1 files changed, 36 insertions, 0 deletions
diff --git a/js/src/tests/test262/annexB/built-ins/String/prototype/substr/length-undef.js b/js/src/tests/test262/annexB/built-ins/String/prototype/substr/length-undef.js
new file mode 100644
index 0000000000..abaee99f0e
--- /dev/null
+++ b/js/src/tests/test262/annexB/built-ins/String/prototype/substr/length-undef.js
@@ -0,0 +1,36 @@
+// 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-string.prototype.substr
+es6id: B.2.3.1
+description: Behavior when "length" is not defined
+info: |
+    [...]
+    4. If length is undefined, let end be +∞; otherwise let end be ?
+       ToInteger(length).
+    [...]
+    7. Let resultLength be min(max(end, 0), size - intStart).
+    8. If resultLength ≤ 0, return the empty String "".
+    9. Return a String containing resultLength consecutive code units from S
+       beginning with the code unit at index intStart.
+---*/
+
+assert.sameValue('abc'.substr(0), 'abc', 'start: 0, length: unspecified');
+assert.sameValue('abc'.substr(1), 'bc', 'start: 1, length: unspecified');
+assert.sameValue('abc'.substr(2), 'c', 'start: 2, length: unspecified');
+assert.sameValue('abc'.substr(3), '', 'start: 3, length: unspecified');
+
+assert.sameValue(
+  'abc'.substr(0, undefined), 'abc', 'start: 0, length: undefined'
+);
+assert.sameValue(
+  'abc'.substr(1, undefined), 'bc', 'start: 1, length: undefined'
+);
+assert.sameValue(
+  'abc'.substr(2, undefined), 'c', 'start: 2, length: undefined'
+);
+assert.sameValue(
+  'abc'.substr(3, undefined), '', 'start: 3, length: undefined'
+);
+
+reportCompare(0, 0);