Bash completion to autocomplete all python tests within current project (using pytest)

gistfile1.txt

# This will allow to autocomplete tests in Terminal like this:
$ pytest tests/test_user_management.py::[TAB]
$ pytest tests/test_user_management.py::TestUserManagement[TAB]
$ pytest tests/test_user_management.py::TestUserManagement::test_user_create

# Add command writing fully qualified names of all test functions to a file
# conftest.py:
def pytest_addoption(parser):
    parser.addoption(
        "--collect-tests",
        action="store_true",
        help="Collect tests",
        default=False,
    )


def pytest_collection_modifyitems(config, items):
    tests = set()
    if config.option.collect_tests:
        for item in items:
            # filename::test_class[optional]::test_function
            path = os.path.relpath(item.module.__file__)
            item.add_marker(pytest.mark.skipif(True, reason="Skip"))
            tests.add("{}\n".format(path))
            test_str = path
            if item.cls:
                test_str += f"::{item.cls.__name__}"
            if item.function:
                test_str += f"::{item.function.__name__}"
            tests.add(f"{test_str}\n")
        with open(".pytest.completion", "w") as file:
            file.writelines(tests)


# Bash completion script
# If there is a .pytest.completion within current dir, 
# all its tests will be collected and provided to Bash completion
# /etc/bash_completion.d/pytest.completion

_pytest () {  
  local cur
  _get_comp_words_by_ref -n : cur
  if [ -f ".pytest.completion" ]; then
    COMPREPLY=( $( compgen -W '$(cat ".pytest.completion" | tr "\n" " ")' -- "$cur" ) )
    __ltrim_colon_completions "$cur"
  fi
}
complete -F _pytest pytest