old_contents: import os
  import unittest
  
  import pytest
  
  
  class TestMarkerlib(unittest.TestCase):
  
      @pytest.mark.importorskip('ast')
      def test_markers(self):
          from _markerlib import interpret, default_environment, compile
  
          os_name = os.name
  
          self.assertTrue(interpret(""))
  
          self.assertTrue(interpret("os.name != 'buuuu'"))
          self.assertTrue(interpret("os_name != 'buuuu'"))
          self.assertTrue(interpret("python_version > '1.0'"))
          self.assertTrue(interpret("python_version < '5.0'"))
          self.assertTrue(interpret("python_version <= '5.0'"))
          self.assertTrue(interpret("python_version >= '1.0'"))
          self.assertTrue(interpret("'%s' in os.name" % os_name))
          self.assertTrue(interpret("'%s' in os_name" % os_name))
          self.assertTrue(interpret("'buuuu' not in os.name"))
  
          self.assertFalse(interpret("os.name == 'buuuu'"))
          self.assertFalse(interpret("os_name == 'buuuu'"))
          self.assertFalse(interpret("python_version < '1.0'"))
          self.assertFalse(interpret("python_version > '5.0'"))
          self.assertFalse(interpret("python_version >= '5.0'"))
          self.assertFalse(interpret("python_version <= '1.0'"))
          self.assertFalse(interpret("'%s' not in os.name" % os_name))
          self.assertFalse(interpret("'buuuu' in os.name and python_version >= '5.0'"))
          self.assertFalse(interpret("'buuuu' in os_name and python_version >= '5.0'"))
  
          environment = default_environment()
          environment['extra'] = 'test'
          self.assertTrue(interpret("extra == 'test'", environment))
          self.assertFalse(interpret("extra == 'doc'", environment))
  
          def raises_nameError():
              try:
                  interpret("python.version == '42'")
              except NameError:
                  pass
              else:
                  raise Exception("Expected NameError")
  
          raises_nameError()
  
          def raises_syntaxError():
              try:
                  interpret("(x for x in (4,))")
              except SyntaxError:
                  pass
              else:
                  raise Exception("Expected SyntaxError")
  
          raises_syntaxError()
  
          statement = "python_version == '5'"
          self.assertEqual(compile(statement).__doc__, statement)
  
  
new_contents: import os
  
  import pytest
  
  
  class TestMarkerlib:
  
      @pytest.mark.importorskip('ast')
      def test_markers(self):
          from _markerlib import interpret, default_environment, compile
  
          os_name = os.name
  
          assert interpret("")
  
          assert interpret("os.name != 'buuuu'")
          assert interpret("os_name != 'buuuu'")
          assert interpret("python_version > '1.0'")
          assert interpret("python_version < '5.0'")
          assert interpret("python_version <= '5.0'")
          assert interpret("python_version >= '1.0'")
          assert interpret("'%s' in os.name" % os_name)
          assert interpret("'%s' in os_name" % os_name)
          assert interpret("'buuuu' not in os.name")
  
          assert not interpret("os.name == 'buuuu'")
          assert not interpret("os_name == 'buuuu'")
          assert not interpret("python_version < '1.0'")
          assert not interpret("python_version > '5.0'")
          assert not interpret("python_version >= '5.0'")
          assert not interpret("python_version <= '1.0'")
          assert not interpret("'%s' not in os.name" % os_name)
          assert not interpret("'buuuu' in os.name and python_version >= '5.0'")
          assert not interpret("'buuuu' in os_name and python_version >= '5.0'")
  
          environment = default_environment()
          environment['extra'] = 'test'
          assert interpret("extra == 'test'", environment)
          assert not interpret("extra == 'doc'", environment)
  
          def raises_nameError():
              try:
                  interpret("python.version == '42'")
              except NameError:
                  pass
              else:
                  raise Exception("Expected NameError")
  
          raises_nameError()
  
          def raises_syntaxError():
              try:
                  interpret("(x for x in (4,))")
              except SyntaxError:
                  pass
              else:
                  raise Exception("Expected SyntaxError")
  
          raises_syntaxError()
  
          statement = "python_version == '5'"
          assert compile(statement).__doc__ == statement
  
  
subject: Use simple assertions and pytest runner for test_markerlib.