String.prototype.matchAll: add tests for stage 3

`String.prototype.matchAll`: Add basic tests.

test/built-ins/String/prototype/matchAll/cstm-matcher-get-err.js

+// Copyright (C) 2018 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: Behavior when error is thrown accessing @@matchAll property
+info: |
+    [...]
+    4. Let matcher be ? GetMethod(R, @@matchAll).
+    5. If matcher is not undefined, then
+      a. Return ? Call(matcher, R, « O »).
+features: [Symbol.match, Symbol.matchAll]
+---*/
+
+var obj = {};
+Object.defineProperty(obj, Symbol.match, {
+  value: true // to make IsRegExp pass
+});
+Object.defineProperty(obj, Symbol.matchAll, {
+  get: function() {
+    throw new Test262Error();
+  }
+});
+
+assert.throws(Test262Error, function() {
+  ''.matchAll(obj);
+});

test/built-ins/String/prototype/matchAll/cstm-matcher-invocation.js

+// Copyright (C) 2018 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: Invocation of @@matchAll property of user-supplied RegExp objects
+info: |
+    [...]
+    4. Let matcher be ? GetMethod(R, @@matchAll).
+    5. If matcher is not undefined, then
+      a. Return ? Call(matcher, R, « O »).
+features: [Symbol.match, Symbol.matchAll]
+---*/
+
+var obj = {};
+var returnVal = {};
+var callCount = 0;
+var thisVal, args;
+
+obj[Symbol.match] = true; // https://tc39.github.io/ecma262/#sec-isregexp steps 1-3
+obj[Symbol.matchAll] = function () {
+  callCount += 1;
+  thisVal = this;
+  args = arguments;
+  return returnVal;
+};
+
+var str = '';
+
+assert.sameValue(str.matchAll(obj), returnVal);
+assert.sameValue(callCount, 1, 'Invokes the method exactly once');
+assert.sameValue(thisVal, obj);
+assert.notSameValue(args, undefined);
+assert.sameValue(args.length, 1);
+assert.sameValue(args[0], str);

test/built-ins/String/prototype/matchAll/invoke-builtin-matchall.js

+// Copyright (C) 2018 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: Invocation of @@matchAll property of internally-created RegExps
+info: |
+    [...]
+    3. Else,
+      a. Let R be ? RegExpCreate(regexp, "g").
+    4. Let matcher be ? GetMethod(R, @@matchAll).
+    5. If matcher is not undefined, then
+      a. Return ? Call(matcher, R, « O »).
+    6. Return ? MatchAllIterator(R, O).
+features: [Symbol.match, Symbol.matchAll]
+---*/
+
+var originalMatchAll = RegExp.prototype[Symbol.matchAll];
+var returnVal = {};
+var result, thisVal, args;
+
+RegExp.prototype[Symbol.matchAll] = function() {
+  thisVal = this;
+  args = arguments;
+  return returnVal;
+};
+
+var str = 'target';
+var stringToMatch = 'string source';
+
+try {
+  result = str.matchAll(stringToMatch);
+
+  assert(thisVal instanceof RegExp);
+  assert.sameValue(!!thisVal[Symbol.match], true);
+  assert.sameValue(thisVal.source, stringToMatch);
+  assert.sameValue(thisVal.flags, 'g');
+  assert.sameValue(thisVal.lastIndex, 0);
+  assert.sameValue(args.length, 1);
+  assert.sameValue(args[0], str);
+  assert.sameValue(result, returnVal);
+} finally {
+  RegExp.prototype[Symbol.matchAll] = originalMatchAll;
+}

test/built-ins/String/prototype/matchAll/length.js

+// Copyright (C) 2018 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Length of String.prototype.matchAll
+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(String.prototype.matchAll.length, 1);
+
+verifyNotEnumerable(String.prototype.matchAll, 'length');
+verifyNotWritable(String.prototype.matchAll, 'length');
+verifyConfigurable(String.prototype.matchAll, 'length');

test/built-ins/String/prototype/matchAll/name.js

+// Copyright (C) 2018 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Descriptor for `name` property
+info: |
+  The value of the name property of this function is "matchAll".
+
+  ES6 Section 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.
+
+  [...]
+
+  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(String.prototype[Symbol.iterator].name, 'matchAll');
+
+verifyNotEnumerable(String.prototype[Symbol.iterator], 'name');
+verifyNotWritable(String.prototype[Symbol.iterator], 'name');
+verifyConfigurable(String.prototype[Symbol.iterator], 'name');

test/built-ins/String/prototype/matchAll/prop-desc.js

+// Copyright (C) 2018 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: Property descriptor
+info: |
+    ES6 Section 17
+
+    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.
+features: [Symbol.iterator]
+includes: [propertyHelper.js]
+---*/
+
+assert.sameValue(typeof String.prototype.matchAll, 'function');
+verifyNotEnumerable(String.prototype, 'matchAll');
+verifyWritable(String.prototype, 'matchAll');
+verifyConfigurable(String.prototype, 'matchAll');

test/built-ins/String/prototype/matchAll/this-val-non-obj-coercible.js

+// Copyright (C) 2018 Jordan Harband. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: The `this` value cannot be coerced into an object
+info: |
+    1. Let O be RequireObjectCoercible(this value).
+    2. Let S be ToString(O).
+    3. ReturnIfAbrupt(S).
+features: [Symbol.iterator]
+---*/
+
+var matchAll = String.prototype.matchAll;
+
+assert.sameValue(typeof matchAll, 'function');
+
+assert.throws(TypeError, function() {
+  matchAll.call(undefined);
+}, 'undefined');
+
+assert.throws(TypeError, function() {
+  matchAll.call(null);
+}, 'null');