BUG: IO unit test creates file at home directory

[chrispe]

• I have checked that this issue has not already been reported.
• I have confirmed this bug exists on the latest version of pandas.
• (optional) I have confirmed this bug exists on the master branch of pandas.

---

The unit test at pandas/tests/io/test_common.py produces a file using a hardcoded name as shown below:

filename = path_type("~/sometest")
with icom.get_handle(filename, "w") as handles:
  assert os.path.isabs(handles.handle.name)
  assert os.path.expanduser(filename) == handles.handle.name

Problem description

A developer may encounter an empty file "sometest" appearing in their home directory (after running pytest). If the developer is unaware of that, then it may raise some wrong security concerns on their side. Also, in the extreme scenario that the developer has a file at the exact same path, then its content may be replaced.

Expected Output

I would expect the file produced by the unit test to be temporary and get deleted afterwards. Also, that the filename is generated rather than hardcoded.

[lithomas1]

@chrispe Thanks for the bug report. I can confirm this on master that a sometest file is created in the home directory(I'm testing this on MacOS). I think we should at least check for the existence of a file before overwriting and for sure clean up the file after we're done. cc @twoertwein

[twoertwein]

That test should use:

import pandas._testing as tm

with tm.ensure_clean() as path:
    ....

[chrispe]

In this test case we want to ensure that the path is able to expand correctly (i.e. ~/ is converted to an absolute path to home directory) right? However, the tm.ensure_clean does not allow creating a temp file in a custom directory. Should we then try to expand its functionality or directly use the module of tempfile?

[twoertwein]

you are right! If that is the only place where a file in "~"needs to be cleaned up, I wouldn't extend tm.ensure_clean.

[chrispe]

By a quick look at the rest of the tests, it seems like this is the only hardcoded case. If you agree, I can continue with a PR to use the tempfile module for the file creation.

[twoertwein]

By a quick look at the rest of the tests, it seems like this is the only hardcoded case. If you agree, I can continue with a PR to use the tempfile module for the file creation.

Yes, please go ahead :)