Add tests for Joint Iteration proposal + split tests

features.txt

@@ -100,6 +100,10 @@ canonical-tz
 # https://github.com/tc39/proposal-upsert
 upsert
 
+# Joint Iteration
+# https://github.com/tc39/proposal-joint-iteration
+joint-iteration
+
 ## Standard language features
 #
 # Language features that have been included in a published version of the

harness/iteratorZipUtils.js

@@ -0,0 +1,223 @@
+// Copyright (C) 2025 André Bargull.  All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: |
+    Utility functions for testing Iterator.prototype.zip and Iterator.prototype.zipKeyed. Requires inclusion of propertyHelper.js.
+defines:
+  - forEachSequenceCombination
+  - forEachSequenceCombinationKeyed
+  - assertZipped
+  - assertZippedKeyed
+  - assertIteratorResult
+  - assertIsPackedArray
+---*/
+
+// Assert |result| is an object created by CreateIteratorResultObject.
+function assertIteratorResult(result, value, done, label) {
+  assert.sameValue(
+    Object.getPrototypeOf(result),
+    Object.prototype,
+    label + ": [[Prototype]] of iterator result is Object.prototype"
+  );
+
+  assert(Object.isExtensible(result), label + ": iterator result is extensible");
+
+  var ownKeys = Reflect.ownKeys(result);
+  assert.compareArray(ownKeys, ["value", "done"], label + ": iterator result properties");
+
+  verifyProperty(result, "value", {
+    value: value,
+    writable: true,
+    enumerable: true,
+    configurable: true,
+  });
+
+  verifyProperty(result, "done", {
+    value: done,
+    writable: true,
+    enumerable: true,
+    configurable: true,
+  });
+}
+
+// Assert |array| is a packed array with default property attributes.
+function assertIsPackedArray(array, label) {
+  assert(Array.isArray(array), label + ": array is an array exotic object");
+
+  assert.sameValue(
+    Object.getPrototypeOf(array),
+    Array.prototype,
+    label + ": [[Prototype]] of array is Array.prototype"
+  );
+
+  assert(Object.isExtensible(array), label + ": array is extensible");
+
+  // Ensure "length" property has its default property attributes.
+  verifyProperty(array, "length", {
+    writable: true,
+    enumerable: false,
+    configurable: false,
+  });
+
+  // Ensure no holes and all elements have the default property attributes.
+  for (var i = 0; i < array.length; i++) {
+    verifyProperty(array, i, {
+      writable: true,
+      enumerable: true,
+      configurable: true,
+    });
+  }
+}
+
+// Assert |array| is an extensible null-prototype object with default property attributes.
+function _assertIsNullProtoMutableObject(object, label) {
+  assert.sameValue(
+    Object.getPrototypeOf(object),
+    null,
+    label + ": [[Prototype]] of object is null"
+  );
+
+  assert(Object.isExtensible(object), label + ": object is extensible");
+
+  // Ensure all properties have the default property attributes.
+  var keys = Object.getOwnPropertyNames(object);
+  for (var i = 0; i < keys.length; i++) {
+    verifyProperty(object, keys[i], {
+      writable: true,
+      enumerable: true,
+      configurable: true,
+    });
+  }
+}
+
+// Assert that the `zipped` iterator results as for Iterator.zip for the first `count` elements.
+// Assumes inputs is an array of arrays of length >= count.
+// Advances `zipped` by `count` steps.
+function assertZipped(zipped, inputs, count, label) {
+  // Last returned elements array.
+  var last = null;
+
+  for (var i = 0; i < count; i++) {
+    var itemLabel = label + ", step " + i;
+
+    var result = zipped.next();
+    var value = result.value;
+
+    // Test IteratorResult structure.
+    assertIteratorResult(result, value, false, itemLabel);
+
+    // Ensure value is a new array.
+    assert.notSameValue(value, last, itemLabel + ": returns a new array");
+    last = value;
+
+    // Ensure all array elements have the expected value.
+    var expected = inputs.map(function (array) {
+      return array[i];
+    });
+    assert.compareArray(value, expected, itemLabel + ": values");
+
+    // Ensure value is a packed array with default data properties.
+    //
+    // This operation is destructive, so it has to happen last.
+    assertIsPackedArray(value, itemLabel);
+  }
+}
+
+// Assert that the `zipped` iterator results as for Iterator.zipKeyed for the first `count` elements.
+// Assumes inputs is an object whose values are arrays of length >= count.
+// Advances `zipped` by `count` steps.
+function assertZippedKeyed(zipped, inputs, count, label) {
+  // Last returned elements array.
+  var last = null;
+
+  var expectedKeys = Object.keys(inputs);
+
+  for (var i = 0; i < count; i++) {
+    var itemLabel = label + ", step " + i;
+
+    var result = zipped.next();
+    var value = result.value;
+
+    // Test IteratorResult structure.
+    assertIteratorResult(result, value, false, itemLabel);
+
+    // Ensure resulting object is a new object.
+    assert.notSameValue(value, last, itemLabel + ": returns a new object");
+    last = value;
+
+    // Ensure resulting object has the expected keys and values.
+    assert.compareArray(Reflect.ownKeys(value), expectedKeys, itemLabel + ": result object keys");
+
+    var expectedValues = Object.values(inputs).map(function (array) {
+      return array[i];
+    });
+    assert.compareArray(Object.values(value), expectedValues, itemLabel + ": result object values");
+
+    // Ensure resulting object is a null-prototype mutable object with default data properties.
+    //
+    // This operation is destructive, so it has to happen last.
+    _assertIsNullProtoMutableObject(value, itemLabel);
+  }
+}
+
+function forEachSequenceCombinationKeyed(callback) {
+  return forEachSequenceCombination(function(inputs, inputsLabel, min, max) {
+    var object = {};
+    for (var i = 0; i < inputs.length; ++i) {
+      object["prop_" + i] = inputs[i];
+    }
+    inputsLabel = "inputs = " + JSON.stringify(object);
+    callback(object, inputsLabel, min, max);
+  });
+}
+
+function forEachSequenceCombination(callback) {
+  function test(inputs) {
+    if (inputs.length === 0) {
+      callback(inputs, "inputs = []", 0, 0);
+      return;
+    }
+
+    var lengths = inputs.map(function(array) {
+      return array.length;
+    });
+
+    var min = Math.min.apply(null, lengths);
+    var max = Math.max.apply(null, lengths);
+
+    var inputsLabel = "inputs = " + JSON.stringify(inputs);
+
+    callback(inputs, inputsLabel, min, max);
+  }
+
+  // Yield all prefixes of the string |s|.
+  function* prefixes(s) {
+    for (var i = 0; i <= s.length; ++i) {
+      yield s.slice(0, i);
+    }
+  }
+
+  // Zip an empty iterable.
+  test([]);
+
+  // Zip a single iterator.
+  for (var prefix of prefixes("abcd")) {
+    test([prefix.split("")]);
+  }
+
+  // Zip two iterators.
+  for (var prefix1 of prefixes("abcd")) {
+    for (var prefix2 of prefixes("efgh")) {
+      test([prefix1.split(""), prefix2.split("")]);
+    }
+  }
+
+  // Zip three iterators.
+  for (var prefix1 of prefixes("abcd")) {
+    for (var prefix2 of prefixes("efgh")) {
+      for (var prefix3 of prefixes("ijkl")) {
+        test([prefix1.split(""), prefix2.split(""), prefix3.split("")]);
+      }
+    }
+  }
+}

test/built-ins/Iterator/zip/basic-longest.js

@@ -0,0 +1,85 @@
+// Copyright (C) 2025 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-iterator.zip
+description: >
+  Basic Iterator.zip test with "longest" mode.
+includes: [compareArray.js, propertyHelper.js, iteratorZipUtils.js]
+features: [joint-iteration]
+---*/
+
+function testSequence(inputs, inputsLabel, minLength, maxLength) {
+  function test(options, optionsLabel, getPaddingForInput) {
+    var label = optionsLabel + ", " + inputsLabel;
+    var it = Iterator.zip(inputs, options);
+    assertZipped(it, inputs, minLength, label);
+
+    for (var i = minLength; i < maxLength; i++) {
+      var itemLabel = label + ", step " + i;
+
+      var result = it.next();
+      var value = result.value;
+
+      // Test IteratorResult structure.
+      assertIteratorResult(result, value, false, itemLabel);
+
+      var expected = inputs.map(function (input, j) {
+        return i < input.length ? input[i] : getPaddingForInput(j);
+      });
+      assert.compareArray(value, expected, itemLabel + ": values");
+    }
+    assertIteratorResult(it.next(), undefined, true, label + ": after completion");
+  }
+
+  test(
+    { mode: "longest" },
+    "options = { mode: 'longest' }",
+    function () {
+      return undefined;
+    },
+  );
+
+  test(
+    { mode: "longest", padding: [] },
+    "options = { mode: 'longest', padding: [] }",
+    function () {
+      return undefined;
+    },
+  );
+
+  test(
+    { mode: "longest", padding: ["pad"] },
+    "options = { mode: 'longest', padding: ['pad'] }",
+    function (idx) {
+      return idx === 0 ? "pad" : undefined;
+    },
+  );
+
+  test(
+    { mode: "longest", padding: Array(inputs.length).fill("pad") },
+    "options = { mode: 'longest', padding: ['pad', 'pad', ..., 'pad'] }",
+    function (idx) {
+      return "pad";
+    },
+  );
+
+  // Yield an infinite amount of numbers.
+  var numbers = {
+    *[Symbol.iterator]() {
+      var i = 0;
+      while (true) {
+        yield 100 + i++;
+      }
+    }
+  };
+  test(
+    { mode: "longest", padding: numbers },
+    "options = { mode: 'longest', padding: numbers }",
+    function (idx) {
+      return 100 + idx;
+    },
+  );
+}
+
+forEachSequenceCombination(testSequence);

test/built-ins/Iterator/zip/basic-shortest.js

@@ -0,0 +1,29 @@
+// Copyright (C) 2025 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-iterator.zip
+description: >
+  Basic Iterator.zip test with "shortest" mode.
+includes: [compareArray.js, propertyHelper.js, iteratorZipUtils.js]
+features: [joint-iteration]
+---*/
+
+function testSequence(inputs, inputsLabel, minLength, maxLength) {
+  function test(options, optionsLabel) {
+    var label = optionsLabel + ", " + inputsLabel;
+    var it = Iterator.zip(inputs, options);
+    assertZipped(it, inputs, minLength, label);
+
+    // Iterator is closed after `minLength` items.
+    assertIteratorResult(it.next(), undefined, true, label + ": after completion");
+  }
+
+  test(undefined, "options = undefined");
+
+  test({}, "options = {}");
+
+  test({ mode: "shortest" }, "options = { mode: 'shortest' }");
+}
+
+forEachSequenceCombination(testSequence);

test/built-ins/Iterator/zip/basic-strict.js

@@ -0,0 +1,30 @@
+// Copyright (C) 2025 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-iterator.zip
+description: >
+  Basic Iterator.zip test with "strict" mode.
+includes: [compareArray.js, propertyHelper.js, iteratorZipUtils.js]
+features: [joint-iteration]
+---*/
+
+function testSequence(inputs, inputsLabel, minLength, maxLength) {
+  function test(options, optionsLabel) {
+    var label = optionsLabel + ", " + inputsLabel;
+    var it = Iterator.zip(inputs, options);
+    assertZipped(it, inputs, minLength, label);
+
+    if (minLength === maxLength) {
+      assertIteratorResult(it.next(), undefined, true, label + ": after completion");
+    } else {
+      assert.throws(TypeError, function() {
+        it.next();
+      }, label + " should throw after " + minLength + " items.");
+    }
+  }
+
+  test({ mode: "strict" }, "options = { mode: 'strict' }");
+}
+
+forEachSequenceCombination(testSequence);

test/built-ins/Iterator/zip/is-function.js

@@ -0,0 +1,15 @@
+// Copyright (C) 2025 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-iterator.zip
+description: >
+  Iterator.zip is a built-in function
+features: [joint-iteration]
+---*/
+
+assert.sameValue(
+  typeof Iterator.zip,
+  "function",
+  "The value of `typeof Iterator.zip` is 'function'"
+);