Add --gtest_filter support to run_test_cases.py.

tools/isolate/run_test_cases_test.py

Index: tools/isolate/run_test_cases_test.py
diff --git a/tools/isolate/run_test_cases_test.py b/tools/isolate/run_test_cases_test.py
index 8f06a6c65e4652926c009d686d7d93e5fc655b2b..b0b56368dac3067645d97742fdd548d83187688c 100755
--- a/tools/isolate/run_test_cases_test.py
+++ b/tools/isolate/run_test_cases_test.py
@@ -96,6 +96,23 @@ class RunTestCases(unittest.TestCase):
     self.assertEquals('Sleeping.\nSlept.\n', output)
     self.assertEquals(0, code)
 
+  def test_gtest_filter(self):
+    old = run_test_cases.run_test_cases
+    exe = os.path.join(ROOT_DIR, 'data', 'gtest_fake', 'gtest_fake_pass.py')
+    def expect(executable, test_cases, jobs, timeout, no_dump):
+      self.assertEquals(exe, executable)
+      self.assertEquals(['Foo.Bar1', 'Foo.Bar3'], test_cases)
+      self.assertEquals(run_test_cases.num_processors(), jobs)
+      self.assertEquals(120, timeout)
+      self.assertEquals(None, no_dump)
+      return 89
+    try:
+      run_test_cases.run_test_cases = expect
+      result = run_test_cases.main([exe, '--gtest_filter=Foo.Bar*-*.Bar2'])
+      self.assertEquals(89, result)
+    finally:
+      run_test_cases.run_test_cases = old
+
 
 class WorkerPoolTest(unittest.TestCase):
   def test_normal(self):