1 files changed, 56 insertions, 0 deletions
diff --git a/js/src/tests/ecma_6/Reflect/preventExtensions.js b/js/src/tests/ecma_6/Reflect/preventExtensions.js
new file mode 100644
index 000000000..63ca2545b
--- /dev/null
+++ b/js/src/tests/ecma_6/Reflect/preventExtensions.js
@@ -0,0 +1,56 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/licenses/publicdomain/ */
+
+// Reflect.preventExtensions is the same as Object.preventExtensions, except
+// for the return value and the behavior in error cases.
+
+var someObjects = [
+    {},
+    new Int32Array(7),
+    Object(Symbol("table")),
+    new Proxy({}, {})
+];
+
+for (var obj of someObjects) {
+    assertEq(Reflect.preventExtensions(obj), true);
+    // [[PreventExtensions]] on an already-inextensible object is a no-op.
+    assertEq(Reflect.preventExtensions(obj), true);
+}
+
+// Error cases.
+assertThrowsInstanceOf(() => Reflect.isExtensible(), TypeError);
+for (var value of [undefined, null, true, 1, NaN, "Phaedo", Symbol("good")]) {
+    assertThrowsInstanceOf(() => Reflect.isExtensible(value), TypeError);
+}
+
+// A proxy's preventExtensions handler can return false without doing anything.
+obj = {};
+var proxy = new Proxy(obj, {
+    preventExtensions() { return false; }
+});
+assertEq(Reflect.preventExtensions(proxy), false);
+assertEq(Reflect.isExtensible(obj), true);
+assertEq(Reflect.isExtensible(proxy), true);
+
+// If a proxy's preventExtensions handler throws, the exception is propagated.
+obj = {};
+proxy = new Proxy(obj, {
+    preventExtensions() { throw "fit"; }
+});
+assertThrowsValue(() => Reflect.preventExtensions(proxy), "fit");
+assertEq(Reflect.isExtensible(obj), true);
+assertEq(Reflect.isExtensible(proxy), true);
+
+// If a proxy's preventExtensions handler returns true while leaving the target
+// extensible, that's a TypeError.
+obj = {};
+proxy = new Proxy(obj, {
+    preventExtensions() { return true; }
+});
+assertThrowsInstanceOf(() => Reflect.preventExtensions(proxy), TypeError);
+assertEq(Reflect.isExtensible(obj), true);
+assertEq(Reflect.isExtensible(proxy), true);
+
+// For more Reflect.preventExtensions tests, see target.js.
+
+reportCompare(0, 0);