A change in test_glob of issue #13968 started to fail because a previous test created temporary files but didn't remove them.

test.regrtest should at least emit a warning if the temporary directory used to run tests is not empty before removing it.

Here is a patch. It warns if new files or directories are left after test run in current directory and removes those of them which starts with TESTFN (i.e. TESTFN_UNICODE, TESTFN + "2", TESTFN + ".py" and other names used in tests).

I would prefer to fix tests instead of trying to remove arbitrary files. I'm not sure that "fn.startswith(support.TESTFN)" check is safe enough.

Maybe we should not remove TESTFN neither. You are supposed to be able to run tests without regrtest.

I ran the test suite with the patch applied:

7 tests altered the execution environment:
    test_imp test_import test_pdb test_posix test_source_encoding
    test_support test_threaded_import

I will try to investigate these warnings.

> I would prefer to fix tests instead of trying to remove arbitrary files. I'm
> not sure that "fn.startswith(support.TESTFN)" check is safe enough.

This allow other tests which leaks the same file to be reported too.

support.TESTFN contains process ID so it is unique enough.

> I will try to investigate these warnings.

Run tests with the -vv option.

fix_tests.patch: Fix the 7 tests which create files without removing them. 4 tests (test_imp, test_pdb, test_source_encoding and test_support) create a __pycache__ directory. Maybe this directory should be ignored by regrtest?

New changeset 8cf8bff3569e by Victor Stinner in branch '3.4':
Issue #22390: Remove files created by tests
https://hg.python.org/cpython/rev/8cf8bff3569e

How about regrtest_warn_lost_files.patch?

> This allow other tests which leaks the same file to be reported too.

I don't understand your answer. The "fn.startswith(support.TESTFN)" test is not used in get_files().

If I understood correctly, your patch changes two things:

- it now reports files created for tests but not deleted (purpose of this issue)
- it removes more files than before

I don't understand why you want to remove more files than before. You may open a different issue, or at least explain the rationale.

I never see any forgotten test file after running tests, so I don't see why you are worried because of them. And with your first patch, we will now noticed forgotten files, so we can just fix tests.

> I don't understand why you want to remove more files than before. You may
> open a different issue, or at least explain the rationale.

I thought it would be good idea slightly extend this cleanup while we are 
here. I'm not motivated enough to open a different issue.

Well, here is a patch which removes only TESTFN. It is still improved, uses 
support.unlink and support.rmtree instead of os.unlink and shutil.rmtree.

You can just drop cleanup code at all if you prefer. All is good to me.

> I never see any forgotten test file after running tests, so I don't see why
> you are worried because of them.

This is because regrtest creates temporary directory and goes to it. But when 
you execute Python test directly, test files are created in the current 
directory.

> And with your first patch, we will now
> noticed forgotten files, so we can just fix tests.

But we will noticed only one about test at the time if several tests forgot 
the same file. This will needed several iterations.

What about this issue?

Victor?

regrtest_warn_lost_files2.patch looks good to me.

I just ran the test suite with "./python -m test -j0 -rW" on Linux, I didn't get any warning.

When I modified test_os to create a file "x", it was noticed by your patch.

Go ahead.

New changeset f40984e7ceea by Serhiy Storchaka in branch '2.7':
Issue #22390: test.regrtest now emits a warning if temporary files or
https://hg.python.org/cpython/rev/f40984e7ceea

New changeset 05e6bab4db8f by Serhiy Storchaka in branch '3.4':
Issue #22390: test.regrtest now emits a warning if temporary files or
https://hg.python.org/cpython/rev/05e6bab4db8f

New changeset bed806c9eb4c by Serhiy Storchaka in branch 'default':
Issue #22390: test.regrtest now emits a warning if temporary files or
https://hg.python.org/cpython/rev/bed806c9eb4c

New changeset 207db4338706 by Victor Stinner in branch '2.7':
Issue #22390: Fix typo in regrtest, support => test_support
https://hg.python.org/cpython/rev/207db4338706

New changeset fb5c3528d0d7 by Victor Stinner in branch '2.7':
Issue #22390: Fix test_aifc to remove the created file
https://hg.python.org/cpython/rev/fb5c3528d0d7

New changeset c5c31adbefeb by Victor Stinner in branch '2.7':
Issue #22390: Fix test_pdb to remove created bar.pyc file
https://hg.python.org/cpython/rev/c5c31adbefeb

New changeset 33e48141d83f by Victor Stinner in branch '2.7':
Issue #22390: Fix test_gzip, remove temporary file
https://hg.python.org/cpython/rev/33e48141d83f

On Windows, test_idle modifies os.environ: TCL_xxx and TIX_xxx (sorry
for "xxx", I don't remember the full variable name) are added. And
test_platform modifies os.environ['PATH'].

New changeset 6ef2cacec2e9 by Victor Stinner in branch '2.7':
Issue #22390: Fix test_gzip if unicode filename doesn't work
https://hg.python.org/cpython/rev/6ef2cacec2e9

Thank you for fixing backported patch and tests Victor.

Serhiy Storchaka added the comment:
> Thank you for fixing backported patch and tests Victor.

No problem, thanks for your enhancement of regrtest ;-) I proposed the
idea and you implemented it, great team work!