twisted.test.test_process.UtilTestCase should restore the rights of files it creates

[therve]

In particular, one of the "executable" file is read-only under windows, so that creates some problems. We can also delete the tree of files.

[therve]

Please review.

[exarkun]

Humm. I don't understand the motivation. Can you elaborate a bit?

[therve]

In particular, it prevents trial from cleaning _trial_temp. Running trial successively in the same directory leaves plenty of old _trial_temp (because the read-only file can't be removed without a user interaction). It also crash combinator mkbranch on my machine.

[exarkun]

trial seems to also use shutil.rmtree to get rid of old _trial_temp directories. I think I still don't understand, because it seems like the call to rmtree in test_process is just duplication of what trial is doing already.

[therve]

Hum good point. I'll investigate further.

[therve]

OK you were right, I don't know what I thought. The latest patch corrects the problem though.

[exarkun]

Looks good. Please apply.

Maybe we can also think about teaching trial to be super awesome at deleting things so individual tests don't have to think about it as much.

[therve]

(In [23444]) Fix twisted.test.test_process.UtilTestCase so that it doesn't leave read-only files in _trial_temp anymore.

Author: therve Reviewer: exarkun Fixes #3202

[exarkun]

(In [23447]) Revert r23444 - test suite regression on FreeBSD

Reopens: #3202

This changeset introduced three test failures on FreeBSD by way of an exception in the modified tearDown method:

===============================================================================
[ERROR]: twisted.test.test_process.UtilTestCase.testWhich

Traceback (most recent call last):
  File "/usr/home/therve/Run/slave/freebsd-py2.4-select/Twisted/twisted/test/test_process.py", line 1963, in tearDown
    os.chmod(os.path.join(self.bazbar, "executable"), 700)
exceptions.OSError: [Errno 79] Inappropriate file type or format: 'twisted.test.test_process/UtilTestCase/testWhich/lo3a1X/temp/baz/bar/executable'
===============================================================================
[ERROR]: twisted.test.test_process.UtilTestCase.testWhichPathExt

Traceback (most recent call last):
  File "/usr/home/therve/Run/slave/freebsd-py2.4-select/Twisted/twisted/test/test_process.py", line 1963, in tearDown
    os.chmod(os.path.join(self.bazbar, "executable"), 700)
exceptions.OSError: [Errno 79] Inappropriate file type or format: 'twisted.test.test_process/UtilTestCase/testWhichPathExt/VchWFn/temp/baz/bar/executable'
===============================================================================
[ERROR]: twisted.test.test_process.UtilTestCase.test_whichWithoutPATH

Traceback (most recent call last):
  File "/usr/home/therve/Run/slave/freebsd-py2.4-select/Twisted/twisted/test/test_process.py", line 1963, in tearDown
    os.chmod(os.path.join(self.bazbar, "executable"), 700)
exceptions.OSError: [Errno 79] Inappropriate file type or format: 'twisted.test.test_process/UtilTestCase/test_whichWithoutPATH/OHS-2j/temp/baz/bar/executable'
-------------------------------------------------------------------------------

[exarkun]

(In [23448]) Branching to 'test_process-perms-3202'

[exarkun]

Sorry I am a bad reviewer. I fixed the intent of the original patch in the branch, but now I'm not sure I understand the intent again. :) If I had a Windows machine I might be able to figure it out, but since I don't, can you give me a hint?

[therve]

I think I've explained it here:

In particular, it prevents trial from cleaning _trial_temp. Running trial successively in the same directory leaves plenty of old _trial_temp (because the read-only file can't be removed without a user interaction).

The failed function is shutil.rmtree in _setUpTestdir. This case was mainly obvious on windows.

[exarkun]

I'm probably not understanding something about Windows. Do you need write permission on a file to delete it on Windows? On Linux, you only need write permission on the directory it is in.

[therve]

Yes, you need write permission to delete a file on Windows.

[exarkun]

Okay. Amazing. Now the change makes sense. I adjusted tearDown to use S_IWUSR (and not set the file readable or executable as neither of those seems to be necessary for deletion) instead of an octal since that's a bit easier to read. Otherwise the change is basically the same as the original.

[therve]

Please merge.

[exarkun]

(In [23467]) Merge test_process-perms-3202

Author: exarkun Reviewer: therve Fixes: #3202

Restore write permission on a temporary directory created by the tests so that files in it can be deleted by trial when the next test run begins.