This resolves a long-standing issue:
we could not use proper include paths for test-helper code that was defined alongside the tests.
Since some test-helper code must now be relocated into the »Vault«-Layer,
I took the opportunity to finally resolve this annoyance. The solution is two-fold
* introduce a dedicated test-support library
* remove the quirks that were necessary to support some plain-C tests
Together, this allows to raise the include-directory by one level,
and then to adjust all folder names so that they match the namespace
the buildsystem will now pick up and link
all test cases according to the layer, e.g.
backend tests will automatically be linked
against the backend + library solely.
Added some more fuzz and sleeping to the test calculation to have a actual
chance to fail when something is not well locked.
Using a premature classlock, locking instances was insufficient.
This removes the explicit Sync things from the thread wraper since
the functionality is almost exactly provided by the backend.
Thread encapsulates a lumiera thread handle now, but this is strictly
optional and might be dropped on the floor (using a temporary as thread).
Thread has a sync() function which allows user controlled syncronous
startup:
Thread("foo", myoperation).sync();
will startup myoperation and only return from the ctor after myoperation
called a matching lumiera_thread_sync().
The related tests need to initialize/destroy the threadpool accordingly
