Add tests for Array.from

Limit tests to behavior of method when invoked with an iterable.

test/built-ins/Array/from/get-iter-method-err.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 22.1.2.1
+description: Error accessing items' `Symbol.iterator` attribute
+info: >
+    [...]
+    4. Let usingIterator be GetMethod(items, @@iterator).
+    5. ReturnIfAbrupt(usingIterator).
+features: [Symbol.iterator]
+---*/
+
+var items = {};
+Object.defineProperty(items, Symbol.iterator, {
+  get: function() {
+    throw new Test262Error();
+  }
+});
+
+assert.throws(Test262Error, function() {
+  Array.from(items);
+});

test/built-ins/Array/from/iter-adv-err.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 22.1.2.1
+description: Error advancing iterator
+info: >
+    [...]
+    6. If usingIterator is not undefined, then
+       [...]
+       g. Repeat
+          i. Let Pk be ToString(k).
+          ii. Let next be IteratorStep(iterator).
+          iii. ReturnIfAbrupt(next).
+features: [Symbol.iterator]
+---*/
+
+var items = {};
+items[Symbol.iterator] = function() {
+  return {
+    next: function() {
+      throw new Test262Error();
+    }
+  };
+};
+
+assert.throws(Test262Error, function() {
+  Array.from(items);
+});

test/built-ins/Array/from/iter-cstm-ctor-err.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 22.1.2.1
+description: >
+    Error creating object with custom constructor (traversed via iterator)
+info: >
+    [...]
+    6. If usingIterator is not undefined, then
+       a. If IsConstructor(C) is true, then
+          i. Let A be Construct(C).
+       b. Else,
+          i. Let A be ArrayCreate(0).
+       c. ReturnIfAbrupt(A).
+features: [Symbol.iterator]
+---*/
+
+var C = function() {
+  throw new Test262Error();
+};
+var items = {};
+items[Symbol.iterator] = function() {};
+
+assert.throws(Test262Error, function() {
+  Array.from.call(C, items);
+});

test/built-ins/Array/from/iter-cstm-ctor.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 22.1.2.1
+description: Creating object with custom constructor (traversed via iterator)
+info: >
+    [...]
+    6. If usingIterator is not undefined, then
+       a. If IsConstructor(C) is true, then
+          i. Let A be Construct(C).
+       b. Else,
+          i. Let A be ArrayCreate(0).
+       c. ReturnIfAbrupt(A).
+features: [Symbol.iterator]
+---*/
+
+var thisVal, args;
+var callCount = 0;
+var C = function() {
+  thisVal = this;
+  args = arguments;
+  callCount += 1;
+};
+var result;
+var items = {};
+items[Symbol.iterator] = function() {
+  return {
+    next: function() {
+      return { done: true };
+    }
+  };
+};
+
+result = Array.from.call(C, items);
+
+assert(
+  result instanceof C, 'Constructed value is an instance of the constructor'
+);
+assert.sameValue(
+  result.constructor,
+  C,
+  'Constructed value correctly defines a `constructor` property'
+);
+assert.sameValue(callCount, 1, 'Constructor invoked exactly once');
+assert.sameValue(thisVal, result, 'Constructed value is returned');
+assert.sameValue(args.length, 0, 'Constructor invoked without arguments');

test/built-ins/Array/from/iter-get-iter-err.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 22.1.2.1
+description: Error creating iterator object
+info: >
+    [...]
+    6. If usingIterator is not undefined, then
+       [...]
+       d. Let iterator be GetIterator(items, usingIterator).
+       e. ReturnIfAbrupt(iterator).
+features: [Symbol.iterator]
+---*/
+
+var items = {};
+items[Symbol.iterator] = function() {
+  throw new Test262Error();
+};
+
+assert.throws(Test262Error, function() {
+  Array.from(items);
+});

test/built-ins/Array/from/iter-get-iter-val-err.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 22.1.2.1
+description: Error retrieving value of iterator result
+info: >
+    [...]
+    6. If usingIterator is not undefined, then
+       [...]
+       g. Repeat
+          [...]
+          v. Let nextValue be IteratorValue(next).
+          vi. ReturnIfAbrupt(nextValue).
+features: [Symbol.iterator]
+---*/
+
+var items = {};
+var poisonedValue = {};
+Object.defineProperty(poisonedValue, 'value', {
+  get: function() {
+    throw new Test262Error();
+  }
+});
+items[Symbol.iterator] = function() {
+  return {
+    next: function() {
+      return poisonedValue;
+    }
+  };
+};
+
+assert.throws(Test262Error, function() {
+  Array.from(items);
+});

test/built-ins/Array/from/iter-map-fn-args.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 22.1.2.1
+description: >
+    Arguments of mapping function (traversed via iterator)
+info: >
+    [...]
+    2. If mapfn is undefined, let mapping be false.
+    3. else
+       a. If IsCallable(mapfn) is false, throw a TypeError exception.
+       b. If thisArg was supplied, let T be thisArg; else let T be undefined.
+       c. Let mapping be true
+    [...]
+    6. If usingIterator is not undefined, then
+       [...]
+       g. Repeat
+          [...]
+          vii. If mapping is true, then
+               1. Let mappedValue be Call(mapfn, T, «nextValue, k»).
+               2. If mappedValue is an abrupt completion, return
+                  IteratorClose(iterator, mappedValue).
+               3. Let mappedValue be mappedValue.[[value]].
+features: [Symbol.iterator]
+---*/
+
+var args = [];
+var firstResult = { done: false, value: {} };
+var secondResult = { done: false, value: {} };
+var mapFn = function(value, idx) {
+  args.push(arguments);
+};
+var items = {};
+var nextResult = firstResult;
+var nextNextResult = secondResult;
+
+items[Symbol.iterator] = function() {
+  return {
+    next: function() {
+      var result = nextResult;
+      nextResult = nextNextResult;
+      nextNextResult = { done: true };
+
+      return result;
+    }
+  };
+};
+
+Array.from(items, mapFn);
+
+assert.sameValue(args.length, 2, 'Iteration count');
+
+assert.sameValue(args[0].length, 2, 'First iteration: arguments length');
+assert.sameValue(
+  args[0][0], firstResult.value, 'First iteration: first argument'
+);
+assert.sameValue(args[0][1], 0, 'First iteration: second argument');
+
+assert.sameValue(args[1].length, 2, 'Second iteration: arguments length');
+assert.sameValue(
+  args[1][0], secondResult.value, 'Second iteration: first argument'
+);
+assert.sameValue(args[1][1], 1, 'Second iteration: second argument');

test/built-ins/Array/from/iter-map-fn-err.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 22.1.2.1
+description: Error invoking map function (traversed via iterator)
+info: >
+    [...]
+    6. If usingIterator is not undefined, then
+       [...]
+       g. Repeat
+          [...]
+          vii. If mapping is true, then
+               1. Let mappedValue be Call(mapfn, T, «nextValue, k»).
+               2. If mappedValue is an abrupt completion, return
+                  IteratorClose(iterator, mappedValue).
+features: [Symbol.iterator]
+---*/
+
+var closeCount = 0;
+var mapFn = function() {
+  throw new Test262Error();
+};
+var items = {};
+items[Symbol.iterator] = function() {
+  return {
+    return: function() {
+      closeCount += 1;
+    },
+    next: function() {
+      return {
+        done: false
+      };
+    }
+  };
+};
+
+assert.throws(Test262Error, function() {
+  Array.from(items, mapFn);
+});
+
+assert.sameValue(closeCount, 1);

test/built-ins/Array/from/iter-map-fn-return.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 22.1.2.1
+description: Value returned by mapping function (traversed via iterator)
+info: >
+    [...]
+    2. If mapfn is undefined, let mapping be false.
+    3. else
+       a. If IsCallable(mapfn) is false, throw a TypeError exception.
+       b. If thisArg was supplied, let T be thisArg; else let T be undefined.
+       c. Let mapping be true
+    [...]
+    6. If usingIterator is not undefined, then
+       [...]
+       g. Repeat
+          [...]
+          vii. If mapping is true, then
+               1. Let mappedValue be Call(mapfn, T, «nextValue, k»).
+               2. If mappedValue is an abrupt completion, return
+                  IteratorClose(iterator, mappedValue).
+               3. Let mappedValue be mappedValue.[[value]].
+features: [Symbol.iterator]
+---*/
+
+var thisVals = [];
+var nextResult = { done: false, value: {} };
+var nextNextResult = { done: false, value: {} };
+var firstReturnVal = {};
+var secondReturnVal = {};
+var mapFn = function(value, idx) {
+  var returnVal = nextReturnVal;
+  nextReturnVal = nextNextReturnVal;
+  nextNextReturnVal = null;
+  return returnVal;
+};
+var nextReturnVal = firstReturnVal;
+var nextNextReturnVal = secondReturnVal;
+var items = {};
+var result;
+
+items[Symbol.iterator] = function() {
+  return {
+    next: function() {
+      var result = nextResult;
+      nextResult = nextNextResult;
+      nextNextResult = { done: true };
+
+      return result;
+    }
+  };
+};
+
+result = Array.from(items, mapFn);
+
+assert.sameValue(result.length, 2);
+assert.sameValue(result[0], firstReturnVal);
+assert.sameValue(result[1], secondReturnVal);

test/built-ins/Array/from/iter-map-fn-this-arg.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 22.1.2.1
+description: >
+    `this` value of mapping function with custom `this` argument (traversed via iterator)
+info: >
+    [...]
+    2. If mapfn is undefined, let mapping be false.
+    3. else
+       a. If IsCallable(mapfn) is false, throw a TypeError exception.
+       b. If thisArg was supplied, let T be thisArg; else let T be undefined.
+       c. Let mapping be true
+    [...]
+    6. If usingIterator is not undefined, then
+       [...]
+       g. Repeat
+          [...]
+          vii. If mapping is true, then
+               1. Let mappedValue be Call(mapfn, T, «nextValue, k»).
+features: [Symbol.iterator]
+---*/
+
+var thisVals = [];
+var nextResult = { done: false, value: {} };
+var nextNextResult = { done: false, value: {} };
+var mapFn = function() {
+  thisVals.push(this);
+};
+var items = {};
+var thisVal = {};
+
+items[Symbol.iterator] = function() {
+  return {
+    next: function() {
+      var result = nextResult;
+      nextResult = nextNextResult;
+      nextNextResult = { done: true };
+
+      return result;
+    }
+  };
+};
+
+Array.from(items, mapFn, thisVal);
+
+assert.sameValue(thisVals.length, 2);
+assert.sameValue(thisVals[0], thisVal, 'First iteration `this` value');
+assert.sameValue(thisVals[1], thisVal, 'Second iteration `this` value');

test/built-ins/Array/from/iter-map-fn-this-non-strict.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 22.1.2.1
+description: >
+    `this` value of mapping function in non-strict mode (traversed via iterator)
+info: >
+    [...]
+    2. If mapfn is undefined, let mapping be false.
+    3. else
+       a. If IsCallable(mapfn) is false, throw a TypeError exception.
+       b. If thisArg was supplied, let T be thisArg; else let T be undefined.
+       c. Let mapping be true
+    [...]
+    6. If usingIterator is not undefined, then
+       [...]
+       g. Repeat
+          [...]
+          vii. If mapping is true, then
+               1. Let mappedValue be Call(mapfn, T, «nextValue, k»).
+features: [Symbol.iterator]
+flags: [noStrict]
+---*/
+
+var thisVals = [];
+var nextResult = { done: false, value: {} };
+var nextNextResult = { done: false, value: {} };
+var mapFn = function() {
+  thisVals.push(this);
+};
+var items = {};
+var global = function() { return this; }();
+
+items[Symbol.iterator] = function() {
+  return {
+    next: function() {
+      var result = nextResult;
+      nextResult = nextNextResult;
+      nextNextResult = { done: true };
+
+      return result;
+    }
+  };
+};
+
+Array.from(items, mapFn);
+
+assert.sameValue(thisVals.length, 2);
+assert.sameValue(thisVals[0], global, 'First iteration `this` value');
+assert.sameValue(thisVals[1], global, 'Second iteration `this` value');

test/built-ins/Array/from/iter-map-fn-this-strict.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 22.1.2.1
+description: >
+    `this` value of mapping function in strict mode (traversed via iterator)
+info: >
+    [...]
+    2. If mapfn is undefined, let mapping be false.
+    3. else
+       a. If IsCallable(mapfn) is false, throw a TypeError exception.
+       b. If thisArg was supplied, let T be thisArg; else let T be undefined.
+       c. Let mapping be true
+    [...]
+    6. If usingIterator is not undefined, then
+       [...]
+       g. Repeat
+          [...]
+          vii. If mapping is true, then
+               1. Let mappedValue be Call(mapfn, T, «nextValue, k»).
+features: [Symbol.iterator]
+flags: [onlyStrict]
+---*/
+
+var thisVals = [];
+var nextResult = { done: false, value: {} };
+var nextNextResult = { done: false, value: {} };
+var mapFn = function() {
+  thisVals.push(this);
+};
+var items = {};
+
+items[Symbol.iterator] = function() {
+  return {
+    next: function() {
+      var result = nextResult;
+      nextResult = nextNextResult;
+      nextNextResult = { done: true };
+
+      return result;
+    }
+  };
+};
+
+Array.from(items, mapFn);
+
+assert.sameValue(thisVals.length, 2);
+assert.sameValue(thisVals[0], undefined, 'First iteration `this` value');
+assert.sameValue(thisVals[1], undefined, 'Second iteration `this` value');

test/built-ins/Array/from/iter-set-elem-prop-err.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 22.1.2.1
+description: Error setting property on result value (traversed via iterator)
+info: >
+    [...]
+    6. If usingIterator is not undefined, then
+       [...]
+       g. Repeat
+          [...]
+          ix. Let defineStatus be CreateDataPropertyOrThrow(A, Pk,
+              mappedValue).
+          x. If defineStatus is an abrupt completion, return
+             IteratorClose(iterator, defineStatus).
+features: [Symbol.iterator]
+---*/
+
+var C = function() {
+  Object.defineProperty(this, '0', { configurable: false });
+};
+var closeCount = 0;
+var items = {};
+var nextResult = { done: false };
+
+items[Symbol.iterator] = function() {
+  return {
+    return: function() {
+      closeCount += 1;
+    },
+    next: function() {
+      var result = nextResult;
+
+      nextResult = { done: true };
+
+      return result;
+    }
+  };
+};
+
+assert.throws(TypeError, function() {
+  Array.from.call(C, items);
+});
+
+assert.sameValue(closeCount, 1);

test/built-ins/Array/from/iter-set-elem-prop.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 22.1.2.1
+description: Setting property on result value (traversed via iterator)
+info: >
+    [...]
+    6. If usingIterator is not undefined, then
+       [...]
+       g. Repeat
+          [...]
+          ix. Let defineStatus be CreateDataPropertyOrThrow(A, Pk,
+              mappedValue).
+features: [Symbol.iterator]
+---*/
+
+var items = {};
+var firstIterResult = { done: false, value: {} };
+var secondIterResult = { done: false, value: {} };
+var thirdIterResult = { done: true, value: {} };
+var nextIterResult = firstIterResult;
+var nextNextIterResult = secondIterResult;
+var result;
+
+items[Symbol.iterator] = function() {
+  return {
+    next: function() {
+      var result = nextIterResult;
+
+      nextIterResult = nextNextIterResult;
+      nextNextIterResult = thirdIterResult;
+
+      return result;
+    }
+  };
+};
+
+result = Array.from(items);
+
+assert.sameValue(result[0], firstIterResult.value);
+assert.sameValue(result[1], secondIterResult.value);

test/built-ins/Array/from/iter-set-length-err.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 22.1.2.1
+description: Error setting length of object (traversed via iterator)
+info: >
+    [...]
+    6. If usingIterator is not undefined, then
+       [...]
+       g. Repeat
+          [...]
+          iv. If next is false, then
+              1. Let setStatus be Set(A, "length", k, true).
+              2. ReturnIfAbrupt(setStatus).
+features: [Symbol.iterator]
+---*/
+
+var C = function() {};
+var items = {};
+Object.defineProperty(C.prototype, 'length', {
+  set: function(_) {
+    throw new Test262Error();
+  }
+});
+items[Symbol.iterator] = function() {
+  return {
+    next: function() { return { done: true }; }
+  };
+};
+
+assert.throws(Test262Error, function() {
+  Array.from.call(C, items);
+});

test/built-ins/Array/from/iter-set-length.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 22.1.2.1
+description: Setting length of object (traversed via iterator)
+info: >
+    [...]
+    6. If usingIterator is not undefined, then
+       [...]
+       g. Repeat
+          [...]
+          iv. If next is false, then
+              1. Let setStatus be Set(A, "length", k, true).
+              2. ReturnIfAbrupt(setStatus).
+              3. Return A.
+features: [Symbol.iterator]
+---*/
+
+var items = {};
+var result, nextIterResult, lastIterResult;
+items[Symbol.iterator] = function() {
+  return {
+    next: function() {
+      var result = nextIterResult;
+      nextIterResult = lastIterResult;
+      return result;
+    }
+  };
+};
+
+nextIterResult = lastIterResult = { done: true };
+result = Array.from(items);
+
+assert.sameValue(result.length, 0);
+
+nextIterResult = { done: false };
+lastIterResult = { done: true };
+result = Array.from(items);
+
+assert.sameValue(result.length, 1);