Bug 2025779 - Import Iterator Includes tests; r=arai

These are from tc39/test262#5031 which is
currently under review. Once the tests land upstream, these can be
removed. This will be handled as part of shipping the feature when
it reaches Stage 3.

Differential Revision: https://phabricator.services.mozilla.com/D295351

Author: dminor

js/src/tests/test262/prs/5031/browser.js

@@ -0,0 +1,70 @@
+// |reftest| shell-option(--enable-iterator-includes) skip-if(!Iterator.prototype.includes||!xulRuntime.shell) -- iterator-includes is not enabled unconditionally, requires shell-options
+// 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']);
+
+reportCompare(0, 0);

js/src/tests/test262/prs/5031/built-ins/Iterator/browser.js

@@ -0,0 +1,34 @@
+// |reftest| shell-option(--enable-iterator-includes) skip-if(!Iterator.prototype.includes||!xulRuntime.shell) -- iterator-includes is not enabled unconditionally, requires shell-options
+// 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');
+
+reportCompare(0, 0);

js/src/tests/test262/prs/5031/built-ins/Iterator/prototype/browser.js

@@ -0,0 +1,25 @@
+// |reftest| shell-option(--enable-iterator-includes) skip-if(!Iterator.prototype.includes||!xulRuntime.shell) -- iterator-includes is not enabled unconditionally, requires shell-options
+// 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);
+
+reportCompare(0, 0);

js/src/tests/test262/prs/5031/built-ins/Iterator/prototype/includes/argument-effect-order.js

@@ -0,0 +1,19 @@
+// |reftest| shell-option(--enable-iterator-includes) skip-if(!Iterator.prototype.includes||!xulRuntime.shell) -- iterator-includes is not enabled unconditionally, requires shell-options
+// 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);
+
+reportCompare(0, 0);

js/src/tests/test262/prs/5031/built-ins/Iterator/prototype/includes/argument-validation-failure-closes-underlying.js

@@ -0,0 +1,28 @@
+// |reftest| shell-option(--enable-iterator-includes) skip-if(!Iterator.prototype.includes||!xulRuntime.shell) -- iterator-includes is not enabled unconditionally, requires shell-options
+// 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);
+
+reportCompare(0, 0);

js/src/tests/test262/prs/5031/built-ins/Iterator/prototype/includes/basic-match-and-miss.js

@@ -0,0 +1,32 @@
+// |reftest| shell-option(--enable-iterator-includes) skip-if(!Iterator.prototype.includes||!xulRuntime.shell) -- iterator-includes is not enabled unconditionally, requires shell-options
+// 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);
+
+reportCompare(0, 0);