1 files changed, 43 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/RegExp/prototype/Symbol.replace/g-pos-decrement.js b/js/src/tests/test262/built-ins/RegExp/prototype/Symbol.replace/g-pos-decrement.js
new file mode 100644
index 0000000000..ed390cd2ed
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+++ b/js/src/tests/test262/built-ins/RegExp/prototype/Symbol.replace/g-pos-decrement.js
@@ -0,0 +1,43 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+description: >
+    Behavior when position is decremented during result accumulation
+es6id: 21.2.5.8
+info: |
+    16. Repeat, for each result in results,
+        [...]
+        p. If position ≥ nextSourcePosition, then
+           i. NOTE position should not normally move backwards. If it does, it
+              is an indication of an ill-behaving RegExp subclass or use of an
+              access triggered side-effect to change the global flag or other
+              characteristics of rx. In such cases, the corresponding
+              substitution is ignored.
+           ii. Let accumulatedResult be the String formed by concatenating the
+               code units of the current value of accumulatedResult with the
+               substring of S consisting of the code units from
+               nextSourcePosition (inclusive) up to position (exclusive) and
+               with the code units of replacement.
+           iii. Let nextSourcePosition be position + matchLength.
+features: [Symbol.replace]
+---*/
+
+var r = /./g;
+var callCount = 0;
+r.exec = function() {
+  callCount += 1;
+
+  if (callCount === 1) {
+    return { index: 3, length: 1, 0: 0 };
+  } else if (callCount === 2) {
+    return { index: 1, length: 1, 0: 0 };
+  }
+
+  return null;
+};
+
+assert.sameValue(r[Symbol.replace]('abcde', 'X'), 'abcXe');
+assert.sameValue(callCount, 3);
+
+reportCompare(0, 0);