diff -r 000000000000 -r 4f2f89ce4247 WebKitTools/Scripts/webkitpy/style/checkers/common_unittest.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebKitTools/Scripts/webkitpy/style/checkers/common_unittest.py	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,94 @@
+# Copyright (C) 2010 Chris Jerdonek (cjerdonek@webkit.org)
+#
+# 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.
+
+"""Unit tests for common.py."""
+
+import unittest
+
+from common import CarriageReturnChecker
+
+
+# FIXME: The unit tests for the cpp, text, and common checkers should
+#        share supporting test code. This can include, for example, the
+#        mock style error handling code and the code to check that all
+#        of a checker's categories are covered by the unit tests.
+#        Such shared code can be located in a shared test file, perhaps
+#        even this file.
+class CarriageReturnCheckerTest(unittest.TestCase):
+
+    """Tests check_no_carriage_return()."""
+
+    _category = "whitespace/carriage_return"
+    _confidence = 1
+    _expected_message = ("One or more unexpected \\r (^M) found; "
+                         "better to use only a \\n")
+
+    def setUp(self):
+        self._style_errors = [] # The list of accumulated style errors.
+
+    def _mock_style_error_handler(self, line_number, category, confidence,
+                                  message):
+        """Append the error information to the list of style errors."""
+        error = (line_number, category, confidence, message)
+        self._style_errors.append(error)
+
+    def assert_carriage_return(self, input_lines, expected_lines, error_lines):
+        """Process the given line and assert that the result is correct."""
+        handle_style_error = self._mock_style_error_handler
+
+        checker = CarriageReturnChecker(handle_style_error)
+        output_lines = checker.check(input_lines)
+
+        # Check both the return value and error messages.
+        self.assertEquals(output_lines, expected_lines)
+
+        expected_errors = [(line_number, self._category, self._confidence,
+                            self._expected_message)
+                           for line_number in error_lines]
+        self.assertEquals(self._style_errors, expected_errors)
+
+    def test_ends_with_carriage(self):
+        self.assert_carriage_return(["carriage return\r"],
+                                    ["carriage return"],
+                                    [1])
+
+    def test_ends_with_nothing(self):
+        self.assert_carriage_return(["no carriage return"],
+                                    ["no carriage return"],
+                                    [])
+
+    def test_ends_with_newline(self):
+        self.assert_carriage_return(["no carriage return\n"],
+                                    ["no carriage return\n"],
+                                    [])
+
+    def test_carriage_in_middle(self):
+        # The CarriageReturnChecker checks only the final character
+        # of each line.
+        self.assert_carriage_return(["carriage\r in a string"],
+                                    ["carriage\r in a string"],
+                                    [])
+
+    def test_multiple_errors(self):
+        self.assert_carriage_return(["line1", "line2\r", "line3\r"],
+                                    ["line1", "line2", "line3"],
+                                    [2, 3])