[modules] Implement namespace imports.

test/mjsunit/modules-namespace1.js

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// MODULE
+
+let ja = 42;
+export {ja as yo};
+export const bla = "blaa";
+export {foo as foo_again};
+// See further below for the actual star import that declares "foo".
+
+// The object itself.
+assertEquals("object", typeof foo);
+assertThrows(() => foo = 666, TypeError);
+assertFalse(Reflect.isExtensible(foo));
+assertTrue(Reflect.preventExtensions(foo));
+assertThrows(() => Reflect.apply(foo, {}, []));
+assertThrows(() => Reflect.construct(foo, {}, []));
+assertSame(null, Reflect.getPrototypeOf(foo));
+// TODO(neis): The next one should be False.
+assertTrue(Reflect.setPrototypeOf(foo, null));
+assertFalse(Reflect.setPrototypeOf(foo, {}));
+assertSame(null, Reflect.getPrototypeOf(foo));
+// TODO(neis): The next one should include @@iterator at the end.
+assertEquals(
+    ["bla", "foo_again", "yo", Symbol.toStringTag],
+    Reflect.ownKeys(foo));
+
+// Its "yo" property.
+assertEquals(
+    {value: 42, enumerable: true, configurable: false, writable: true},
+    Reflect.getOwnPropertyDescriptor(foo, "yo"));
+assertFalse(Reflect.deleteProperty(foo, "yo"));
+assertTrue(Reflect.has(foo, "yo"));
+// TODO(neis): The next three should be False.
+assertTrue(Reflect.set(foo, "yo", true));
+assertTrue(Reflect.defineProperty(foo, "yo",
+    Reflect.getOwnPropertyDescriptor(foo, "yo")));
+assertTrue(Reflect.defineProperty(foo, "yo", {}));
+assertFalse(Reflect.defineProperty(foo, "yo", {get() {return 1}}));
+assertEquals(42, Reflect.get(foo, "yo"));
+assertEquals(43, (ja++, foo.yo));
+
+// Its "foo_again" property.
+assertSame(foo, foo.foo_again);
+
+// Its @@toStringTag property.
+assertTrue(Reflect.has(foo, Symbol.toStringTag));
+assertEquals("string", typeof Reflect.get(foo, Symbol.toStringTag));
+assertEquals(
+    {value: "Module", configurable: true, writable: false, enumerable: false},
+    Reflect.getOwnPropertyDescriptor(foo, Symbol.toStringTag));
+
+// TODO(neis): Its @@iterator property.
+// assertTrue(Reflect.has(foo, Symbol.iterator));
+// assertEquals("function", typeof Reflect.get(foo, Symbol.iterator));
+// assertEquals(["bla", "yo"], [...foo]);
+// assertThrows(() => (42, foo[Symbol.iterator])(), TypeError);
+// assertSame(foo[Symbol.iterator]().__proto__,
+//     ([][Symbol.iterator]()).__proto__.__proto__);
+
+// TODO(neis): Clarify spec w.r.t. other symbols.
+
+// Nonexistant properties.
+let nonexistant = ["gaga", 123, Symbol('')];
+for (let key of nonexistant) {
+  assertSame(undefined, Reflect.getOwnPropertyDescriptor(foo, key));
+  assertTrue(Reflect.deleteProperty(foo, key));
+  assertFalse(Reflect.set(foo, key, true));
+  assertSame(undefined, Reflect.get(foo, key));
+  assertFalse(Reflect.defineProperty(foo, key, {get() {return 1}}));
+  assertFalse(Reflect.has(foo, key));
+}
+
+// The actual star import that we are testing. Namespace imports are
+// initialized before evaluation
+import * as foo from "modules-namespace1.js";
+
+// There can be only one namespace object.
+import * as bar from "modules-namespace1.js";
+assertSame(foo, bar);