issues with os.path.exists

[lukesg08]

I have an assignment where students are using

os.path.exists

My setup is:

MAIN_REPORT.submission.files.update({"good_data.txt": file_contents})

However, when I try running the code through an assertion (which I don't think is actually relevant to the issue)

assert_equal(expected, call(func_name, "good_data.txt"))

The file path does not exist if the student uses

os.path.exists(filename)

the open function still works and works as if the file is there though. I believe this is because we just override the open function...but I'm not 100% sure