Fix orphaned wpt -expected.txt file deletion logic.

third_party/WebKit/Tools/Scripts/webkitpy/w3c/test_importer_unittest.py

 # Copyright 2016 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.
 
 import collections
 
 from webkitpy.common.checkout.git_mock import MockGit
 from webkitpy.common.host_mock import MockHost
 from webkitpy.common.system.executive_mock import MockExecutive
 from webkitpy.common.system.log_testing import LoggingTestCase
@@ skipping 176 matching lines @@
         self.assertEqual(importer.get_directory_owners(), {})
 
     def test_cc_part(self):
         directory_owners = {
             ('someone@chromium.org',): ['external/wpt/foo', 'external/wpt/bar'],
             ('x@chromium.org', 'y@chromium.org'): ['external/wpt/baz'],
         }
         self.assertEqual(
             TestImporter._cc_part(directory_owners),
             ['--cc=someone@chromium.org', '--cc=x@chromium.org', '--cc=y@chromium.org'])
+
+    def test_delete_orphaned_baselines(self):
+        host = MockHost()
+        dest_path = '/mock-checkout/third_party/WebKit/LayoutTests/external/wpt'
+        host.filesystem.write_text_file(dest_path + '/b-expected.txt', '')
+        host.filesystem.write_text_file(dest_path + '/b.x-expected.txt', '')
+        host.filesystem.write_text_file(dest_path + '/b.x.html', '')
+        importer = TestImporter(host)
+        importer._delete_orphaned_baselines(dest_path)
+        self.assertFalse(host.filesystem.exists(dest_path + '/b-expected.txt'))
+        self.assertTrue(host.filesystem.exists(dest_path + '/b.x-expected.txt'))
+        self.assertTrue(host.filesystem.exists(dest_path + '/b.x.html'))