MSVS: Normalize paths against gyp directory.

test/msvs/filters/gyptest-filters-2010.py

 #!/usr/bin/env python
 
 # Copyright (c) 2014 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 Verifies that extra filters are pruned correctly for Visual Studio 2010
 and later.
 """
 
 import TestGyp
+import os
 
 
 test = TestGyp.TestGyp(formats=['msvs'])
 
 test.run_gyp('filters.gyp', '-G', 'standalone', '-G', 'msvs_version=2010')
 
 test.must_not_exist('no_source_files.vcxproj.filters')
 
 test.must_not_exist('one_source_file.vcxproj.filters')
 
@@ skipping 23 matching lines @@
     </ClCompile>
     <ClCompile Include="..\\folder1\\nested\\b.c">
       <Filter>folder1\\nested</Filter>
     </ClCompile>
     <ClCompile Include="..\\folder1\\other\\c.c">
       <Filter>folder1\\other</Filter>
     </ClCompile>
   </ItemGroup>
 '''.replace('\n', '\r\n'))
 
+subdir_gyp = os.path.join('subdir', 'subdir.gyp')
+test.run_gyp(subdir_gyp, '-G', 'standalone', '-G', 'msvs_version=2010')
+
+test.must_contain(os.path.join('subdir', 'normalize.vcxproj.filters'), '''\
+  <ItemGroup>
+    <ClCompile Include="folder1\\a.c">
+      <Filter>folder1</Filter>
+    </ClCompile>
+    <ClCompile Include="folder2\\b.c">
+      <Filter>folder2</Filter>
+    </ClCompile>
+  </ItemGroup>
+'''.replace('\n', '\r\n'))
 
 test.pass_test()