text: """Test cases for the command line.
  
  To begin we test that "mypy <directory>[/]" always recurses down the
  whole tree.
  """
  
  import os
  import re
  import subprocess
  import sys
  
  from typing import List
  from typing import Optional
  
  from mypy.test.config import test_temp_dir, PREFIX
  from mypy.test.data import DataDrivenTestCase, DataSuite
  from mypy.test.helpers import (
      assert_string_arrays_equal, normalize_error_messages, check_test_output_files
  )
  
  try:
      import lxml  # type: ignore
  except ImportError:
      lxml = None
  
  import pytest
  
  # Path to Python 3 interpreter
  python3_path = sys.executable
  
  # Files containing test case descriptions.
  cmdline_files = [
      'cmdline.test',
      'cmdline.pyproject.test',
      'reports.test',
      'envvars.test',
  ]
  
  
  class PythonCmdlineSuite(DataSuite):
      files = cmdline_files
      native_sep = True
  
      def run_case(self, testcase: DataDrivenTestCase) -> None:
          if lxml is None and os.path.basename(testcase.file) == 'reports.test':
              pytest.skip("Cannot import lxml. Is it installed?")
          for step in [1] + sorted(testcase.output2):
              test_python_cmdline(testcase, step)
  
  
  def test_python_cmdline(testcase: DataDrivenTestCase, step: int) -> None:
      assert testcase.old_cwd is not None, "test was not properly set up"
      # Write the program to a file.
      program = '_program.py'
      program_path = os.path.join(test_temp_dir, program)
      with open(program_path, 'w', encoding='utf8') as file:
          for s in testcase.input:
              file.write(f'{s}\n')
      args = parse_args(testcase.input[0])
      custom_cwd = parse_cwd(testcase.input[1]) if len(testcase.input) > 1 else None
      args.append('--show-traceback')
      if '--error-summary' not in args:
          args.append('--no-error-summary')
      # Type check the program.
      fixed = [python3_path, '-m', 'mypy']
      env = os.environ.copy()
      env.pop('COLUMNS', None)
      extra_path = os.path.join(os.path.abspath(test_temp_dir), 'pypath')
      env['PYTHONPATH'] = PREFIX
      if os.path.isdir(extra_path):
          env['PYTHONPATH'] += os.pathsep + extra_path
      process = subprocess.Popen(fixed + args,
                                 stdout=subprocess.PIPE,
                                 stderr=subprocess.PIPE,
                                 cwd=os.path.join(
                                     test_temp_dir,
                                     custom_cwd or ""
                                     ),
                                 env=env)
      outb, errb = process.communicate()
      result = process.returncode
      # Split output into lines.
      out = [s.rstrip('\n\r') for s in str(outb, 'utf8').splitlines()]
      err = [s.rstrip('\n\r') for s in str(errb, 'utf8').splitlines()]
  
      if "PYCHARM_HOSTED" in os.environ:
          for pos, line in enumerate(err):
              if line.startswith('pydev debugger: '):
                  # Delete the attaching debugger message itself, plus the extra newline added.
                  del err[pos:pos + 2]
                  break
  
      # Remove temp file.
      os.remove(program_path)
      # Compare actual output to expected.
      if testcase.output_files:
          # Ignore stdout, but we insist on empty stderr and zero status.
          if err or result:
              raise AssertionError(
                  'Expected zero status and empty stderr%s, got %d and\n%s' %
                  (' on step %d' % step if testcase.output2 else '',
                   result, '\n'.join(err + out)))
          check_test_output_files(testcase, step)
      else:
          if testcase.normalize_output:
              out = normalize_error_messages(err + out)
          obvious_result = 1 if out else 0
          if obvious_result != result:
              out.append(f'== Return code: {result}')
          expected_out = testcase.output if step == 1 else testcase.output2[step]
          # Strip "tmp/" out of the test so that # E: works...
          expected_out = [s.replace("tmp" + os.sep, "") for s in expected_out]
          assert_string_arrays_equal(expected_out, out,
                                     'Invalid output ({}, line {}){}'.format(
                                         testcase.file, testcase.line,
                                         ' on step %d' % step if testcase.output2 else ''))
  
  
  def parse_args(line: str) -> List[str]:
      """Parse the first line of the program for the command line.
  
      This should have the form
  
        # cmd: mypy <options>
  
      For example:
  
        # cmd: mypy pkg/
      """
      m = re.match('# cmd: mypy (.*)$', line)
      if not m:
          return []  # No args; mypy will spit out an error.
      return m.group(1).split()
  
  
  def parse_cwd(line: str) -> Optional[str]:
      """Parse the second line of the program for the command line.
  
      This should have the form
  
        # cwd: <directory>
  
      For example:
  
        # cwd: main/subdir
      """
      m = re.match('# cwd: (.*)$', line)
      return m.group(1) if m else None
  