Makefiles will always contain tabs so make the notab check filter them out.

tests/presubmit_unittest.py

 #!/usr/bin/python
 # Copyright (c) 2010 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Unit tests for presubmit_support.py and presubmit_canned_checks.py."""
 
 import StringIO
 
 # Fixes include path.
@@ skipping 1143 matching lines @@
     results2 = check(input_api2, presubmit.OutputApi)
     self.assertEquals(len(results2), 1)
     self.assertEquals(results2[0].__class__, error_type)
 
   def ContentTest(self, check, content1, content2, error_type):
     change1 = presubmit.Change('foo1', 'foo1\n', self.fake_root_dir, None,
                                0, 0)
     input_api1 = self.MockInputApi(change1, False)
     affected_file = self.mox.CreateMock(presubmit.SvnAffectedFile)
     affected_file.LocalPath().AndReturn('foo.cc')
+    # Format is (file, line number, line content)
     output1 = [
       (affected_file, 42, 'yo, ' + content1),
       (affected_file, 43, 'yer'),
       (affected_file, 23, 'ya'),
     ]
     input_api1.RightHandSideLines(mox.IgnoreArg()).AndReturn(output1)
     change2 = presubmit.Change('foo2', 'foo2\n', self.fake_root_dir, None,
                                0, 0)
     input_api2 = self.MockInputApi(change2, False)
     output2 = [
@@ skipping 146 matching lines @@
     self.ReadFileTest(
         presubmit_canned_checks.CheckChangeHasNoCrAndHasOnlyOneEol,
         "Hey!\nHo!\n", "Hey!\r\nHo!\r\n",
         presubmit.OutputApi.PresubmitPromptWarning)
 
   def testCannedCheckChangeHasNoTabs(self):
     self.ContentTest(presubmit_canned_checks.CheckChangeHasNoTabs,
                      'blah blah', 'blah\tblah',
                      presubmit.OutputApi.PresubmitPromptWarning)
 
+    # Make sure makefiles are ignored.
+    change1 = presubmit.Change('foo1', 'foo1\n', self.fake_root_dir, None,
+                               0, 0)
+    input_api1 = self.MockInputApi(change1, False)
+    affected_file1 = self.mox.CreateMock(presubmit.SvnAffectedFile)
+    affected_file1.LocalPath().AndReturn('foo.cc')
+    affected_file2 = self.mox.CreateMock(presubmit.SvnAffectedFile)
+    affected_file2.LocalPath().AndReturn('foo/Makefile')
+    affected_file3 = self.mox.CreateMock(presubmit.SvnAffectedFile)
+    affected_file3.LocalPath().AndReturn('makefile')
+    # Only this one will trigger.
+    affected_file4 = self.mox.CreateMock(presubmit.SvnAffectedFile)
+    affected_file4.LocalPath().AndReturn('makefile.foo')
+    affected_file4.LocalPath().AndReturn('makefile.foo')
+    output1 = [
+      (affected_file1, 42, 'yo, '),
+      (affected_file2, 43, 'yer\t'),
+      (affected_file3, 45, 'yr\t'),
+      (affected_file4, 46, 'ye\t'),
+    ]
+    def test(source_filter):
+      for i in output1:
+        if source_filter(i[0]):
+          yield i
+    # Override the mock of these functions.
+    input_api1.FilterSourceFile = lambda x: x
+    input_api1.RightHandSideLines = test
+    self.mox.ReplayAll()
+
+    results1 = presubmit_canned_checks.CheckChangeHasNoTabs(input_api1,
+        presubmit.OutputApi, None)
+    self.assertEquals(len(results1), 1)
+    self.assertEquals(results1[0].__class__,
+        presubmit.OutputApi.PresubmitPromptWarning)
+    self.assertEquals(results1[0]._long_text,
+        'makefile.foo, line 46')
+
+
   def testCannedCheckLongLines(self):
     check = lambda x,y,z: presubmit_canned_checks.CheckLongLines(x, y, 10, z)
     self.ContentTest(check, '', 'blah blah blah',
                      presubmit.OutputApi.PresubmitPromptWarning)
 
   def testCheckChangeSvnEolStyleCommit(self):
     # Test CheckSvnProperty at the same time.
     self.SvnPropertyTest(presubmit_canned_checks.CheckChangeSvnEolStyle,
                          'svn:eol-style', 'LF', '', True,
                          presubmit.OutputApi.PresubmitError, True)
@@ skipping 319 matching lines @@
     results = presubmit_canned_checks.CheckBuildbotPendingBuilds(
         input_api, presubmit.OutputApi, 'uurl', 2, ('foo'))
     self.assertEquals(len(results), 1)
     self.assertEquals(results[0].__class__,
         presubmit.OutputApi.PresubmitNotifyResult)
 
 
 if __name__ == '__main__':
   import unittest
   unittest.main()