype%", « [[ErrorData]], [[AggregateErrors]] »).
+  ...
+  6. Return O.
+
+  OrdinaryCreateFromConstructor ( constructor, intrinsicDefaultProto [ , internalSlotsList ] )
+
+  ...
+  2. Let proto be ? GetPrototypeFromConstructor(constructor, intrinsicDefaultProto).
+  3. Return ObjectCreate(proto, internalSlotsList).
+
+  GetPrototypeFromConstructor ( constructor, intrinsicDefaultProto )
+
+  ...
+  3. Let proto be ? Get(constructor, "prototype").
+  4. If Type(proto) is not Object, then
+    a. Let realm be ? GetFunctionRealm(constructor).
+    b. Set proto to realm's intrinsic object named intrinsicDefaultProto.
+  Return proto.
+features: [AggregateError]
+---*/
+
+var custom = { x: 42 };
+var newt = new Proxy(function() {}, {
+  get(t, p) {
+    if (p === 'prototype') {
+      return custom;
+    }
+
+    return t[p];
+  }
+});
+
+var obj = Reflect.construct(AggregateError, [], newt);
+
+assert.sameValue(Object.getPrototypeOf(obj), custom);
+assert.sameValue(obj.x, 42);

test/built-ins/AggregateError/newtarget-proto-fallback.js

@@ -0,0 +1,62 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error
+description: >
+  Fallback to the NewTarget's [[Prototype]] if the prototype property is not an object
+info: |
+  AggregateError ( errors, message )
+
+  1. If NewTarget is undefined, let newTarget be the active function object, else let newTarget be NewTarget.
+  2. Let O be ? OrdinaryCreateFromConstructor(newTarget, "%AggregateError.prototype%", « [[ErrorData]], [[AggregateErrors]] »).
+  ...
+  6. Return O.
+
+  OrdinaryCreateFromConstructor ( constructor, intrinsicDefaultProto [ , internalSlotsList ] )
+
+  ...
+  2. Let proto be ? GetPrototypeFromConstructor(constructor, intrinsicDefaultProto).
+  3. Return ObjectCreate(proto, internalSlotsList).
+
+  GetPrototypeFromConstructor ( constructor, intrinsicDefaultProto )
+
+  ...
+  3. Let proto be ? Get(constructor, "prototype").
+  4. If Type(proto) is not Object, then
+    a. Let realm be ? GetFunctionRealm(constructor).
+    b. Set proto to realm's intrinsic object named intrinsicDefaultProto.
+  Return proto.
+features: [AggregateError, Symbol]
+---*/
+
+var custom = { x: 42 };
+var ctor = function() {};
+Object.setPrototypeOf(ctor, custom);
+
+var values = [
+  undefined,
+  null,
+  42,
+  false,
+  true,
+  Symbol(),
+  'string'
+];
+
+for (const value of values) {
+  const newt = new Proxy(ctor, {
+    get(t, p) {
+      if (p === 'prototype') {
+        return value;
+      }
+
+      return t[p];
+    }
+  });
+
+  const obj = Reflect.construct(AggregateError, [], newt);
+
+  assert.sameValue(Object.getPrototypeOf(obj), custom);
+  assert.sameValue(obj.x, 42);
+}

test/built-ins/AggregateError/newtarget-proto.js

@@ -0,0 +1,35 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error
+description: >
+  Default prototype is the %AggregateError.prototype%"
+info: |
+  AggregateError ( errors, message )
+
+  1. If NewTarget is undefined, let newTarget be the active function object, else let newTarget be NewTarget.
+  2. Let O be ? OrdinaryCreateFromConstructor(newTarget, "%AggregateError.prototype%", « [[ErrorData]], [[AggregateErrors]] »).
+  ...
+  6. Return O.
+
+  OrdinaryCreateFromConstructor ( constructor, intrinsicDefaultProto [ , internalSlotsList ] )
+
+  ...
+  2. Let proto be ? GetPrototypeFromConstructor(constructor, intrinsicDefaultProto).
+  3. Return ObjectCreate(proto, internalSlotsList).
+
+  GetPrototypeFromConstructor ( constructor, intrinsicDefaultProto )
+
+  ...
+  3. Let proto be ? Get(constructor, "prototype").
+  4. If Type(proto) is not Object, then
+    a. Let realm be ? GetFunctionRealm(constructor).
+    b. Set proto to realm's intrinsic object named intrinsicDefaultProto.
+  Return proto.
+features: [AggregateError]
+---*/
+
+var obj = new AggregateError([]);
+
+assert.sameValue(Object.getPrototypeOf(obj), AggregateError.prototype);

test/built-ins/AggregateError/prop-desc.js

@@ -0,0 +1,26 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error
+description: >
+  Property descriptor of AggregateError
+info: |
+  The AggregateError Object
+
+  ECMAScript Standard Built-in Objects:
+
+  Every other data property described in clauses 18 through 26 and in Annex B.2
+  has the attributes { [[Writable]]: true, [[Enumerable]]: false,
+  [[Configurable]]: true } unless otherwise specified.
+includes: [propertyHelper.js]
+features: [AggregateError]
+---*/
+
+assert.sameValue(typeof AggregateError, 'function');
+
+verifyProperty(this, 'AggregateError', {
+  enumerable: false,
+  writable: true,
+  configurable: true
+});

test/built-ins/AggregateError/proto.js

@@ -0,0 +1,16 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: The prototype of AggregateError constructor is Error
+esid: sec-aggregate-error
+info: |
+  Properties of the AggregateError Constructor
+
+  - has a [[Prototype]] internal slot whose value is the intrinsic object %Error%.
+features: [AggregateError]
+---*/
+
+var proto = Object.getPrototypeOf(AggregateError);
+
+assert.sameValue(proto, Error);

test/built-ins/AggregateError/prototype/constructor.js

@@ -0,0 +1,25 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.constructor
+description: >
+  The `AggregateError.prototype.constructor` property descriptor.
+info: |
+  The initial value of AggregateError.prototype.constructor is the intrinsic
+  object %AggregateError%.
+
+  17 ECMAScript Standard Built-in Objects:
+
+  Every other data property described (...) has the attributes { [[Writable]]: true,
+    [[Enumerable]]: false, [[Configurable]]: true } unless otherwise specified.
+includes: [propertyHelper.js]
+features: [AggregateError]
+---*/
+
+verifyProperty(AggregateError.prototype, 'constructor', {
+  value: AggregateError,
+  enumerable: false,
+  writable: true,
+  configurable: true
+});

test/built-ins/AggregateError/prototype/errors/invoked-as-accessor.js

@@ -0,0 +1,21 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-get-aggregate-error.prototype.errors
+description: >
+  Requires this value to have a [[AggregateErrorData]] internal slot
+info: |
+  get AggregateError.prototype.errors
+
+  1. Let E be the this value.
+  2. If Type(E) is not Object, throw a TypeError exception.
+  3. If E does not have an [[ErrorData]] internal slot, throw a TypeError exception.
+  4. If E does not have an [[AggregateErrors]] internal slot, throw a TypeError exception.
+  5. Return ! CreateArrayFromList(E.[[AggregateErrors]]).
+features: [AggregateError]
+---*/
+
+assert.throws(TypeError, function() {
+  AggregateError.prototype.errors;
+});

test/built-ins/AggregateError/prototype/errors/invoked-as-func.js

@@ -0,0 +1,25 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-get-aggregate-error.prototype.errors
+description: >
+  Throws a TypeError exception when invoked as a function
+info: |
+  get AggregateError.prototype.errors
+
+  1. Let E be the this value.
+  2. If Type(E) is not Object, throw a TypeError exception.
+  3. If E does not have an [[ErrorData]] internal slot, throw a TypeError exception.
+  4. If E does not have an [[AggregateErrors]] internal slot, throw a TypeError exception.
+  5. Return ! CreateArrayFromList(E.[[AggregateErrors]]).
+features: [AggregateError]
+---*/
+
+var getter = Object.getOwnPropertyDescriptor(
+  AggregateError.prototype, 'errors'
+).get;
+
+assert.throws(TypeError, function() {
+  getter();
+});

test/built-ins/AggregateError/prototype/errors/length.js

@@ -0,0 +1,33 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-get-aggregate-error.prototype.errors
+description: >
+  Property descriptor of (get AggregateError.prototype.errors).length
+info: |
+  get AggregateError.prototype.errors
+
+  17 ECMAScript Standard Built-in Objects:
+    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. However, rest parameters shown using the form “...name”
+    are not included in the default argument count.
+
+    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: [AggregateError]
+---*/
+
+var desc = Object.getOwnPropertyDescriptor(AggregateError.prototype, 'errors');
+
+verifyProperty(desc.get, 'length', {
+  value: 0,
+  enumerable: false,
+  writable: false,
+  configurable: true
+});

test/built-ins/AggregateError/prototype/errors/name.js

@@ -0,0 +1,28 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-get-aggregate-error.prototype.errors
+description: >
+  Property descriptor of (get AggregateError.prototype.errors).name
+info: |
+  get AggregateError.prototype.errors
+
+  17 ECMAScript Standard Built-in Objects
+
+  Functions that are specified as get or set accessor functions of built-in
+  properties have "get " or "set " prepended to the property name string.
+includes: [propertyHelper.js]
+features: [AggregateError]
+---*/
+
+var desc = Object.getOwnPropertyDescriptor(
+  AggregateError.prototype, 'errors'
+);
+
+verifyProperty(desc.get, 'name', {
+  value: 'get errors',
+  enumerable: false,
+  writable: false,
+  configurable: true
+});

test/built-ins/AggregateError/prototype/errors/prop-desc.js

@@ -0,0 +1,25 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-get-aggregate-error.prototype.errors
+description: >
+  "errors" property of AggregateError.prototype
+info: |
+  AggregateError.prototype.errors is an accessor property whose set accessor
+  function is undefined.
+
+  Section 17: Every accessor property described in clauses 18 through 26 and in
+  Annex B.2 has the attributes {[[Enumerable]]: false, [[Configurable]]: true }
+includes: [propertyHelper.js]
+features: [AggregateError]
+---*/
+
+var desc = Object.getOwnPropertyDescriptor(AggregateError.prototype, 'errors');
+
+assert.sameValue(desc.set, undefined);
+assert.sameValue(typeof desc.get, 'function');
+
+verifyProperty(AggregateError.prototype, 'errors', {
+  enumerable: false,
+  configurable: true
+});

test/built-ins/AggregateError/prototype/errors/return-from-iterable-errors.js

@@ -0,0 +1,51 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-get-aggregate-error.prototype.errors
+description: >
+  Return a new array from the [[AggregateErrors]] list, after an iterable errors arg.
+info: |
+  get AggregateError.prototype.errors
+
+  1. Let E be the this value.
+  ...
+  5. Return ! CreateArrayFromList(E.[[AggregateErrors]]).
+includes: [compareArray.js]
+features: [AggregateError, Symbol.iterator]
+---*/
+
+var count = 0;
+var errors = {
+  [Symbol.iterator]() {
+    return {
+      next() {
+        count += 1;
+        return {
+          done: count === 3,
+          get value() {
+            return count * 3;
+          }
+        };
+      }
+    };
+  }
+};
+
+var case1 = new AggregateError(errors);
+
+assert.sameValue(count, 3);
+
+var get1 = case1.errors;
+var get2 = case1.errors;
+
+assert.sameValue(Array.isArray(get1), true);
+assert.sameValue(Array.isArray(get2), true);
+
+assert.notSameValue(get1, errors, 'creates a new array #1');
+assert.notSameValue(get2, errors, 'creates a new array #2');
+assert.notSameValue(get1, get2, 'creates a new array everytime it gets the values');
+
+assert.compareArray(get1, [3, 6], 'get accessor does not trigger a new iteration #1');
+assert.compareArray(get2, [3, 6], 'get accessor does not trigger a new iteration #2');
+
+assert.sameValue(count, 3, 'count is preserved');

test/built-ins/AggregateError/prototype/errors/return-new-array-from-list.js

@@ -0,0 +1,76 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-get-aggregate-error.prototype.errors
+description: >
+  Return a new array from the [[AggregateErrors]] list.
+info: |
+  get AggregateError.prototype.errors
+
+  1. Let E be the this value.
+  ...
+  5. Return ! CreateArrayFromList(E.[[AggregateErrors]]).
+includes: [compareArray.js]
+features: [AggregateError, Symbol]
+---*/
+
+var errors = [];
+var case1 = new AggregateError(errors);
+var case1get1 = case1.errors;
+var case1get2 = case1.errors;
+
+assert.sameValue(Array.isArray(case1get1), true);
+assert.sameValue(Array.isArray(case1get2), true);
+
+assert.notSameValue(case1get1, errors, 'case1 - creates a new array #1');
+assert.notSameValue(case1get2, errors, 'case1 - creates a new array #2');
+assert.notSameValue(case1get1, case1get2, 'creates a new array everytime it gets the values');
+
+assert.compareArray(case1get1, errors);
+assert.compareArray(case1get2, errors);
+
+/////
+
+errors = [undefined, null, 1, 0, '', {}, Symbol()];
+var case2 = new AggregateError(errors);
+var case2get1 = case2.errors;
+var case2get2 = case2.errors;
+
+assert.sameValue(Array.isArray(case2get1), true);
+assert.sameValue(Array.isArray(case2get2), true);
+
+assert.notSameValue(case2get1, errors, 'case2 - creates a new array #1');
+assert.notSameValue(case2get2, errors, 'case2 - creates a new array #2');
+assert.notSameValue(case2get1, case2get2, 'creates a new array everytime it gets the values');
+
+assert.compareArray(case2get1, errors);
+assert.compareArray(case2get2, errors);
+
+/////
+
+errors = [undefined,,,,undefined];
+var case3 = new AggregateError(errors);
+var case3get1 = case3.errors;
+var case3get2 = case3.errors;
+
+assert.sameValue(Array.isArray(case3get1), true);
+assert.sameValue(Array.isArray(case3get2), true);
+
+assert.notSameValue(case3get1, errors, 'case3 - creates a new array #1');
+assert.notSameValue(case3get2, errors, 'case3 - creates a new array #2');
+assert.notSameValue(case3get1, case3get2, 'creates a new array everytime it gets the values');
+
+assert.compareArray(case3get1, errors);
+assert.compareArray(case3get2, errors);
+
+assert(Object.prototype.hasOwnProperty.call(case3get1, 0), 'filled array from a sparse origin - case3get1, 0');
+assert(Object.prototype.hasOwnProperty.call(case3get1, 1), 'filled array from a sparse origin - case3get1, 1');
+assert(Object.prototype.hasOwnProperty.call(case3get1, 2), 'filled array from a sparse origin - case3get1, 2');
+assert(Object.prototype.hasOwnProperty.call(case3get1, 3), 'filled array from a sparse origin - case3get1, 3');
+assert(Object.prototype.hasOwnProperty.call(case3get1, 4), 'filled array from a sparse origin - case3get1, 4');
+
+assert(Object.prototype.hasOwnProperty.call(case3get2, 0), 'filled array from a sparse origin - case3get2, 0');
+assert(Object.prototype.hasOwnProperty.call(case3get2, 1), 'filled array from a sparse origin - case3get2, 1');
+assert(Object.prototype.hasOwnProperty.call(case3get2, 2), 'filled array from a sparse origin - case3get2, 2');
+assert(Object.prototype.hasOwnProperty.call(case3get2, 3), 'filled array from a sparse origin - case3get2, 3');
+assert(Object.prototype.hasOwnProperty.call(case3get2, 4), 'filled array from a sparse origin - case3get2, 4');

test/built-ins/AggregateError/prototype/errors/this-has-no-typedarrayname-internal.js

@@ -0,0 +1,29 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-get-aggregate-error.prototype.errors
+description: >
+  Throws a TypeError exception when `this` does not have a [[AggregateErrorData]]
+  internal slot
+info: |
+  get AggregateError.prototype.errors
+
+  1. Let E be the this value.
+  2. If Type(E) is not Object, throw a TypeError exception.
+  3. If E does not have an [[ErrorData]] internal slot, throw a TypeError exception.
+  4. If E does not have an [[AggregateErrors]] internal slot, throw a TypeError exception.
+  5. Return ! CreateArrayFromList(E.[[AggregateErrors]]).
+features: [AggregateError]
+---*/
+
+var getter = Object.getOwnPropertyDescriptor(
+  AggregateError.prototype, 'errors'
+).get;
+
+assert.throws(TypeError, function() {
+  getter.call(new Error());
+}, 'this is an instance of Error, no [[AggregateErrors]]');
+
+assert.throws(TypeError, function() {
+  getter.call(AggregateError);
+}, 'AggregateError does not have an [[AggregateErrors]] internal');

test/built-ins/AggregateError/prototype/errors/this-is-not-object.js

@@ -0,0 +1,46 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-get-aggregate-error.prototype.errors
+description: Throws a TypeError exception when `this` is not Object
+info: |
+  get AggregateError.prototype.errors
+
+  1. Let E be the this value.
+  2. If Type(E) is not Object, throw a TypeError exception.
+  ...
+features: [AggregateError, Symbol]
+---*/
+
+var getter = Object.getOwnPropertyDescriptor(
+  AggregateError.prototype, 'errors'
+).get;
+
+assert.throws(TypeError, function() {
+  getter.call(undefined);
+}, 'this is undefined');
+
+assert.throws(TypeError, function() {
+  getter.call(null);
+}, 'this is null');
+
+assert.throws(TypeError, function() {
+  getter.call(42);
+}, 'this is 42');
+
+assert.throws(TypeError, function() {
+  getter.call('1');
+}, 'this is a string');
+
+assert.throws(TypeError, function() {
+  getter.call(true);
+}, 'this is true');
+
+assert.throws(TypeError, function() {
+  getter.call(false);
+}, 'this is false');
+
+var s = Symbol('s');
+assert.throws(TypeError, function() {
+  getter.call(s);
+}, 'this is a Symbol');

test/built-ins/AggregateError/prototype/message.js

@@ -0,0 +1,25 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.message
+description: >
+  The `AggregateError.prototype.message` property descriptor.
+info: |
+  The initial value of the message property of the prototype for a given AggregateError
+  constructor is the empty String.
+
+  17 ECMAScript Standard Built-in Objects:
+
+  Every other data property described (...) has the attributes { [[Writable]]: true,
+    [[Enumerable]]: false, [[Configurable]]: true } unless otherwise specified.
+includes: [propertyHelper.js]
+features: [AggregateError]
+---*/
+
+verifyProperty(AggregateError.prototype, 'message', {
+  value: '',
+  enumerable: false,
+  writable: true,
+  configurable: true
+});

test/built-ins/AggregateError/prototype/name.js

@@ -0,0 +1,24 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.name
+description: >
+  The `AggregateError.prototype.name` property descriptor.
+info: |
+  The initial value of AggregateError.prototype.name is "AggregateError".
+
+  17 ECMAScript Standard Built-in Objects:
+
+  Every other data property described (...) has the attributes { [[Writable]]: true,
+    [[Enumerable]]: false, [[Configurable]]: true } unless otherwise specified.
+includes: [propertyHelper.js]
+features: [AggregateError]
+---*/
+
+verifyProperty(AggregateError.prototype, 'name', {
+  value: 'AggregateError',
+  enumerable: false,
+  writable: true,
+  configurable: true
+});

test/built-ins/AggregateError/prototype/prop-desc.js

@@ -0,0 +1,24 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype
+description: >
+  Property descriptor of AggregateError.prototype
+info: |
+  AggregateError.prototype
+
+  The initial value of AggregateError.prototype is the intrinsic object %AggregateErrorPrototype%.
+
+  This property has the attributes { [[Writable]]: false, [[Enumerable]]: false, [[Configurable]]: false }.
+includes: [propertyHelper.js]
+features: [AggregateError]
+---*/
+
+assert.sameValue(typeof AggregateError.prototype, 'object');
+
+verifyProperty(AggregateError, 'prototype', {
+  enumerable: false,
+  writable: false,
+  configurable: false
+});

test/built-ins/AggregateError/prototype/proto.js

@@ -0,0 +1,16 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-properties-of-the-aggregate-error-prototype-objects
+description: The prototype of AggregateError.prototype constructor is Error.prototype
+info: |
+  Properties of the AggregateError Prototype Object
+
+  - has a [[Prototype]] internal slot whose value is the intrinsic object %Error.prototype%.
+features: [AggregateError]
+---*/
+
+var proto = Object.getPrototypeOf(AggregateError.prototype);
+
+assert.sameValue(proto, Error.prototype);

test/built-ins/AggregateError/prototype/toString/get-message-abrupt.js

@@ -0,0 +1,39 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  Gets the Object message, returning abrupt completion
+info: |
+  AggregateError.prototype.toString ( )
+
+  ...
+  5. Let msg be ? Get(O, "message").
+  6. If msg is undefined, set msg to the empty String; otherwise set msg to ? ToString(msg).
+  7. If name is the empty String, return msg.
+  8. If msg is the empty String, return name.
+  9. Return the string-concatenation of name, the code unit 0x003A (COLON), the code unit 0x0020 (SPACE) and msg.
+features: [AggregateError]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var called = 0;
+var nameCalled = 0;
+var obj = {
+  get name() {
+    nameCalled += 1;
+  },
+  get message() {
+    called += 1;
+    throw new Test262Error();
+  }
+};
+
+assert.throws(Test262Error, () => {
+  method.call(obj);
+});
+
+assert.sameValue(called, 1);
+assert.sameValue(nameCalled, 1);

test/built-ins/AggregateError/prototype/toString/get-message-empty-string.js

@@ -0,0 +1,54 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  If message value is the empty string, return name
+info: |
+  AggregateError.prototype.toString ( )
+
+  1. Let O be the this value.
+  2. If Type(O) is not Object, throw a TypeError exception.
+  3. Let name be ? Get(O, "name").
+  4. If name is undefined, set name to "AggregateError"; otherwise set name to ? ToString(name).
+  5. Let msg be ? Get(O, "message").
+  6. If msg is undefined, set msg to the empty String; otherwise set msg to ? ToString(msg).
+  7. If name is the empty String, return msg.
+  8. If msg is the empty String, return name.
+  9. Return the string-concatenation of name, the code unit 0x003A (COLON), the code unit 0x0020 (SPACE) and msg.
+features: [AggregateError]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var result = method.call({
+  name: 'the name',
+  message: '',
+});
+
+assert.sameValue(result, 'the name', 'explicit from own property');
+
+result = false;
+result = method.call(Object.create({
+  name: 'the name',
+  message: '',
+}));
+
+assert.sameValue(result, 'the name', 'explicit from prototype');
+
+result = false;
+result = method.call({
+  name: 'the name',
+  message: undefined,
+});
+
+assert.sameValue(result, 'the name', 'message is undefined');
+
+result = false;
+result = method.call({
+  name: 'the name!',
+  message: { toString() { return ''; } },
+});
+
+assert.sameValue(result, 'the name!', 'return name');

test/built-ins/AggregateError/prototype/toString/get-message-toString-object.js

@@ -0,0 +1,83 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  ToString on the message object value
+info: |
+  AggregateError.prototype.toString ( )
+
+  1. Let O be the this value.
+  2. If Type(O) is not Object, throw a TypeError exception.
+  3. Let name be ? Get(O, "name").
+  4. If name is undefined, set name to "AggregateError"; otherwise set name to ? ToString(name).
+  5. Let msg be ? Get(O, "message").
+  6. If msg is undefined, set msg to the empty String; otherwise set msg to ? ToString(msg).
+  7. If name is the empty String, return msg.
+  8. If msg is the empty String, return name.
+  9. Return the string-concatenation of name, the code unit 0x003A (COLON), the code unit 0x0020 (SPACE) and msg.
+features: [AggregateError, Symbol.toPrimitive]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var called = 0;
+var obj = {
+  message: {
+    [Symbol.toPrimitive]() {
+      called += 1;
+      return 'from @@toPrimitive';
+    },
+    toString() {
+      throw new Test262Error();
+    },
+    valueOf() {
+      throw new Test262Error();
+    },
+  },
+  name: '',
+};
+
+var result = method.call(obj);
+
+assert.sameValue(called, 1);
+assert.sameValue(result, 'from @@toPrimitive');
+
+called = 0;
+obj = {
+  message: {
+    [Symbol.toPrimitive]: undefined,
+    toString() {
+      called += 1;
+      return 'from the toString method';
+    },
+    valueOf() {
+      throw new Test262Error();
+    },
+  },
+  name: '',
+};
+result = false;
+
+result = method.call(obj);
+assert.sameValue(called, 1);
+assert.sameValue(result, 'from the toString method');
+
+called = 0;
+obj = {
+  message: {
+    [Symbol.toPrimitive]: undefined,
+    toString: undefined,
+    valueOf() {
+      called += 1;
+      return 'from the valueOf method';
+    },
+  },
+  name: '',
+};
+result = false;
+
+result = method.call(obj);
+assert.sameValue(called, 1);
+assert.sameValue(result, 'from the valueOf method');

test/built-ins/AggregateError/prototype/toString/get-message-toString-symbol.js

@@ -0,0 +1,35 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  ToString(Symbol msg)
+info: |
+  AggregateError.prototype.toString ( )
+
+  1. Let O be the this value.
+  2. If Type(O) is not Object, throw a TypeError exception.
+  3. Let name be ? Get(O, "name").
+  4. If name is undefined, set name to "AggregateError"; otherwise set name to ? ToString(name).
+  5. Let msg be ? Get(O, "message").
+  6. If msg is undefined, set msg to the empty String; otherwise set msg to ? ToString(msg).
+  7. If name is the empty String, return msg.
+  8. If msg is the empty String, return name.
+  9. Return the string-concatenation of name, the code unit 0x003A (COLON), the code unit 0x0020 (SPACE) and msg.
+features: [AggregateError, Symbol]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var obj = { name: '', message: Symbol() };
+
+assert.throws(TypeError, function() {
+  method.call(obj);
+}, 'own property');
+
+obj = Object.create({ name: '', message: Symbol() });
+
+assert.throws(TypeError, function() {
+  method.call(obj);
+}, 'from prototype');

test/built-ins/AggregateError/prototype/toString/get-message-toString-undefined.js

@@ -0,0 +1,38 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  ToString(msg) where it can return "undefined"
+info: |
+  AggregateError.prototype.toString ( )
+
+  1. Let O be the this value.
+  2. If Type(O) is not Object, throw a TypeError exception.
+  3. Let name be ? Get(O, "name").
+  4. If name is undefined, set name to "AggregateError"; otherwise set name to ? ToString(name).
+  5. Let msg be ? Get(O, "message").
+  6. If msg is undefined, set msg to the empty String; otherwise set msg to ? ToString(msg).
+  7. If name is the empty String, return msg.
+  8. If msg is the empty String, return name.
+  9. Return the string-concatenation of name, the code unit 0x003A (COLON), the code unit 0x0020 (SPACE) and msg.
+features: [AggregateError]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var obj = {
+  message: {
+    toString() {
+      return undefined;
+    }
+  },
+  name: 'hi',
+};
+
+assert.sameValue(method.call(obj), 'hi\u003A\u0020undefined', 'with name');
+
+obj.name = '';
+
+assert.sameValue(method.call(obj), 'undefined', 'without name');

test/built-ins/AggregateError/prototype/toString/get-message-toString.js

@@ -0,0 +1,36 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  ToString(message)
+info: |
+  AggregateError.prototype.toString ( )
+
+  1. Let O be the this value.
+  2. If Type(O) is not Object, throw a TypeError exception.
+  3. Let name be ? Get(O, "name").
+  4. If name is undefined, set name to "AggregateError"; otherwise set name to ? ToString(name).
+  5. Let msg be ? Get(O, "message").
+  6. If msg is undefined, set msg to the empty String; otherwise set msg to ? ToString(msg).
+  7. If name is the empty String, return msg.
+  8. If msg is the empty String, return name.
+  9. Return the string-concatenation of name, the code unit 0x003A (COLON), the code unit 0x0020 (SPACE) and msg.
+features: [AggregateError]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var obj = { name: '' };
+
+obj.message = 0;
+assert.sameValue(method.call(obj), '0', 'Number 0');
+obj.message = null;
+assert.sameValue(method.call(obj), 'null', 'null');
+obj.message = false;
+assert.sameValue(method.call(obj), 'false', 'false');
+obj.message = true;
+assert.sameValue(method.call(obj), 'true', 'true');
+obj.message = 1;
+assert.sameValue(method.call(obj), '1', 'Number 1');

test/built-ins/AggregateError/prototype/toString/get-message-undefined.js

@@ -0,0 +1,64 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  An undefined message property value is cast to 'AggregateError'
+info: |
+  AggregateError.prototype.toString ( )
+
+  1. Let O be the this value.
+  2. If Type(O) is not Object, throw a TypeError exception.
+  3. Let name be ? Get(O, "name").
+  4. If name is undefined, set name to "AggregateError"; otherwise set name to ? ToString(name).
+  5. Let msg be ? Get(O, "message").
+  6. If msg is undefined, set msg to the empty String; otherwise set msg to ? ToString(msg).
+  7. If name is the empty String, return msg.
+  8. If msg is the empty String, return name.
+  9. Return the string-concatenation of name, the code unit 0x003A (COLON), the code unit 0x0020 (SPACE) and msg.
+features: [AggregateError]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var result = method.call({
+  message: undefined,
+});
+
+assert.sameValue(result, 'AggregateError', 'explicit from own property');
+
+result = false;
+result = method.call({});
+
+assert.sameValue(result, 'AggregateError', 'implicit');
+
+result = false;
+result = method.call(Object.create({
+  message: undefined,
+}));
+
+assert.sameValue(result, 'AggregateError', 'explicit from prototype');
+
+result = false;
+result = method.call({
+  message: undefined,
+  name: 'a name',
+});
+
+assert.sameValue(result, 'a name', 'explicit from own property, name is set');
+
+result = false;
+result = method.call({
+  name: 'a name',
+});
+
+assert.sameValue(result, 'a name', 'implicit, name is set');
+
+result = false;
+result = method.call(Object.create({
+  message: undefined,
+  name: 'a name',
+}));
+
+assert.sameValue(result, 'a name', 'explicit from prototype, name is set');

test/built-ins/AggregateError/prototype/toString/get-message.js

@@ -0,0 +1,33 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  Gets the Object message
+info: |
+  AggregateError.prototype.toString ( )
+
+  ...
+  5. Let msg be ? Get(O, "message").
+  ...
+features: [AggregateError]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var called = 0;
+var nameCalled = 0;
+var obj = {
+  get name() {
+    nameCalled += 1;
+  },
+  get message() {
+    called += 1;
+  }
+};
+
+method.call(obj);
+
+assert.sameValue(nameCalled, 1);
+assert.sameValue(called, 1);

test/built-ins/AggregateError/prototype/toString/get-name-abrupt.js

@@ -0,0 +1,33 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  Gets the Object name, returning abrupt completion
+info: |
+  AggregateError.prototype.toString ( )
+
+  1. Let O be the this value.
+  2. If Type(O) is not Object, throw a TypeError exception.
+  3. Let name be ? Get(O, "name").
+  4. If name is undefined, set name to "AggregateError"; otherwise set name to ? ToString(name).
+  ...
+features: [AggregateError]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var called = 0;
+var obj = {
+  get name() {
+    called += 1;
+    throw new Test262Error();
+  }
+};
+
+assert.throws(Test262Error, () => {
+  method.call(obj);
+});
+
+assert.sameValue(called, 1);

test/built-ins/AggregateError/prototype/toString/get-name-empty-string.js

@@ -0,0 +1,70 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  If name value is the empty string, return msg
+info: |
+  AggregateError.prototype.toString ( )
+
+  1. Let O be the this value.
+  2. If Type(O) is not Object, throw a TypeError exception.
+  3. Let name be ? Get(O, "name").
+  4. If name is undefined, set name to "AggregateError"; otherwise set name to ? ToString(name).
+  5. Let msg be ? Get(O, "message").
+  6. If msg is undefined, set msg to the empty String; otherwise set msg to ? ToString(msg).
+  7. If name is the empty String, return msg.
+  8. If msg is the empty String, return name.
+  9. Return the string-concatenation of name, the code unit 0x003A (COLON), the code unit 0x0020 (SPACE) and msg.
+features: [AggregateError]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var result = method.call({
+  name: '',
+  message: 'the message',
+});
+
+assert.sameValue(result, 'the message', 'explicit from own property');
+
+result = false;
+result = method.call(Object.create({
+  name: '',
+  message: 'the message',
+}));
+
+assert.sameValue(result, 'the message', 'explicit from prototype');
+
+result = false;
+result = method.call({
+  name: '',
+  message: '',
+});
+
+assert.sameValue(result, '', 'both name and msg are the empty string');
+
+result = false;
+result = method.call({
+  name: '',
+  message: undefined,
+});
+
+assert.sameValue(result, 'message', 'return msg');
+
+result = false;
+result = method.call({
+  name: { toString() { return ''; } },
+  message: 'the message!',
+});
+
+assert.sameValue(result, 'the message!', 'own name property is cast to an empty string');
+
+result = false;
+result = method.call(Object.create({
+  name: { toString() { return ''; } },
+  message: 'the message!',
+}));
+
+assert.sameValue(result, 'the message!', 'chained name property is cast to an empty string');

test/built-ins/AggregateError/prototype/toString/get-name-toString-object.js

@@ -0,0 +1,83 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  ToString on the name object value
+info: |
+  AggregateError.prototype.toString ( )
+
+  1. Let O be the this value.
+  2. If Type(O) is not Object, throw a TypeError exception.
+  3. Let name be ? Get(O, "name").
+  4. If name is undefined, set name to "AggregateError"; otherwise set name to ? ToString(name).
+  5. Let msg be ? Get(O, "message").
+  6. If msg is undefined, set msg to the empty String; otherwise set msg to ? ToString(msg).
+  7. If name is the empty String, return msg.
+  8. If msg is the empty String, return name.
+  9. Return the string-concatenation of name, the code unit 0x003A (COLON), the code unit 0x0020 (SPACE) and msg.
+features: [AggregateError, Symbol.toPrimitive]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var called = 0;
+var obj = {
+  name: {
+    [Symbol.toPrimitive]() {
+      called += 1;
+      return 'from @@toPrimitive';
+    },
+    toString() {
+      throw new Test262Error();
+    },
+    valueOf() {
+      throw new Test262Error();
+    },
+  },
+  message: '',
+};
+
+var result = method.call(obj);
+
+assert.sameValue(called, 1);
+assert.sameValue(result, 'from @@toPrimitive');
+
+called = 0;
+obj = {
+  name: {
+    [Symbol.toPrimitive]: undefined,
+    toString() {
+      called += 1;
+      return 'from the toString method';
+    },
+    valueOf() {
+      throw new Test262Error();
+    },
+  },
+  message: '',
+};
+result = false;
+
+result = method.call(obj);
+assert.sameValue(called, 1);
+assert.sameValue(result, 'from the toString method');
+
+called = 0;
+obj = {
+  name: {
+    [Symbol.toPrimitive]: undefined,
+    toString: undefined,
+    valueOf() {
+      called += 1;
+      return 'from the valueOf method';
+    },
+  },
+  message: '',
+};
+result = false;
+
+result = method.call(obj);
+assert.sameValue(called, 1);
+assert.sameValue(result, 'from the valueOf method');

test/built-ins/AggregateError/prototype/toString/get-name-toString-symbol.js

@@ -0,0 +1,34 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  ToString(name)
+info: |
+  AggregateError.prototype.toString ( )
+
+  1. Let O be the this value.
+  2. If Type(O) is not Object, throw a TypeError exception.
+  3. Let name be ? Get(O, "name").
+  4. If name is undefined, set name to "AggregateError"; otherwise set name to ? ToString(name).
+  5. Let msg be ? Get(O, "message").
+  6. If msg is undefined, set msg to the empty String; otherwise set msg to ? ToString(msg).
+  7. If name is the empty String, return msg.
+  8. If msg is the empty String, return name.
+  9. Return the string-concatenation of name, the code unit 0x003A (COLON), the code unit 0x0020 (SPACE) and msg.
+features: [AggregateError, Symbol]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var obj = { name: Symbol(), message: '' };
+
+assert.throws(TypeError, function() {
+  method.call(obj);
+}, 'own property');
+
+obj = Object.create({ name: Symbol(), message: '' });
+assert.throws(TypeError, function() {
+  method.call(obj);
+}, 'from prototype');

test/built-ins/AggregateError/prototype/toString/get-name-toString-undefined.js

@@ -0,0 +1,38 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  ToString(name) where it can return "undefined"
+info: |
+  AggregateError.prototype.toString ( )
+
+  1. Let O be the this value.
+  2. If Type(O) is not Object, throw a TypeError exception.
+  3. Let name be ? Get(O, "name").
+  4. If name is undefined, set name to "AggregateError"; otherwise set name to ? ToString(name).
+  5. Let msg be ? Get(O, "message").
+  6. If msg is undefined, set msg to the empty String; otherwise set msg to ? ToString(msg).
+  7. If name is the empty String, return msg.
+  8. If msg is the empty String, return name.
+  9. Return the string-concatenation of name, the code unit 0x003A (COLON), the code unit 0x0020 (SPACE) and msg.
+features: [AggregateError]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var obj = {
+  name: {
+    toString() {
+      return undefined;
+    }
+  },
+  message: '',
+};
+
+assert.sameValue(method.call(obj), 'undefined', 'without message');
+
+obj.message = 'lol';
+
+assert.sameValue(method.call(obj), 'undefined\u003A\u0020lol', 'with message');

test/built-ins/AggregateError/prototype/toString/get-name-toString.js

@@ -0,0 +1,36 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  ToString(name)
+info: |
+  AggregateError.prototype.toString ( )
+
+  1. Let O be the this value.
+  2. If Type(O) is not Object, throw a TypeError exception.
+  3. Let name be ? Get(O, "name").
+  4. If name is undefined, set name to "AggregateError"; otherwise set name to ? ToString(name).
+  5. Let msg be ? Get(O, "message").
+  6. If msg is undefined, set msg to the empty String; otherwise set msg to ? ToString(msg).
+  7. If name is the empty String, return msg.
+  8. If msg is the empty String, return name.
+  9. Return the string-concatenation of name, the code unit 0x003A (COLON), the code unit 0x0020 (SPACE) and msg.
+features: [AggregateError]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var obj = { message: '' };
+
+obj.name = 0;
+assert.sameValue(method.call(obj), '0', 'Number 0');
+obj.name = null;
+assert.sameValue(method.call(obj), 'null', 'null');
+obj.name = false;
+assert.sameValue(method.call(obj), 'false', 'false');
+obj.name = true;
+assert.sameValue(method.call(obj), 'true', 'true');
+obj.name = 1;
+assert.sameValue(method.call(obj), '1', 'Number 1');

test/built-ins/AggregateError/prototype/toString/get-name-undefined.js

@@ -0,0 +1,68 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  An undefined name property value is cast to 'AggregateError'
+info: |
+  AggregateError.prototype.toString ( )
+
+  1. Let O be the this value.
+  2. If Type(O) is not Object, throw a TypeError exception.
+  3. Let name be ? Get(O, "name").
+  4. If name is undefined, set name to "AggregateError"; otherwise set name to ? ToString(name).
+  5. Let msg be ? Get(O, "message").
+  6. If msg is undefined, set msg to the empty String; otherwise set msg to ? ToString(msg).
+  7. If name is the empty String, return msg.
+  8. If msg is the empty String, return name.
+  9. Return the string-concatenation of name, the code unit 0x003A (COLON), the code unit 0x0020 (SPACE) and msg.
+features: [AggregateError]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var result = method.call({
+  name: undefined,
+  message: '',
+});
+
+assert.sameValue(result, 'AggregateError', 'explicit from own property');
+
+result = false;
+result = method.call({
+  message: '',
+});
+
+assert.sameValue(result, 'AggregateError', 'implicit');
+
+result = false;
+result = method.call(Object.create({
+  name: undefined,
+  message: '',
+}));
+
+assert.sameValue(result, 'AggregateError', 'explicit from prototype');
+
+result = false;
+result = method.call({
+  name: undefined,
+  message: 'a message',
+});
+
+assert.sameValue(result, 'AggregateError\u003A\u0020a message', 'explicit from own property, message is set');
+
+result = false;
+result = method.call({
+  message: 'a message',
+});
+
+assert.sameValue(result, 'AggregateError\u003A\u0020a message', 'implicit, message is set');
+
+result = false;
+result = method.call(Object.create({
+  name: undefined,
+  message: 'a message',
+}));
+
+assert.sameValue(result, 'AggregateError\u003A\u0020a message', 'explicit from prototype, message is set');

test/built-ins/AggregateError/prototype/toString/get-name.js

@@ -0,0 +1,30 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  Gets the Object name
+info: |
+  AggregateError.prototype.toString ( )
+
+  1. Let O be the this value.
+  2. If Type(O) is not Object, throw a TypeError exception.
+  3. Let name be ? Get(O, "name").
+  4. If name is undefined, set name to "AggregateError"; otherwise set name to ? ToString(name).
+  ...
+features: [AggregateError]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var called = 0;
+var obj = {
+  get name() {
+    called += 1;
+  }
+};
+
+method.call(obj);
+
+assert.sameValue(called, 1);

test/built-ins/AggregateError/prototype/toString/length.js

@@ -0,0 +1,31 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  Property descriptor of AggregateError.prototype.toString.length
+info: |
+  AggregateError.prototype.toString
+
+  17 ECMAScript Standard Built-in Objects:
+    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. However, rest parameters shown using the form “...name”
+    are not included in the default argument count.
+
+    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: [AggregateError]
+---*/
+
+verifyProperty(AggregateError.prototype.toString, 'length', {
+  value: 0,
+  enumerable: false,
+  writable: false,
+  configurable: true
+});

test/built-ins/AggregateError/prototype/toString/name.js

@@ -0,0 +1,24 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  Property descriptor of AggregateError.prototype.toString.name
+info: |
+  AggregateError.prototype.toString
+
+  17 ECMAScript Standard Built-in Objects
+
+  Functions that are specified as get or set accessor functions of built-in
+  properties have "get " or "set " prepended to the property name string.
+includes: [propertyHelper.js]
+features: [AggregateError]
+---*/
+
+verifyProperty(AggregateError.prototype.toString, 'name', {
+  value: 'toString',
+  enumerable: false,
+  writable: false,
+  configurable: true
+});

test/built-ins/AggregateError/prototype/toString/prop-desc.js

@@ -0,0 +1,23 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  Property descriptor of AggregateError.prototype.toString
+info: |
+  ES Section 17
+
+  Every other data property (...) has the attributes { [[Writable]]: true, [[Enumerable]]: false,
+  [[Configurable]]: true } unless otherwise specified.
+includes: [propertyHelper.js]
+features: [AggregateError]
+---*/
+
+assert.sameValue(typeof AggregateError.prototype.toString, 'function');
+
+verifyProperty(AggregateError.prototype, 'toString', {
+  configurable: true,
+  writable: true,
+  enumerable: false,
+});

test/built-ins/AggregateError/prototype/toString/returns-string.js

@@ -0,0 +1,38 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  Returns a string concatenating name and msg when both are defined
+info: |
+  AggregateError.prototype.toString ( )
+
+  1. Let O be the this value.
+  2. If Type(O) is not Object, throw a TypeError exception.
+  3. Let name be ? Get(O, "name").
+  4. If name is undefined, set name to "AggregateError"; otherwise set name to ? ToString(name).
+  5. Let msg be ? Get(O, "message").
+  6. If msg is undefined, set msg to the empty String; otherwise set msg to ? ToString(msg).
+  7. If name is the empty String, return msg.
+  8. If msg is the empty String, return name.
+  9. Return the string-concatenation of name, the code unit 0x003A (COLON), the code unit 0x0020 (SPACE) and msg.
+features: [AggregateError]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+var obj = {
+  name: 'foo',
+  message: 'bar',
+};
+
+assert.sameValue(method.call(obj), 'foo\u003A\u0020bar');
+
+obj = new AggregateError(['a', 'b', 'c'], 'Hello World!');
+
+assert.sameValue(method.call(obj), 'AggregateError\u003A\u0020Hello World!');
+
+obj = new AggregateError(['a', 'b', 'c']);
+
+assert.sameValue(method.call(obj), 'AggregateError');

test/built-ins/AggregateError/prototype/toString/this-not-object-throws.js

@@ -0,0 +1,45 @@
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-aggregate-error.prototype.toString
+description: >
+  Property descriptor of AggregateError.prototype.toString
+info: |
+  AggregateError.prototype.toString ( )
+
+  1. Let O be the this value.
+  2. If Type(O) is not Object, throw a TypeError exception.
+features: [AggregateError, Symbol]
+---*/
+
+var method = AggregateError.prototype.toString;
+
+assert.throws(TypeError, () => {
+  method.call(undefined);
+}, 'undefined');
+
+assert.throws(TypeError, () => {
+  method.call(null);
+}, 'null');
+
+assert.throws(TypeError, () => {
+  method.call(false);
+}, 'false');
+
+assert.throws(TypeError, () => {
+  method.call(true);
+}, 'true');
+
+assert.throws(TypeError, () => {
+  method.call(42);
+}, 'number');
+
+assert.throws(TypeError, () => {
+  method.call('string');
+}, 'string');
+
+var s = Symbol();
+assert.throws(TypeError, () => {
+  method.call(s);
+}, 'symbol');