The test_suite/helpers directory has been renamed to test_suite/FGTestApi/ and
all the fgtest namespaces renamed to FGTestApi. The helper functions are now
also placed into either a setUp or tearDown namespace depending on their
function. And a new FGTestApi::PrivateAccessor::FDM namespace has been created
for holding friend classes used to access private or protected variables or
functions from solely within the test suite.
Some of the unit tests defined with the new test infrastructure[1]
initialize the QApplication; for these tests, it is necessary to ensure
that the QApplication instance is destroyed before exit() begins,
otherwise we get a segfault when run_test_suite terminates (see [2]).
In order to prevent this segfault from happening, call
flightgear::shutdownQtApp() unconditionally from
fgtest::shutdownTestGlobals() as long as Qt support is compiled in
(flightgear::shutdownQtApp() is safe to call even if the QApplication
hasn't been initialized).
[1] Currently, the three PosInitTests::* tests.
[2] https://bugreports.qt.io/browse/QTBUG-48709
The exceptions that occur after this call can be handled by CppUnit, but the
exit() results in the test suite silently exiting without restoring stdout and
stderr.
