Tests failures because of logging changes in Qt

[ghisvail]

Forwarded from Debian-Bug#872992.

The TL;DR is that testing with Qt 5.9 fails because of a change in the logging. The reporter solved this by exporting QT_LOGGING_RULES="default.debug=true" prior to running the tests.

[nicoddemus]

Thanks for the report @ghisvail.

From what I can understand this affects pytest-qt's own test suite only.

I wonder if setting the environment variable QT_LOGGING_RULES before running the tests but after Qt is imported solves this; this way we could easily create an autouse fixture for pytest-qt's test suite which sets this environment variable automatically.