Auto tests in Qt have been written with various flavours of qtestlib, with the same test functions mixing several styles. Subsequent tests are frequently added by copy-and-paste from other tests, including bad practices. Over the years this have resulted in non-optimal and flakey tests. Create a section in docs on common patterns and good practices. This page later could easily be extended when discovering other anti-patterns found during fixing flakey and other odd looking tests.
Reduce fragmentation by merging https://wiki.qt.io/Unit_Testing and https://wiki.qt.io/Writing_Unit_Tests into this official documentation. Wiki pages is a lazy way of documenting things properly. Note: the contents of these wiki pages needs to be evaluated when moving to the official documentation.
There should also be a subsection on debugging techniques. See https://codereview.qt-project.org/#/c/208303/5/src/testlib/qtesthelpers_p.h for an example of what this section could contain.
End result of this task would be a single point of a reference for new contributions of tests.