1 files changed, 53 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/Array/prototype/concat/is-concat-spreadable-proxy.js b/js/src/tests/test262/built-ins/Array/prototype/concat/is-concat-spreadable-proxy.js
new file mode 100644
index 0000000000..52dde72e68
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/concat/is-concat-spreadable-proxy.js
@@ -0,0 +1,53 @@
+// Copyright (C) 2016 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-isconcatspreadable
+description: >
+  Proxies who final targets are arrays are considered spreadable
+info: |
+  [...]
+  5. Repeat, while items is not empty
+     a. Remove the first element from items and let E be the value of the
+        element.
+     b. Let spreadable be ? IsConcatSpreadable(E).
+     c. If spreadable is true, then
+        [...]
+     e. Else E is added as a single item rather than spread,
+        [...]
+
+  ES6 22.1.3.1.1: Runtime Semantics: IsConcatSpreadable ( O )
+
+  1. If Type(O) is not Object, return false.
+  2. Let spreadable be ? Get(O, @@isConcatSpreadable).
+  3. If spreadable is not undefined, return ToBoolean(spreadable).
+  4. Return ? IsArray(O).
+
+  7.2.2 IsArray
+
+  [...]
+  3. If argument is a Proxy exotic object, then
+     a. If the value of the [[ProxyHandler]] internal slot of argument is null,
+        throw a TypeError exception.
+     b. Let target be the value of the [[ProxyTarget]] internal slot of
+        argument.
+     c. Return ? IsArray(target).
+features: [Proxy, Symbol.isConcatSpreadable]
+---*/
+
+var arrayProxy = new Proxy([], {});
+var arrayProxyProxy = new Proxy(arrayProxy, {});
+var spreadable = {};
+spreadable[Symbol.isConcatSpreadable] = true;
+var spreadableProxy = new Proxy(spreadable, {});
+
+assert.sameValue([].concat(arrayProxy).length, 0, 'The value of [].concat(arrayProxy).length is expected to be 0');
+assert.sameValue(
+  [].concat(arrayProxyProxy).length, 0, 'The value of [].concat(arrayProxyProxy).length is expected to be 0'
+);
+assert.sameValue(
+  [].concat(spreadableProxy).length,
+  0,
+  'The value of [].concat(spreadableProxy).length is expected to be 0'
+);
+
+reportCompare(0, 0);