text: import pytest
  from _pytest.main import ExitCode
  
  
  def test_version(testdir, pytestconfig):
      result = testdir.runpytest("--version")
      assert result.ret == 0
      # p = py.path.local(py.__file__).dirpath()
      result.stderr.fnmatch_lines(
          ["*pytest*{}*imported from*".format(pytest.__version__)]
      )
      if pytestconfig.pluginmanager.list_plugin_distinfo():
          result.stderr.fnmatch_lines(["*setuptools registered plugins:", "*at*"])
  
  
  def test_help(testdir):
      result = testdir.runpytest("--help")
      assert result.ret == 0
      result.stdout.fnmatch_lines(
          """
          *-v*verbose*
          *setup.cfg*
          *minversion*
          *to see*markers*pytest --markers*
          *to see*fixtures*pytest --fixtures*
      """
      )
  
  
  def test_hookvalidation_unknown(testdir):
      testdir.makeconftest(
          """
          def pytest_hello(xyz):
              pass
      """
      )
      result = testdir.runpytest()
      assert result.ret != 0
      result.stdout.fnmatch_lines(["*unknown hook*pytest_hello*"])
  
  
  def test_hookvalidation_optional(testdir):
      testdir.makeconftest(
          """
          import pytest
          @pytest.hookimpl(optionalhook=True)
          def pytest_hello(xyz):
              pass
      """
      )
      result = testdir.runpytest()
      assert result.ret == ExitCode.NO_TESTS_COLLECTED
  
  
  def test_traceconfig(testdir):
      result = testdir.runpytest("--traceconfig")
      result.stdout.fnmatch_lines(["*using*pytest*py*", "*active plugins*"])
  
  
  def test_debug(testdir, monkeypatch):
      result = testdir.runpytest_subprocess("--debug")
      assert result.ret == ExitCode.NO_TESTS_COLLECTED
      p = testdir.tmpdir.join("pytestdebug.log")
      assert "pytest_sessionstart" in p.read()
  
  
  def test_PYTEST_DEBUG(testdir, monkeypatch):
      monkeypatch.setenv("PYTEST_DEBUG", "1")
      result = testdir.runpytest_subprocess()
      assert result.ret == ExitCode.NO_TESTS_COLLECTED
      result.stderr.fnmatch_lines(
          ["*pytest_plugin_registered*", "*manager*PluginManager*"]
      )
  