old_contents: """develop tests
  """
  import os
  import re
  
  import pytest
  
  from setuptools.dist import Distribution
  
  from . import contexts
  
  SETUP_PY = """\
  from setuptools import setup
  
  setup(name='foo', py_modules=['hi'])
  """
  
  
  @pytest.yield_fixture
  def setup_context(tmpdir):
      with (tmpdir / 'setup.py').open('w') as f:
          f.write(SETUP_PY)
      with (tmpdir / 'hi.py').open('w') as f:
          f.write('1\n')
      with tmpdir.as_cwd():
          yield tmpdir
  
  
  class Test:
      def test_bdist_egg(self, setup_context, user_override):
          dist = Distribution(dict(
              script_name='setup.py',
              script_args=['bdist_egg'],
              name='foo',
              py_modules=['hi']
          ))
          os.makedirs(os.path.join('build', 'src'))
          with contexts.quiet():
              dist.parse_command_line()
              dist.run_commands()
  
          # let's see if we got our egg link at the right place
          [content] = os.listdir('dist')
          assert re.match(r'foo-0.0.0-py[23].\d.egg$', content)
  
new_contents: """develop tests
  """
  import os
  import re
  import zipfile
  
  import pytest
  
  from setuptools.dist import Distribution
  
  from . import contexts
  
  SETUP_PY = """\
  from setuptools import setup
  
  setup(name='foo', py_modules=['hi'])
  """
  
  
  @pytest.fixture(scope='function')
  def setup_context(tmpdir):
      with (tmpdir / 'setup.py').open('w') as f:
          f.write(SETUP_PY)
      with (tmpdir / 'hi.py').open('w') as f:
          f.write('1\n')
      with tmpdir.as_cwd():
          yield tmpdir
  
  
  class Test:
      def test_bdist_egg(self, setup_context, user_override):
          dist = Distribution(dict(
              script_name='setup.py',
              script_args=['bdist_egg'],
              name='foo',
              py_modules=['hi'],
          ))
          os.makedirs(os.path.join('build', 'src'))
          with contexts.quiet():
              dist.parse_command_line()
              dist.run_commands()
  
          # let's see if we got our egg link at the right place
          [content] = os.listdir('dist')
          assert re.match(r'foo-0.0.0-py[23].\d.egg$', content)
  
      def test_exclude_source_files(self, setup_context, user_override):
          dist = Distribution(dict(
              script_name='setup.py',
              script_args=['bdist_egg', '--exclude-source-files'],
              name='foo',
              py_modules=['hi'],
          ))
          with contexts.quiet():
              dist.parse_command_line()
              dist.run_commands()
          [dist_name] = os.listdir('dist')
          dist_filename = os.path.join('dist', dist_name)
          zip = zipfile.ZipFile(dist_filename)
          names = list(zi.filename for zi in zip.filelist)
          assert 'hi.pyc' in names
          assert 'hi.py' not in names
  
subject: Add test capturing expectation. Ref #1145.