1 files changed, 58 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/Function/prototype/toString/built-in-function-object.js b/js/src/tests/test262/built-ins/Function/prototype/toString/built-in-function-object.js
new file mode 100644
index 0000000000..9aebef3089
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Function/prototype/toString/built-in-function-object.js
@@ -0,0 +1,58 @@
+// Copyright (C) 2018 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-function.prototype.tostring
+description: >
+  toString of built-in Function object
+info: |
+  ...
+  If func is a built-in Function object, then return an implementation-dependent String source code representation of func.
+  The representation must have the syntax of a NativeFunction.
+  ...
+
+  NativeFunction:
+    function NativeFunctionAccessor_opt IdentifierName_opt ( FormalParameters ) { [ native code ] }
+  NativeFunctionAccessor :
+    get
+    set
+
+includes: [nativeFunctionMatcher.js, wellKnownIntrinsicObjects.js]
+features: [arrow-function, Reflect, Array.prototype.includes]
+---*/
+
+const visited = [];
+function visit(ns, path) {
+  if (visited.includes(ns)) {
+    return;
+  }
+  visited.push(ns);
+
+  if (typeof ns === 'function') {
+    assertNativeFunction(ns, path);
+  }
+  if (typeof ns !== 'function' && (typeof ns !== 'object' || ns === null)) {
+    return;
+  }
+
+  const descriptors = Object.getOwnPropertyDescriptors(ns);
+  Reflect.ownKeys(descriptors)
+    .forEach((name) => {
+      const desc = descriptors[name];
+      const p = typeof name === 'symbol'
+        ? `${path}[Symbol(${name.description})]`
+        : `${path}.${name}`;
+      if ('value' in desc) {
+        visit(desc.value, p);
+      } else {
+        visit(desc.get, p);
+        visit(desc.set, p);
+      }
+    });
+}
+
+WellKnownIntrinsicObjects.forEach((intrinsic) => {
+  visit(intrinsic.value, intrinsic.name);
+});
+assert.notSameValue(visited.length, 0);
+
+reportCompare(0, 0);