old_contents: #!/usr/bin/env python3
  import os
  import subprocess
  import sys
  
  
  args = [
      sys.executable or 'python',  # Python interpreter to call for testing.
      '-B',  # Don't write .pyc files on import.
      '-m', 'unittest', # Run the unittest module as a script.
      'discover',  # Use test discovery.
      '-s', 'tests',  # Start discovery in 'tests' directory.
      '-t', os.path.dirname(__file__),  # Set top-level of project.
  ]
  args.extend(sys.argv[1:])  # Append any arguments passed to script (-v, etc.).
  sys.exit(subprocess.call(args))
  
  
new_contents: #!/usr/bin/env python3
  import os
  import subprocess
  import sys
  
  
  args = [
      sys.executable or 'python',  # Python interpreter to call for testing.
      '-B',  # Don't write .pyc files on import.
      '-W', 'default',  # Enable default handling for all warnings.
      '-m', 'unittest', # Run the unittest module as a script.
      'discover',  # Use test discovery.
      '-s', 'tests',  # Start discovery in 'tests' directory.
      '-t', os.path.dirname(__file__),  # Set top-level of project.
  ]
  args.extend(sys.argv[1:])  # Append any arguments passed to script (-v, etc.).
  sys.exit(subprocess.call(args))
  
  
subject: Enable default warnings while testing.