old_contents: try:
      from StringIO import StringIO
  except ImportError:
      from io import StringIO
  from mock import patch
  from unittest import TestCase
  
  from mlx.warnings import WarningsPlugin
  
  
  class TestXMLRunnerWarnings(TestCase):
      def setUp(self):
          self.warnings = WarningsPlugin(verbose=True)
          self.warnings.activate_checker_name('xmlrunner')
  
      def test_no_warning(self):
          dut = 'This should not be treated as warning'
          self.warnings.check(dut)
          self.assertEqual(self.warnings.return_count(), 0)
  
      def test_single_warning(self):
          dut = 'ERROR [0.000s]: test_some_error_test (something.anything.somewhere)'
          with patch('sys.stdout', new=StringIO()) as fake_out:
              self.warnings.check(dut)
          self.assertEqual(self.warnings.return_count(), 1)
          self.assertRegexpMatches(fake_out.getvalue(), dut)
  
      def test_single_warning_mixed(self):
          dut1 = 'This1 should not be treated as warning'
          dut2 = 'ERROR [0.000s]: test_some_error_test (something.anything.somewhere)'
          dut3 = 'This should not be treated as warning2'
          with patch('sys.stdout', new=StringIO()) as fake_out:
              self.warnings.check(dut1)
              self.warnings.check(dut2)
              self.warnings.check(dut3)
          self.assertEqual(self.warnings.return_count(), 1)
          self.assertRegexpMatches(fake_out.getvalue(), dut2)
  
      def test_multiline(self):
          duterr1 = "ERROR [0.000s]: test_some_error_test (something.anything.somewhere) \"Some test functions\" that does not match old title \"Some freaky test functions\"\n"
          duterr2 = "ERROR [0.000s]: ignoring title \"Some test functions\" that does not match old title \"Some freaky test functions\"\n"
          dut = "This1 should not be treated as warning\n"
          dut += duterr1
          dut += "This should not be treated as warning2\n"
          dut += duterr2
          with patch('sys.stdout', new=StringIO()) as fake_out:
              self.warnings.check(dut)
          self.assertEqual(self.warnings.return_count(), 2)
          self.assertRegexpMatches(fake_out.getvalue(), duterr1)
          self.assertRegexpMatches(fake_out.getvalue(), duterr2)
  
  
new_contents: try:
      from StringIO import StringIO
  except ImportError:
      from io import StringIO
  from mock import patch
  from unittest import TestCase
  
  from mlx.warnings import WarningsPlugin
  
  
  class TestXMLRunnerWarnings(TestCase):
      def setUp(self):
          self.warnings = WarningsPlugin(verbose=True)
          self.warnings.activate_checker_name('xmlrunner')
  
      def test_no_warning(self):
          dut = 'This should not be treated as warning'
          self.warnings.check(dut)
          self.assertEqual(self.warnings.return_count(), 0)
  
      def test_single_warning(self):
          dut = 'ERROR [0.000s]: test_some_error_test (something.anything.somewhere)'
          with patch('sys.stdout', new=StringIO()) as fake_out:
              self.warnings.check(dut)
          self.assertEqual(self.warnings.return_count(), 1)
          self.assertIn(dut, fake_out.getvalue())
  
      def test_single_warning_mixed(self):
          dut1 = 'This1 should not be treated as warning'
          dut2 = 'ERROR [0.000s]: test_some_error_test (something.anything.somewhere)'
          dut3 = 'This should not be treated as warning2'
          with patch('sys.stdout', new=StringIO()) as fake_out:
              self.warnings.check(dut1)
              self.warnings.check(dut2)
              self.warnings.check(dut3)
          self.assertEqual(self.warnings.return_count(), 1)
          self.assertIn(dut2, fake_out.getvalue())
  
      def test_multiline(self):
          duterr1 = "ERROR [0.000s]: test_some_error_test (something.anything.somewhere) \"Some test functions\" that does not match old title \"Some freaky test functions\"\n"
          duterr2 = "ERROR [0.000s]: ignoring title \"Some test functions\" that does not match old title \"Some freaky test functions\"\n"
          dut = "This1 should not be treated as warning\n"
          dut += duterr1
          dut += "This should not be treated as warning2\n"
          dut += duterr2
          with patch('sys.stdout', new=StringIO()) as fake_out:
              self.warnings.check(dut)
          self.assertEqual(self.warnings.return_count(), 2)
          self.assertIn(duterr1, fake_out.getvalue())
          self.assertIn(duterr2, fake_out.getvalue())
  
  
subject: Change regexMatch to assertIn