diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/collections/Array-build-basic.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/collections/Array-build-basic.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,22 @@
+// Array.build basics
+
+if (getBuildConfiguration().parallelJS) {
+  load(libdir + "asserts.js");
+  load(libdir + "eqArrayHelper.js");
+
+  function myBuild(l, f) {
+    var a = [];
+    for (var i = 0; i < l; i++)
+      a.push(f(i));
+    return a;
+  }
+
+  // Test that build returns an identical, but new array.
+  var a1 = [];
+  for (var i = 0; i < 100; i++)
+    a1[i] = Math.random();
+  var a2 = Array.build(a1.length, (i) => a1[i]);
+
+  assertEq(a1 === a2, false);
+  assertEqArray(a2, a1);
+}