1 files changed, 122 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/basic/object-assign-plain.js b/js/src/jit-test/tests/basic/object-assign-plain.js
new file mode 100644
index 0000000000..0476eb8c09
--- /dev/null
+++ b/js/src/jit-test/tests/basic/object-assign-plain.js
@@ -0,0 +1,122 @@
+// Tests for Object.assign's fast path for plain objects.
+
+load(libdir + "asserts.js");
+
+function testProtoSetter() {
+    var from = Object.create(null);
+    from.__proto__ = {};
+    assertEq(Object.getPrototypeOf(from), null);
+
+    var to = Object.assign({}, from);
+    assertEq(Object.getPrototypeOf(to), from.__proto__);
+    assertEq(Object.getOwnPropertyNames(to).length, 0);
+}
+testProtoSetter();
+
+function testProtoDataProp() {
+    var to = Object.create(null);
+    to.__proto__ = 1;
+    var from = Object.create(null);
+    from.__proto__ = 2;
+    Object.assign(to, from);
+    assertEq(Object.getPrototypeOf(to), null);
+    assertEq(to.__proto__, 2);
+}
+testProtoDataProp();
+
+function testNonExtensible() {
+    var to = Object.preventExtensions({x: 1});
+    Object.assign(to, {x: 2});
+    assertEq(to.x, 2);
+    assertThrowsInstanceOf(() => Object.assign(to, {x: 3, y: 4}), TypeError);
+    assertEq(to.x, 3);
+    assertEq("y" in to, false);
+}
+testNonExtensible();
+
+function testNonExtensibleNoProps() {
+    var to = Object.preventExtensions({});
+    Object.assign(to, {}); // No exception.
+}
+testNonExtensibleNoProps();
+
+function testDenseElements() {
+    var to = Object.assign({}, {0: 1, 1: 2});
+    assertEq(to[0], 1);
+    assertEq(to[1], 2);
+}
+testDenseElements();
+
+function testNonWritableOnProto() {
+    var proto = {};
+    Object.defineProperty(proto, "x", {value: 1, enumerable: true, configurable: true});
+    var to = Object.create(proto);
+    assertThrowsInstanceOf(() => Object.assign(to, {x: 2}), TypeError);
+    assertEq(to.x, 1);
+    assertEq(Object.getOwnPropertyNames(to).length, 0);
+}
+testNonWritableOnProto();
+
+function testAccessorOnProto() {
+    var setterVal;
+    var proto = {set a(v) { setterVal = v; }};
+    var to = Object.assign(Object.create(proto), {a: 9});
+    assertEq(setterVal, 9);
+    assertEq(Object.getOwnPropertyNames(to).length, 0);
+}
+testAccessorOnProto();
+
+function testSetAndAdd() {
+    var to = Object.assign({x: 1, y: 2}, {x: 3, y: 4, z: 5});
+    assertEq(to.x, 3);
+    assertEq(to.y, 4);
+    assertEq(to.z, 5);
+}
+testSetAndAdd();
+
+function testNonConfigurableFrom() {
+    var from = {};
+    Object.defineProperty(from, "x", {value: 1, enumerable: true, writable: true});
+    var to = Object.assign({}, from);
+    assertEq(to.x, 1);
+    assertEq(Object.getOwnPropertyDescriptor(to, "x").configurable, true);
+}
+testNonConfigurableFrom();
+
+function testNonEnumerableFrom() {
+    var from = {};
+    Object.defineProperty(from, "x", {value: 1, configurable: true, writable: true});
+    var to = Object.assign({}, from);
+    assertEq(Object.getOwnPropertyNames(to).length, 0);
+    assertEq(to.x, undefined);
+}
+testNonEnumerableFrom();
+
+function testNonWritableFrom() {
+    var from = {};
+    Object.defineProperty(from, "x", {value: 1, configurable: true, enumerable: true});
+    var to = Object.assign({}, from);
+    assertEq(to.x, 1);
+    assertEq(Object.getOwnPropertyDescriptor(to, "x").writable, true);
+}
+testNonWritableFrom();
+
+function testFrozenProto() {
+    var proto = Object.freeze({x: 1});
+    var target = Object.create(proto);
+    Object.assign(target, {foo: 1});
+    assertEq(target.foo, 1);
+    assertThrowsInstanceOf(() => Object.assign(target, {x: 2}), TypeError);
+    assertEq(target.x, 1);
+}
+testFrozenProto();
+
+function testReuseShape() {
+    var from = {};
+    from.x = 1;
+    from.y = 2;
+    var to = Object.assign({}, from);
+    assertEq(to.x, 1);
+    assertEq(to.y, 2);
+}
+testReuseShape();