1 files changed, 37 insertions, 15 deletions
diff --git a/js/src/tests/ecma_6/shell.js b/js/src/tests/ecma_6/shell.js
index 06be6f2db..756da9f36 100644
--- a/js/src/tests/ecma_6/shell.js
+++ b/js/src/tests/ecma_6/shell.js
@@ -3,21 +3,43 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 (function(global) {
-  /** Yield every permutation of the elements in some array. */
-  global.Permutations = function* Permutations(items) {
-      if (items.length == 0) {
-          yield [];
-      } else {
-          items = items.slice(0);
-          for (let i = 0; i < items.length; i++) {
-              let swap = items[0];
-              items[0] = items[i];
-              items[i] = swap;
-              for (let e of Permutations(items.slice(1, items.length)))
-                  yield [items[0]].concat(e);
-          }
-      }
-  };
+    /** Yield every permutation of the elements in some array. */
+    global.Permutations = function* Permutations(items) {
+        if (items.length == 0) {
+            yield [];
+        } else {
+            items = items.slice(0);
+            for (let i = 0; i < items.length; i++) {
+                let swap = items[0];
+                items[0] = items[i];
+                items[i] = swap;
+                for (let e of Permutations(items.slice(1, items.length)))
+                    yield [items[0]].concat(e);
+            }
+        }
+    };
+
+    /** Make an iterator with a return method. */
+    global.makeIterator = function makeIterator(overrides) {
+        var throwMethod;
+        if (overrides && overrides.throw)
+            throwMethod = overrides.throw;
+        var iterator = {
+            throw: throwMethod,
+            next: function(x) {
+                if (overrides && overrides.next)
+                    return overrides.next(x);
+                return { done: false };
+            },
+            return: function(x) {
+                if (overrides && overrides.ret)
+                    return overrides.ret(x);
+                return { done: true };
+            }
+        };
+
+        return function() { return iterator; };
+    };
 })(this);
 
 if (typeof assertThrowsInstanceOf === 'undefined') {