1 files changed, 47 insertions, 0 deletions
diff --git a/js/src/tests/non262/TypedArray/at.js b/js/src/tests/non262/TypedArray/at.js
new file mode 100644
index 0000000000..bab5dc8ff2
--- /dev/null
+++ b/js/src/tests/non262/TypedArray/at.js
@@ -0,0 +1,47 @@
+for (var constructor of anyTypedArrayConstructors) {
+    assertEq(constructor.prototype.at.length, 1);
+
+    assertEq(new constructor([0]).at(0), 0);
+    assertEq(new constructor([0]).at(-1), 0);
+
+    assertEq(new constructor([]).at(0), undefined);
+    assertEq(new constructor([]).at(-1), undefined);
+    assertEq(new constructor([]).at(1), undefined);
+
+    assertEq(new constructor([0, 1]).at(0), 0);
+    assertEq(new constructor([0, 1]).at(1), 1);
+    assertEq(new constructor([0, 1]).at(-2), 0);
+    assertEq(new constructor([0, 1]).at(-1), 1);
+
+    assertEq(new constructor([0, 1]).at(2), undefined);
+    assertEq(new constructor([0, 1]).at(-3), undefined);
+    assertEq(new constructor([0, 1]).at(-4), undefined);
+    assertEq(new constructor([0, 1]).at(Infinity), undefined);
+    assertEq(new constructor([0, 1]).at(-Infinity), undefined);
+    assertEq(new constructor([0, 1]).at(NaN), 0); // ToInteger(NaN) = 0
+
+    // Called from other globals.
+    if (typeof newGlobal === "function") {
+        var at = newGlobal()[constructor.name].prototype.at;
+        assertEq(at.call(new constructor([1, 2, 3]), 2), 3);
+    }
+
+    // Throws if `this` isn't a TypedArray.
+    var invalidReceivers = [undefined, null, 1, false, "", Symbol(), [], {}, /./,
+                            new Proxy(new constructor(), {})];
+    invalidReceivers.forEach(invalidReceiver => {
+        assertThrowsInstanceOf(() => {
+            constructor.prototype.at.call(invalidReceiver);
+        }, TypeError, "Assert that 'at' fails if this value is not a TypedArray");
+    });
+
+    // Test that the length getter is never called.
+    assertEq(Object.defineProperty(new constructor([1, 2, 3]), "length", {
+        get() {
+            throw new Error("length accessor called");
+        }
+    }).at(1), 2);
+}
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);