Added test for bug 176 (zero length matches should fail in quantifiers).

Review URL: http://codereview.chromium.org/13381

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@960 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

test/mjsunit/bugs/bug-176.js

+// Copyright 2008 the V8 project authors. All rights reserved.
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+// modification, are permitted provided that the following conditions are
+// met:
+//
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+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
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+//       with the distribution.
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+//
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+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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+
+// See http://code.google.com/p/v8/issues/detail?id=176
+
+assertEquals("f,",
+             "foo".match(/(?:(?=(f)o))?f/).toString(),
+             "zero length match in (?:) with capture in lookahead");
+assertEquals("f,",
+             "foo".match(/(?=(f)o)?f/).toString(),
+             "zero length match in (?=) with capture in lookahead");
+assertEquals("fo,f",
+             "foo".match(/(?:(?=(f)o)f)?o/),
+             "non-zero length match with capture in lookahead");
+assertEquals("fo,f",
+             "foo".match(/(?:(?=(f)o)f?)?o/),
+             "non-zero length match with greedy ? in (?:)");
+assertEquals("fo,f",
+             "foo".match(/(?:(?=(f)o)f??)?o/),
+             "non-zero length match with non-greedy ? in (?:), o forces backtrack");
+assertEquals("fo,f",
+             "foo".match(/(?:(?=(f)o)f??)?./),
+             "non-zero length match with non-greedy ? in (?:), zero length match causes backtrack");
+assertEquals("f,",
+             "foo".match(/(?:(?=(f)o)fx)?./),
+             "x causes backtrack inside (?:)");