Reapply "Port regexp tests from V8 to Dart."

tests/corelib/regexp/toString_test.dart

+// Copyright (c) 2014, the Dart project authors. All rights reserved.
+// Copyright 2013 the V8 project authors. All rights reserved.
+// Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+// 1.  Redistributions of source code must retain the above copyright
+//     notice, this list of conditions and the following disclaimer.
+// 2.  Redistributions in binary form must reproduce the above copyright
+//     notice, this list of conditions and the following disclaimer in the
+//     documentation and/or other materials provided with the distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS 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, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+// ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import 'v8_regexp_utils.dart';
+import 'package:expect/expect.dart';
+
+void main() {
+  dynamic testForwardSlash(pattern, _string)
+  {
+      var string = _string;
+
+      var re1 = new RegExp(pattern);
+
+      return re1.hasMatch(string);
+  }
+
+  dynamic testLineTerminator(pattern)
+  {
+      var re1 = new RegExp(pattern);
+
+      return new RegExp(r"\n|\r|\u2028|\u2029").hasMatch(re1.toString());
+  }
+
+  // These strings are equivalent, since the '\' is identity escaping the '/' at the string level.
+  shouldBeTrue(testForwardSlash("^/\$", "/"));
+  shouldBeTrue(testForwardSlash("^\/\$", "/"));
+  // This string passes "^\/$" to the RegExp, so the '/' is escaped in the re!
+  shouldBeTrue(testForwardSlash("^\\/\$", "/"));
+  // These strings pass "^\\/$" and "^\\\/$" respectively to the RegExp, giving one '\' to match.
+  shouldBeTrue(testForwardSlash("^\\\\/\$", "\\/"));
+  shouldBeTrue(testForwardSlash("^\\\\\\/\$", "\\/"));
+  // These strings match two backslashes (the second with the '/' escaped).
+  shouldBeTrue(testForwardSlash("^\\\\\\\\/\$", "\\\\/"));
+  shouldBeTrue(testForwardSlash("^\\\\\\\\\\/\$", "\\\\/"));
+  // Test that nothing goes wrongif there are multiple forward slashes!
+  shouldBeTrue(testForwardSlash("x/x/x", "x/x/x"));
+  shouldBeTrue(testForwardSlash("x\\/x/x", "x/x/x"));
+  shouldBeTrue(testForwardSlash("x/x\\/x", "x/x/x"));
+  shouldBeTrue(testForwardSlash("x\\/x\\/x", "x/x/x"));
+
+  shouldBeFalse(testLineTerminator("\\n"));
+  shouldBeFalse(testLineTerminator("\\\\n"));
+  shouldBeFalse(testLineTerminator("\\r"));
+  shouldBeFalse(testLineTerminator("\\\\r"));
+  shouldBeFalse(testLineTerminator("\\u2028"));
+  shouldBeFalse(testLineTerminator("\\\\u2028"));
+  shouldBeFalse(testLineTerminator("\\u2029"));
+  shouldBeFalse(testLineTerminator("\\\\u2029"));
+}