class_docstr: Tests the env variable or the command line flag to filter tests.
docstr: Tests an empty filter.
docstr_tok: ["Tests","an","empty","filter","."]
code: def testEmptyFilter(self):
      """Tests an empty filter."""
  
      self.RunAndVerify("", [])
      self.RunAndVerifyWithSharding("", 1, [])
      self.RunAndVerifyWithSharding("", 2, [])
  
imports: import os
  import re
  import sys
  from googletest.test import gtest_test_utils
label_desc: Use image node_id 10 for calling the GTestFilterUnitTest obj's underlying member method code with example usage: obj.testEmptyFilter() without return types