class_docstr: Tests the env variable or the command line flag to filter tests.
docstr: Tests the behavior of not specifying the filter.
code: def testDefaultBehavior(self):
      """Tests the behavior of not specifying the filter."""
  
      self.RunAndVerify(None, ACTIVE_TESTS)
  
imports: import os
  import re
  import sys
  from googletest.test import gtest_test_utils
label_desc: Use image node_id 8 for calling the GTestFilterUnitTest obj's underlying member method code with example usage: obj.testDefaultBehavior() without return types