Right now the upload-wizard_test.py script doesn't add the category
"[[Category:Test images]]" to the images that are uploaded. The category was
added manually after running the script. This is suboptimal since users may
forget to add this category when they run the tests agains a different
environment or with a different user. The test should add this category
automatically as part of the actual uploading task. See:

https://bugzilla.wikimedia.org/show_bug.cgi?id=58914