The "check for updates" button wasn't showing up immediately as checked
as soon as the user is prompted for checking updates. This fixes that.
Fixes#513
Fully test the update check logic, by introducing several Qt tests.
Also, improve the `UpdaterThread.get_letest_info()` method, that gets
the latest version and changelog from GitHub, with several checks.
These checks are also tested in our newly added tests.
We want to differentiate between the user clicking on "Cancel" and
clicking on "X", since in the second case, we want to remind them again
on the next run.
Now that sample_doc was renamed to sample_pdf it could cause some
confusion the fact that that the TestBase class had an attribute called
sample_doc which referenced the sample PDF.
By removing this attribute and passing the fixture instead we are
following a more pytest-native approach of passing arguments explicitly.
Add a Pytest fixture that returns an UpdaterThread instance which has
its own unique settings directory. Note that the UpdaterThread instance
needs to be slightly nerfed, so that it doesn't rely on Qt functionality
or any isolation providers.
