How to fix “Attempted relative import in non-package” even with __init__.py

Question

I\'m trying to follow PEP 328, with the following directory structure:

pkg/
  __init__.py
  components/
    core.py
    __init__.py
  tests/
    core_test.py         


        

Answer 1

As Paolo said, we have 2 invocation methods:

1) python -m tests.core_test
2) python tests/core_test.py

One difference between them is sys.path[0] string. Since the interpret will search sys.path when doing import, we can do with tests/core_test.py:

if __name__ == '__main__':
    import sys
    from pathlib import Path
    sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
    from components import core
    

And more after this, we can run core_test.py with other methods:

cd tests
python core_test.py
python -m core_test
...

Note, py36 tested only.