run_tests.py wasn't actually running any tests.

[billpugh]

Fixing run_tests.py

run_tests.py wasn't actually causing any tests to run. This change fixes that, but it is worth examining why it had stopped working. Analysis performed and write-up up by Claude, reviewed by Bill Pugh

History of run_tests.py and Why It Broke

Original working version (commits b7281c4 and 092458c):

  import unittest
  from tests.test_parser import *

  if __name__ == '__main__':
      unittest.main()

How it worked:

• The from tests.test_parser import * line imported all test classes into the run_tests module's namespace
• When unittest.main() ran, it discovered tests in the current module (run_tests.py)
• Since the test classes were imported, they appeared to be defined in run_tests.py, so unittest.main() found and ran them

Broken version (commit 9d2363b - Feb 2024 "add pre-commit hooks"):

  import unittest

  if __name__ == "__main__":
      unittest.main()

What changed:

• The commit removed the from tests.test_parser import * line
• This was likely done by an auto-formatter (black or similar) during the pre-commit hooks setup
• Without the import, unittest.main() looks in the current module and finds nothing - hence 0 tests

Why it was removed:

• Using from X import * is considered bad practice (PEP 8 discourages it)
• The linter/formatter likely flagged it as a code smell
• The developer removed it to satisfy the linters but didn't realize it broke test discovery

The Fix:

The solution uses the proper unittest API for test discovery:

loader = unittest.TestLoader()
suite = loader.discover('tests')
runner = unittest.TextTestRunner(verbosity=2)
runner.run(suite)

This is the correct way to discover tests in a separate directory. It doesn't rely on namespace pollution from import *.

So yes, unittest.main() worked in the past, but only because of the from tests.test_parser import * hack. When that was removed for
code quality reasons, the test runner broke.

[nclarkjudd]

Merged in #61