Permission issues may cause some tests to fail

[tpitkanen]

At least the following tests may fail if the directory/file returned by tempfile aren't fully accessible by the current user:

• unit.test_general_functions.TestCoinc.test_coinc_returns_expected_output_if_parameters_are_ok
• unit.test_general_functions.TestCoinc.test_output_is_written_to_file_if_output_file_is_given
• unit.test_get_espe.TestGetEspeRun.test_get_espe_run_returns_expected_spectrum
• unit.test_get_espe.TestGetEspeRun.test_get_espe_writes_results_to_given_spectrum_file

Reported on revision 8707dc7, Python 3.6.8 on Windows. The revision also features a failing test that was fixed in 50f9dc4.

(Issue originally reported in private correspondence with @jkpnen and @aleekaup2)

[tpitkanen]

The issue occured on a JYU-supplied Windows laptop. It is caused by (too) strict permissions to the %temp% directory.

The listed tests save input and output files for C programs in %temp%. The files are normally saved in a request's directory which means normal Potku usage is unaffected.

I could not reproduce the issue on my personal Windows devices or on JYU's macOS laptop.

As this is a development environment issue and not a Potku issue, it doesn't necessarily require changes to the tests/code. However, it is a good idea to note it in the documentation to prevent confusion among future developers.