speed up tests

[jstriebel]

CLI integration tests

Some of the CLI test scripts take quite long and should be sped up (by using a smaller test case, or by improving the routines if possible):

• compression_and_verification.sh 1m38s
• upsampling.sh 1m27s
• downsampling.sh 20s
• anisotropic_downsampling.sh 18s
• in_place_compression.sh 13s

unit tests

No unit test should take longer than 5s without very good reasons. I collected the slowest tests in wkcuber and webknossos using poetry run pytest --durations=0

wkcuber

34.52s call     tests/test_downsampling.py::test_compressed_downsample_cube_job
23.50s call     tests/test_downsampling.py::test_downsample_cube_job
6.57s call     tests/test_upsampling.py::test_compressed_upsample_cube_job
5.10s call     tests/test_upsampling.py::test_upsample_cube_job
4.43s call     tests/test_downsampling.py::test_downsample_mag_list

webknossos

6.84s call     tests/test_dataset.py::test_chunking_wk_advanced
3.30s call     tests/test_dataset.py::test_chunking_wk_wrong_chunk_size

[jstriebel]

related: #580

[jstriebel]

Besides reducing the test times per test, we might want to use pytest-xdist to parallelize the tests. This needs some work on using tmppath everywhere instead of the testoutput directory, to avoid conflicting parallel tests.