1 files changed, 36 insertions, 0 deletions
diff --git a/js/src/tests/test262/harness/compare-array-arraylike.js b/js/src/tests/test262/harness/compare-array-arraylike.js
new file mode 100644
index 0000000000..6f1ea8242b
--- /dev/null
+++ b/js/src/tests/test262/harness/compare-array-arraylike.js
@@ -0,0 +1,36 @@
+// Copyright (C) 2021 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: >
+    Accepts spreadable arguments
+includes: [compareArray.js]
+---*/
+
+function checkFormatOfAssertionMessage(func, errorMessage) {
+  var caught = false;
+  try {
+      func();
+  } catch (error) {
+      caught = true;
+      assert.sameValue(error.constructor, Test262Error);
+      assert.sameValue(error.message, errorMessage);
+  }
+
+  assert(caught, `Expected ${func} to throw, but it didn't.`);
+}
+
+const fixture = { length: 3, 0: 0, 1: 'a', 2: undefined};
+
+assert.compareArray(fixture, [0, 'a', undefined]);
+assert.compareArray([0, 'a', undefined], fixture);
+
+checkFormatOfAssertionMessage(() => {
+  assert.compareArray(fixture, [], 'fixture and []');
+}, 'Expected [0, a, undefined] and [] to have the same contents. fixture and []');
+
+checkFormatOfAssertionMessage(() => {
+  assert.compareArray([], fixture, '[] and fixture');
+}, 'Expected [] and [0, a, undefined] to have the same contents. [] and fixture');
+
+reportCompare(0, 0);