start of flatMap tests

Author: michaelficarra

test/built-ins/Iterator/prototype/every/this-non-callable-next.js

@@ -14,5 +14,5 @@ features: [iterator-helpers]
 flags: []
 ---*/
 assert.throws(TypeError, function() {
-  Iterator.prototype.every.call({ next: 0 }, () => {});
+  Iterator.prototype.every.call({ next: 0 }, () => true);
 });

test/built-ins/Iterator/prototype/filter/name.js

@@ -7,7 +7,7 @@ description: >
 info: |
   17 ECMAScript Standard Built-in Objects
 
-  filter built-in Function object, including constructors, that is not
+  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.

test/built-ins/Iterator/prototype/filter/non-constructible.js

@@ -18,5 +18,5 @@ assert.throws(TypeError, () => {
 }, '`new Iterator.prototype.filter(() => true)` throws a TypeError exception');
 
 assert.throws(TypeError, () => {
-  new (class extends Iterator {}).filter(() => {});
+  new (class extends Iterator {}).filter(() => true);
 }, '`new (new class extends Iterator {}).filter(() => true)` throws a TypeError exception');

test/built-ins/Iterator/prototype/filter/this-non-callable-next.js

@@ -14,5 +14,5 @@ features: [iterator-helpers]
 flags: []
 ---*/
 assert.throws(TypeError, function() {
-  Iterator.prototype.filter.call({ next: 0 }, 1);
+  Iterator.prototype.filter.call({ next: 0 }, () => true);
 });

test/built-ins/Iterator/prototype/flatMap/argument-effect-order.js

@@ -0,0 +1,31 @@
+// Copyright (C) 2023 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iteratorprototype.flatMap
+description: >
+  Arguments and this value are evaluated in the correct order
+info: |
+  %Iterator.prototype%.flatMap ( mapper )
+
+includes: [iterators.js, compareArray.js]
+features: [iterator-helpers]
+flags: []
+---*/
+let effects = [];
+
+assert.throws(TypeError, function() {
+  Iterator.prototype.flatMap.call(
+    {
+      get next() {
+        effects.push('get next');
+        return function() {
+          return { done: true, value: undefined };
+        };
+      }
+    },
+    null
+  );
+});
+
+assert.compareArray(effects, [
+]);

test/built-ins/Iterator/prototype/flatMap/callable.js

@@ -0,0 +1,13 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iteratorprototype.flatMap
+description: >
+  Iterator.prototype.flatMap is callable
+features: [iterator-helpers]
+---*/
+function* g() {}
+Iterator.prototype.flatMap.call(g(), () => []);
+
+let iter = g();
+iter.flatMap(() => []);

test/built-ins/Iterator/prototype/flatMap/exhaustion-does-not-call-return.js

@@ -0,0 +1,43 @@
+// Copyright (C) 2023 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iteratorprototype.flatMap
+description: >
+  Underlying iterator return is not called when result iterator is exhausted
+info: |
+  %Iterator.prototype%.flatMap ( mapper )
+
+includes: [iterators.js]
+features: [iterator-helpers]
+flags: []
+---*/
+class TestIterator extends Iterator {
+  constructor() {
+    super();
+    this._remaining = 3;
+  }
+  next() {
+    if (this._remaining > 0) {
+      return {
+        done: false,
+        value: this._remaining--
+      };
+    } else {
+      return {
+        done: true,
+        value: undefined
+      };
+    }
+  }
+  return() {
+    if (this._remaining <= 0) {
+      throw new Test262Error;
+    }
+    return {};
+  }
+}
+
+let iterator = new TestIterator().flatMap(() => []);
+iterator.next();
+iterator.next();
+iterator.next();

test/built-ins/Iterator/prototype/flatMap/get-next-method-only-once.js

@@ -0,0 +1,40 @@
+// Copyright (C) 2023 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iteratorprototype.flatMap
+description: >
+  Gets the next method from the underlying iterator only once
+info: |
+  %Iterator.prototype%.flatMap ( mapper )
+
+includes: [iterators.js]
+features: [iterator-helpers]
+flags: []
+---*/
+let nextGets = 0;
+let nextCalls = 0;
+
+class CountingIterator extends Iterator {
+  get next() {
+    nextGets++;
+    let iter = function* () {
+      for (let i = 1; i < 5; ++i) {
+        yield i;
+      }
+    }();
+    return function () {
+      nextCalls++;
+      return iter.next();
+    };
+  }
+}
+
+let iterator = new CountingIterator;
+
+assert.sameValue(nextGets, 0, 'The value of `nextGets` is 0');
+assert.sameValue(nextCalls, 0, 'The value of `nextCalls` is 0');
+
+for (const value of iterator.flatMap(() => []));
+
+assert.sameValue(nextGets, 1, 'The value of `nextGets` is 1');
+assert.sameValue(nextCalls, 5, 'The value of `nextCalls` is 5');

test/built-ins/Iterator/prototype/flatMap/get-next-method-throws.js

@@ -0,0 +1,24 @@
+// Copyright (C) 2023 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iteratorprototype.flatMap
+description: >
+  Underlying iterator has throwing next getter
+info: |
+  %Iterator.prototype%.flatMap ( mapper )
+
+includes: [iterators.js]
+features: [iterator-helpers]
+flags: []
+---*/
+class ThrowingIterator extends Iterator {
+  get next() {
+    throw new Test262Error;
+  }
+}
+
+let iterator = new ThrowingIterator;
+
+assert.throws(Test262Error, function () {
+  iterator.flatMap(() => []);
+});

test/built-ins/Iterator/prototype/flatMap/get-return-method-throws.js

@@ -0,0 +1,31 @@
+// Copyright (C) 2023 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iteratorprototype.flatMap
+description: >
+  Underlying iterator return is throwing getter
+info: |
+  %Iterator.prototype%.flatMap ( mapper )
+
+includes: [iterators.js]
+features: [iterator-helpers]
+flags: []
+---*/
+class TestIterator extends Iterator {
+  next() {
+    return {
+      done: false,
+      value: 1
+    };
+  }
+  get return() {
+    throw new Test262Error;
+  }
+}
+
+let iterator = new TestIterator().flatMap(x => [x]);
+iterator.next();
+
+assert.throws(Test262Error, function() {
+  iterator.return();
+});

test/built-ins/Iterator/prototype/flatMap/is-function.js

@@ -0,0 +1,10 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iteratorprototype.flatMap
+description: >
+  Iterator.prototype.flatMap is a built-in function
+features: [iterator-helpers]
+---*/
+
+assert.sameValue(typeof Iterator.prototype.flatMap, 'function', 'The value of `typeof Iterator.prototype.flatMap` is "function"');

test/built-ins/Iterator/prototype/flatMap/iterator-already-exhausted.js

@@ -0,0 +1,23 @@
+// Copyright (C) 2023 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iteratorprototype.flatMap
+description: >
+  Iterator.prototype.flatMap returns an empty iterator when the iterator has already been exhausted
+info: |
+  %Iterator.prototype%.flatMap ( mapper )
+
+includes: [iterators.js]
+features: [iterator-helpers]
+flags: []
+---*/
+let iterator = new Test262Iterator([]);
+
+let {value, done} = iterator.next();
+assert.sameValue(value, undefined, 'The value of `value` is expected to equal `undefined`');
+assert.sameValue(done, true, 'The value of `done` is true');
+
+iterator = iterator.flatMap(x => [x]);
+({value, done} = iterator.next());
+assert.sameValue(value, undefined, 'The value of `value` is expected to equal `undefined`');
+assert.sameValue(done, true, 'The value of `done` is true');

test/built-ins/Iterator/prototype/flatMap/iterator-return-method-throws.js

@@ -0,0 +1,24 @@
+// Copyright (C) 2023 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iteratorprototype.flatMap
+description: >
+  Iterator has throwing return
+info: |
+  %Iterator.prototype%.flatMap ( mapper )
+
+includes: [iterators.js]
+features: [iterator-helpers]
+flags: []
+---*/
+class Test262IteratorThrows extends Test262Iterator {
+  return() {
+    throw new Test262Error();
+  }
+}
+
+let iterator = new Test262IteratorThrows([1, 2]).flatMap(() => []);
+
+assert.throws(Test262Error, function() {
+  iterator.return();
+});

test/built-ins/Iterator/prototype/flatMap/length.js

@@ -0,0 +1,21 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iteratorprototype.flatMap
+description: >
+  Iterator.prototype.flatMap has a "length" property whose value is 0.
+info: |
+  ECMAScript Standard Built-in Objects
+
+  Unless otherwise specified, the length property of a built-in
+  Function object has the attributes { [[Writable]]: false, [[Enumerable]]:
+  false, [[Configurable]]: true }.
+features: [iterator-helpers]
+includes: [propertyHelper.js]
+---*/
+
+assert.sameValue(Iterator.prototype.flatMap.length, 1, 'The value of Iterator.prototype.flatMap.length is 1');
+
+verifyNotEnumerable(Iterator.prototype.flatMap, 'length');
+verifyNotWritable(Iterator.prototype.flatMap, 'length');
+verifyConfigurable(Iterator.prototype.flatMap, 'length');

test/built-ins/Iterator/prototype/flatMap/mapper-args.js

@@ -0,0 +1,43 @@
+// Copyright (C) 2023 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iteratorprototype.flatMap
+description: >
+  Iterator.prototype.flatMap mapper is passed the yielded value and a counter as arguments
+info: |
+  %Iterator.prototype%.flatMap ( mapper )
+
+includes: [iterators.js]
+features: [iterator-helpers]
+flags: []
+---*/
+function* g() {
+  yield 'a';
+  yield 'b';
+  yield 'c';
+}
+
+let assertionCount = 0;
+let iter = g().flatMap((v, count) => {
+  switch (v) {
+    case 'a':
+      assert.sameValue(count, 0);
+      break;
+    case 'b':
+      assert.sameValue(count, 1);
+      break;
+    case 'c':
+      assert.sameValue(count, 2);
+      break;
+    default:
+      throw new Error;
+  }
+  ++assertionCount;
+  return [v];
+});
+
+assert.sameValue(assertionCount, 0);
+
+for (let i of iter);
+
+assert.sameValue(assertionCount, 3);

test/built-ins/Iterator/prototype/flatMap/mapper-returns-non-object.js

@@ -0,0 +1,35 @@
+// Copyright (C) 2023 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iteratorprototype.flatMap
+description: >
+  Iterator.prototype.flatMap mapper return value must be an object
+info: |
+  %Iterator.prototype%.flatMap ( mapper )
+
+includes: [iterators.js]
+features: [iterator-helpers]
+flags: []
+---*/
+function* g() {
+  yield 0;
+  yield 0;
+  yield 0;
+  yield 1;
+}
+
+let iter = g();
+
+let mapperCalls = 0;
+iter = iter.flatMap(v => {
+  ++mapperCalls;
+  return null;
+});
+
+assert.sameValue(mapperCalls, 0);
+
+assert.throws(TypeError, function() {
+  iter.next();
+});
+
+assert.sameValue(mapperCalls, 1);