Document that using of macros like Q_ASSERT be avoided in auto tests

Document that using Q_ASSERT in unit tests should be avoided and demonstrate alternatives.

Using Q_ASSERT causes a test program to abort, resulting in incomplete/malformed test output and preventing remaining test functions in the test program from being executed. It is better to report a test failure using QVERIFY (which will skip the rest of the current test function) and allow the test program to continue executing.