Add test_roi_thumbnails()

[will-moore]

Adds tests for ome/omero-web#157
Tests fail without that PR

[will-moore]

Removed last commit (flake8 fix) since it's been ported to a separate PR #6236

[joshmoore]

Re-opening with #6236 merged.

[will-moore]

Yes, I tried import rgba_to_int from test_api_rois before (see 46c37f8) but for some reason this import fails:

$ pytest test/integration/test_thumbnails.py 
======================================================================= test session starts =======================================================================
platform darwin -- Python 3.6.10, pytest-5.3.4, py-1.8.1, pluggy-0.13.1
django: settings: omeroweb.settings (from ini)
rootdir: /Users/wmoore/Desktop/OMERO/openmicroscopy/components/tools, inifile: pytest.ini
plugins: forked-1.1.3, django-3.8.0
collected 0 items / 1 error                                                                                                                                       

============================================================================= ERRORS ==============================================================================
__________________________________________________ ERROR collecting OmeroWeb/test/integration/test_thumbnails.py __________________________________________________
ImportError while importing test module '/Users/wmoore/Desktop/OMERO/openmicroscopy/components/tools/OmeroWeb/test/integration/test_thumbnails.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
test/integration/test_thumbnails.py:32: in <module>
    from test_api_rois import rgba_to_int
E   ModuleNotFoundError: No module named 'test_api_rois'

although I'm also getting similar import errors on other tests, so I've got something wrong locally.

[jburel]

rgba_to_int the method could go in a test lib package since it used by the tests

[jburel]

Thanks for the first round of changes. As mentioned above the method needs to be moved to a common file

[jburel]

where is that size defined?

[will-moore]

width defined at https://github.com/ome/omero-web/blob/ec07fe59bf3af6ae002d634675d59a4b0b679b18/omeroweb/webgateway/views.py#L495

and height defined at https://github.com/ome/omero-web/blob/ec07fe59bf3af6ae002d634675d59a4b0b679b18/omeroweb/webgateway/views.py#L574

[joshmoore]

Might be worth extracting such magic numbers out to a constant somewhere (at some point in the future)

[jburel]

Looking at the various methods to generate thumbnails.
I noticed that the IO resources are not closed in the method implementation.
So this is a good time to tackle that problem and see if the tests remain green

[will-moore]

Closed BytesIO in webgateway get_shape_thumbnail() in ome/omero-web@e2fc30c

[joshmoore]

https://merge-ci.openmicroscopy.org/jenkins/job/OMERO-test-integration/428/testReport/OmeroWeb.test.integration.test_thumbnails/ is now green. 👍