test: Add more Array.from tests for array-like. Closes gh-3336

test/built-ins/Array/from/array-like-has-length-but-no-indexes-with-values.js

@@ -0,0 +1,39 @@
+// Copyright (c) 2021 Rick Waldron.  All rights reserved.
+// This code is governed by the license found in the LICENSE file.
+
+/*---
+esid: sec-array.from
+description: >
+    Creates an array with length that is equal to the value of the
+    length property of the given array-like, regardless of
+    the presence of corresponding indices and values.
+info: |
+    Array.from ( items [ , mapfn [ , thisArg ] ] )
+
+    7. Let arrayLike be ! ToObject(items).
+    8. Let len be ? LengthOfArrayLike(arrayLike).
+    9. If IsConstructor(C) is true, then
+      a. Let A be ? Construct(C, « 𝔽(len) »).
+    10. Else,
+      a. Let A be ? ArrayCreate(len).
+
+includes: [compareArray.js]
+---*/
+
+const length = 5;
+
+const newlyCreatedArray = Array.from({ length });
+assert.sameValue(
+  newlyCreatedArray.length,
+  length,
+  "The newly created array's length is equal to the value of the length property for the provided array like object"
+);
+assert.compareArray(newlyCreatedArray, [undefined, undefined, undefined, undefined, undefined]);
+
+const newlyCreatedAndMappedArray = Array.from({ length }).map(x => 1);
+assert.sameValue(
+  newlyCreatedAndMappedArray.length,
+  length,
+  "The newly created and mapped array's length is equal to the value of the length property for the provided array like object"
+);
+assert.compareArray(newlyCreatedAndMappedArray, [1, 1, 1, 1, 1]);