How to run a pytest test function on all data files in a folder

Question

I have a set of functions that I am attempting to write pytest unit tests for. The function I am trying to write a test for looks like so:

def IndexLevel(df: pd.DataFrame, index_row: str, start_col: str, end_col: str) -> pd.DataFrame:

    # Editing df
    return df_index

And the pytest function looks like so (df_format_index is a fixture to test df_index shape):

@pytest.mark.parametrize(
    "df, index_row, start_col, end_col, df_format_index",
    [(function("blah.txt"), "index level", "index level", "Equity 2", df_format_index)],
    indirect=["df_format_index"],
)
def test_IndexLevel(df: pd.DataFrame, index_row: str, start_col: str, end_col: str, df_format_index: pd.DataFrame):
    print("-----test-IndexLevel------")
    assert (IndexLevel(df: pd.DataFrame, index_row, start_col, end_col).shape == df_format_index.shape)

These functions work if I hard code the filename, but I would like to thoroughly test them by running the test on all data files in a folder. I have tried to use the following function, but it did not work:

def pytest_generate_tests(metafunc):
    filelist = glob.glob("Data/*.txt")
    metafunc.parametrize("filename", filelist)

How can I run the test on all files in the data folder without editing the original function?