text: import abc
  import unittest
  
  
  class FinderTests(unittest.TestCase, metaclass=abc.ABCMeta):
  
      """Basic tests for a finder to pass."""
  
      @abc.abstractmethod
      def test_module(self):
          # Test importing a top-level module.
          pass
  
      @abc.abstractmethod
      def test_package(self):
          # Test importing a package.
          pass
  
      @abc.abstractmethod
      def test_module_in_package(self):
          # Test importing a module contained within a package.
          # A value for 'path' should be used if for a meta_path finder.
          pass
  
      @abc.abstractmethod
      def test_package_in_package(self):
          # Test importing a subpackage.
          # A value for 'path' should be used if for a meta_path finder.
          pass
  
      @abc.abstractmethod
      def test_package_over_module(self):
          # Test that packages are chosen over modules.
          pass
  
      @abc.abstractmethod
      def test_failure(self):
          # Test trying to find a module that cannot be handled.
          pass
  
  
  class LoaderTests(unittest.TestCase, metaclass=abc.ABCMeta):
  
      @abc.abstractmethod
      def test_module(self):
          """A module should load without issue.
  
          After the loader returns the module should be in sys.modules.
  
          Attributes to verify:
  
              * __file__
              * __loader__
              * __name__
              * No __path__
  
          """
          pass
  
      @abc.abstractmethod
      def test_package(self):
          """Loading a package should work.
  
          After the loader returns the module should be in sys.modules.
  
          Attributes to verify:
  
              * __name__
              * __file__
              * __package__
              * __path__
              * __loader__
  
          """
          pass
  
      @abc.abstractmethod
      def test_lacking_parent(self):
          """A loader should not be dependent on it's parent package being
          imported."""
          pass
  
      @abc.abstractmethod
      def test_module_reuse(self):
          """If a module is already in sys.modules, it should be reused."""
          pass
  
      @abc.abstractmethod
      def test_state_after_failure(self):
          """If a module is already in sys.modules and a reload fails
          (e.g. a SyntaxError), the module should be in the state it was before
          the reload began."""
          pass
  
      @abc.abstractmethod
      def test_unloadable(self):
          """Test ImportError is raised when the loader is asked to load a module
          it can't."""
          pass
  