diff --git a/test/built-ins/Proxy/isExtensible/call-parameters.js b/test/built-ins/Proxy/isExtensible/call-parameters.js
new file mode 100644
index 0000000000000000000000000000000000000000..e2e5db3cc3d9a2c8cda8e76582a3b2db450329f6
--- /dev/null
+++ b/test/built-ins/Proxy/isExtensible/call-parameters.js
@@ -0,0 +1,31 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 9.5.3
+description: >
+    The trap is called with handler on its context and the target object as the
+    first parabeter
+info: >
+    [[IsExtensible]] ( )
+
+    ...
+    8. Let booleanTrapResult be ToBoolean(Call(trap, handler, «target»)).
+    ...
+
+---*/
+
+var _target, _handler;
+var target = {};
+var handler = {
+    isExtensible: function(t) {
+        _handler = this;
+        _target = t;
+        return Object.isExtensible(t);
+    }
+}
+var p = new Proxy(target, handler);
+
+Object.isExtensible(p);
+
+assert.sameValue(_handler, handler);
+assert.sameValue(_target, target);
diff --git a/test/built-ins/Proxy/isExtensible/null-handler.js b/test/built-ins/Proxy/isExtensible/null-handler.js
new file mode 100644
index 0000000000000000000000000000000000000000..d8d14bf7c86dca4ac46307628a1ee1537e93700c
--- /dev/null
+++ b/test/built-ins/Proxy/isExtensible/null-handler.js
@@ -0,0 +1,15 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 9.5.3
+description: >
+    Throws a TypeError exception if handler is null
+---*/
+
+var p = Proxy.revocable({}, {});
+
+p.revoke();
+
+assert.throws(TypeError, function() {
+    Object.isExtensible(p.proxy);
+});
diff --git a/test/built-ins/Proxy/isExtensible/return-is-abrupt.js b/test/built-ins/Proxy/isExtensible/return-is-abrupt.js
new file mode 100644
index 0000000000000000000000000000000000000000..d288dee824b71c238850278112aa0a1f8a440b78
--- /dev/null
+++ b/test/built-ins/Proxy/isExtensible/return-is-abrupt.js
@@ -0,0 +1,25 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 9.5.3
+description: >
+    Trap returns abrupt.
+info: >
+    [[IsExtensible]] ( )
+
+    ...
+    8. Let booleanTrapResult be ToBoolean(Call(trap, handler, «target»)).
+    9. ReturnIfAbrupt(booleanTrapResult).
+    ...
+includes: [Test262Error.js]
+---*/
+
+var p = new Proxy({}, {
+    isExtensible: function(t) {
+        throw new Test262Error();
+    }
+});
+
+assert.throws(Test262Error, function() {
+    Object.isExtensible(p);
+});
diff --git a/test/built-ins/Proxy/isExtensible/return-is-boolean.js b/test/built-ins/Proxy/isExtensible/return-is-boolean.js
new file mode 100644
index 0000000000000000000000000000000000000000..29d54369ed8c51d644850898b20d07b61d07face
--- /dev/null
+++ b/test/built-ins/Proxy/isExtensible/return-is-boolean.js
@@ -0,0 +1,24 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 9.5.3
+description: >
+    The trap returns a boolean result.
+---*/
+
+var target = {};
+var p = new Proxy(target, {
+    isExtensible: function(t) {
+        if ( Object.isExtensible(t) ) {
+            return 1;
+        } else {
+            return 0;
+        }
+    }
+});
+
+assert.sameValue(Object.isExtensible(p), true);
+
+Object.preventExtensions(target);
+
+assert.sameValue(Object.isExtensible(p), false);
diff --git a/test/built-ins/Proxy/isExtensible/return-is-different-from-target.js b/test/built-ins/Proxy/isExtensible/return-is-different-from-target.js
new file mode 100644
index 0000000000000000000000000000000000000000..9c5ee18c99312413bbee1560cedaa922a38916aa
--- /dev/null
+++ b/test/built-ins/Proxy/isExtensible/return-is-different-from-target.js
@@ -0,0 +1,25 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 9.5.3
+description: >
+    Throws a TypeError exception if boolean trap result is not the same as
+    target.[[IsExtensible]]() result
+info: >
+    [[IsExtensible]] ( )
+
+    ...
+    12. If SameValue(booleanTrapResult, targetResult) is false, throw a
+    TypeError exception.
+    ...
+---*/
+
+var p = new Proxy({}, {
+    isExtensible: function(t) {
+        return false;
+    }
+});
+
+assert.throws(TypeError, function() {
+    Object.isExtensible(p);
+});
diff --git a/test/built-ins/Proxy/isExtensible/return-same-result-from-target.js b/test/built-ins/Proxy/isExtensible/return-same-result-from-target.js
new file mode 100644
index 0000000000000000000000000000000000000000..4858765c37643c0251f37eefb48335e637331819
--- /dev/null
+++ b/test/built-ins/Proxy/isExtensible/return-same-result-from-target.js
@@ -0,0 +1,20 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 9.5.3
+description: >
+    Return trap result.
+---*/
+
+var target = {};
+var p = new Proxy(target, {
+    isExtensible: function(t) {
+        return Object.isExtensible(t);
+    }
+});
+
+assert.sameValue(Object.isExtensible(p), true);
+
+Object.preventExtensions(target);
+
+assert.sameValue(Object.isExtensible(p), false);
diff --git a/test/built-ins/Proxy/isExtensible/trap-is-not-callable.js b/test/built-ins/Proxy/isExtensible/trap-is-not-callable.js
new file mode 100644
index 0000000000000000000000000000000000000000..adca7938336a90e22d6d7020aed968b875054ea4
--- /dev/null
+++ b/test/built-ins/Proxy/isExtensible/trap-is-not-callable.js
@@ -0,0 +1,30 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 9.5.3
+description: >
+    Throws a TypeError exception if trap is not callable.
+info: >
+    [[IsExtensible]] ( )
+
+    ...
+    1. Let handler be the value of the [[ProxyHandler]] internal slot of O.
+    ...
+    5. Let trap be GetMethod(handler, "isExtensible").
+    ...
+        7.3.9 GetMethod (O, P)
+        ...
+        2. Let func be GetV(O, P).
+        5. If IsCallable(func) is false, throw a TypeError exception.
+        ...
+---*/
+
+
+var target = {};
+var p = new Proxy(target, {
+    isExtensible: {}
+});
+
+assert.throws(TypeError, function() {
+    Object.isExtensible(p);
+});
diff --git a/test/built-ins/Proxy/isExtensible/trap-is-undefined.js b/test/built-ins/Proxy/isExtensible/trap-is-undefined.js
new file mode 100644
index 0000000000000000000000000000000000000000..a69acac26ddfc5b68765123438f4d187f1064121
--- /dev/null
+++ b/test/built-ins/Proxy/isExtensible/trap-is-undefined.js
@@ -0,0 +1,23 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 9.5.3
+description: >
+    Return target.[[IsExtensible]]() if trap is undefined.
+info: >
+    [[IsExtensible]] ( )
+
+    ...
+    7. If trap is undefined, then
+        a. Return target.[[IsExtensible]]().
+    ...
+---*/
+
+var target = {};
+var p = new Proxy(target, {});
+
+assert.sameValue(Object.isExtensible(p), true);
+
+Object.preventExtensions(target);
+
+assert.sameValue(Object.isExtensible(p), false);