iterator includes tests

Author: michaelficarra

features.txt

@@ -159,6 +159,7 @@ hashbang
 import-attributes
 import.meta
 iterator-helpers
+iterator-includes
 iterator-sequencing
 Int8Array
 Int16Array

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

@@ -0,0 +1,67 @@
+// Copyright (C) 2026 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iterator.prototype.includes
+description: >
+  Arguments and this value are validated in the correct order
+info: |
+  Iterator.prototype.includes ( searchElement [ , skippedElements ] )
+
+  1. Let O be the this value.
+  2. If O is not an Object, throw a TypeError exception.
+  3. Let iterated be the Iterator Record { [[Iterator]]: O, [[NextMethod]]: undefined, [[Done]]: false }.
+  4. If skippedElements is undefined, let toSkip be 0.
+  5. Else if skippedElements is not one of +Infinity, -Infinity, or an integral Number,
+    a. Let error be ThrowCompletion(a newly created TypeError object).
+    b. Return ? IteratorClose(iterated, error).
+  9. Set iterated to ? GetIteratorDirect(O).
+
+includes: [compareArray.js]
+features: [iterator-includes]
+---*/
+
+let effects = [];
+
+assert.throws(TypeError, function() {
+  Iterator.prototype.includes.call(null, 0, NaN);
+});
+
+assert.compareArray(effects, []);
+
+assert.throws(TypeError, function() {
+  Iterator.prototype.includes.call(
+    {
+      get next() {
+        effects.push('get next');
+        return function() {
+          return { done: true, value: undefined };
+        };
+      },
+      return() {
+        effects.push('return');
+        return {};
+      },
+    },
+    0,
+    NaN
+  );
+});
+
+assert.compareArray(effects, ['return']);
+
+effects = [];
+
+Iterator.prototype.includes.call(
+  {
+    get next() {
+      effects.push('get next');
+      return function() {
+        return { done: true, value: undefined };
+      };
+    },
+  },
+  0,
+  0
+);
+
+assert.compareArray(effects, ['get next']);

test/built-ins/Iterator/prototype/includes/argument-validation-failure-closes-underlying.js

@@ -0,0 +1,31 @@
+// Copyright (C) 2026 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iterator.prototype.includes
+description: >
+  Underlying iterator is closed when skippedElements validation fails
+features: [iterator-includes]
+---*/
+
+let closed = false;
+let closable = {
+  __proto__: Iterator.prototype,
+  get next() {
+    throw new Test262Error('next should not be read');
+  },
+  return() {
+    closed = true;
+    return {};
+  },
+};
+
+assert.throws(RangeError, function() {
+  closable.includes(null, -2);
+});
+assert.sameValue(closed, true, 'iterator closed when skippedElements validation produces a RangeError');
+
+closed = false;
+assert.throws(TypeError, function() {
+  closable.includes(null, 'a string');
+});
+assert.sameValue(closed, true, 'iterator closed when skippedElements validation produces a TypeError');

test/built-ins/Iterator/prototype/includes/basic-match-and-miss.js

@@ -0,0 +1,22 @@
+// Copyright (C) 2026 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iterator.prototype.includes
+description: >
+  Basic positive and negative matches
+features: [iterator-includes]
+---*/
+
+let arr = [3, 6, 9];
+
+assert.sameValue(arr.values().includes(0), false);
+assert.sameValue(arr.values().includes(1), false);
+assert.sameValue(arr.values().includes(2), false);
+assert.sameValue(arr.values().includes(3), true);
+assert.sameValue(arr.values().includes(4), false);
+assert.sameValue(arr.values().includes(5), false);
+assert.sameValue(arr.values().includes(6), true);
+assert.sameValue(arr.values().includes(7), false);
+assert.sameValue(arr.values().includes(8), false);
+assert.sameValue(arr.values().includes(9), true);
+assert.sameValue(arr.values().includes(10), false);

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

@@ -0,0 +1,16 @@
+// Copyright (C) 2026 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iterator.prototype.includes
+description: >
+  Iterator.prototype.includes is callable
+features: [iterator-includes]
+---*/
+
+function* g() {
+  yield 0;
+}
+
+Iterator.prototype.includes.call(g(), 0);
+
+g().includes(0);

test/built-ins/Iterator/prototype/includes/closes-on-match.js

@@ -0,0 +1,25 @@
+// Copyright (C) 2026 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iterator.prototype.includes
+description: >
+  Iterator.prototype.includes closes the iterator after a successful match
+features: [iterator-includes]
+---*/
+
+let closed = false;
+let i = 0;
+let iter = {
+  __proto__: Iterator.prototype,
+  next() {
+    ++i;
+    return { done: false, value: i };
+  },
+  return() {
+    closed = true;
+    return {};
+  },
+};
+
+assert.sameValue(iter.includes(5), true);
+assert.sameValue(closed, true);

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

@@ -0,0 +1,29 @@
+// Copyright (C) 2026 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iterator.prototype.includes
+description: >
+  Exhausting the iterator without finding a match does not call return
+features: [iterator-includes]
+---*/
+
+let index = 0;
+let returnCalls = 0;
+
+let iterator = {
+  __proto__: Iterator.prototype,
+  next() {
+    ++index;
+    if (index <= 3) {
+      return { done: false, value: index };
+    }
+    return { done: true, value: undefined };
+  },
+  return() {
+    ++returnCalls;
+    return {};
+  },
+};
+
+assert.sameValue(iterator.includes(99), false);
+assert.sameValue(returnCalls, 0);

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

@@ -0,0 +1,29 @@
+// Copyright (C) 2026 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iterator.prototype.includes
+description: >
+  Gets the next method from the iterator only once
+features: [iterator-includes]
+---*/
+
+let nextGets = 0;
+
+class TestIterator extends Iterator {
+  get next() {
+    ++nextGets;
+    let counter = 5;
+    return function() {
+      if (counter < 0) {
+        return { done: true, value: undefined };
+      }
+      return { done: false, value: --counter };
+    };
+  }
+}
+
+let iterator = new TestIterator();
+
+assert.sameValue(nextGets, 0);
+assert.sameValue(iterator.includes(3), true);
+assert.sameValue(nextGets, 1);

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

@@ -0,0 +1,20 @@
+// Copyright (C) 2026 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iterator.prototype.includes
+description: >
+  Iterator has throwing next getter
+features: [iterator-includes]
+---*/
+
+class IteratorThrows extends Iterator {
+  get next() {
+    throw new Test262Error();
+  }
+}
+
+let iterator = new IteratorThrows();
+
+assert.throws(Test262Error, function() {
+  iterator.includes(0);
+});

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

@@ -0,0 +1,27 @@
+// Copyright (C) 2026 Michael Ficarra. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iterator.prototype.includes
+description: >
+  Iterator has throwing return getter
+features: [iterator-includes]
+---*/
+
+class IteratorThrows extends Iterator {
+  next() {
+    return {
+      done: false,
+      value: 0,
+    };
+  }
+
+  get return() {
+    throw new Test262Error();
+  }
+}
+
+let iterator = new IteratorThrows();
+
+assert.throws(Test262Error, function() {
+  iterator.includes(0);
+});