Adding tests of Object/Array.prototype.toString on proxy objects.

Author: iamstolis

graal-js/src/com.oracle.truffle.js.test/js/GR-32016.js

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2021, 2021, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * Licensed under the Universal Permissive License v 1.0 as shown at http://oss.oracle.com/licenses/upl.
+ */
+
+/**
+ * Tests of Object/Array.prototype.toString on proxy objects.
+ */
+
+load('assert.js');
+
+// Ensure that Array.prototype.toString invokes Object.prototype.toString
+delete Array.prototype.join;
+
+[Object.prototype.toString, Array.prototype.toString].forEach(function (testedFunction) {
+    // Proxy does not inherit [[ParameterMap]], [[ErrorData]], [[BooleanData]],
+    // [[NumberData]], [[StringData]], [[DateValue]] and [[RegExpMatcher]] internal slots
+    var argumentsObject = (function() { return arguments; })();
+    assertSame('[object Object]', testedFunction.call(new Proxy(argumentsObject, {})));
+    assertSame('[object Object]', testedFunction.call(new Proxy(new Error(), {})));
+    assertSame('[object Object]', testedFunction.call(new Proxy(Object(true), {})));
+    assertSame('[object Object]', testedFunction.call(new Proxy(Object(42), {})));
+    assertSame('[object Object]', testedFunction.call(new Proxy(Object('foo'), {})));
+    assertSame('[object Object]', testedFunction.call(new Proxy(new Date(), {})));
+    assertSame('[object Object]', testedFunction.call(new Proxy(/a/, {})));
+
+    // Proxy inherits [[Call]] internal slot
+    assertSame('[object Function]', testedFunction.call(new Proxy(function() {}, {})));
+
+    // There is an explicit handling of array Proxy targets in Object.prototype.toString
+    assertSame('[object Array]', testedFunction.call(new Proxy([], {})));
+    // revoked
+    var revocable = Proxy.revocable([], {});
+    revocable.revoke();
+    assertThrows(function() {
+        testedFunction.call(revocable.proxy);
+    }, TypeError);
+    // revoked too late (after builtinTag was determined)
+    revocable = Proxy.revocable([], {
+        get: function (target, key, receiver) {
+            if (key === Symbol.toStringTag) {
+                revocable.revoke();
+                return undefined;
+            } else {
+                return Reflect.get(target, key, receiver);
+            }
+        },
+    });
+    assertSame('[object Array]', testedFunction.call(revocable.proxy));    
+});