Make our test cases write gimpdir files in a dedicate output directory
by changing GIMP2_DIRECTORY at runtime. This ends the writing to the
source directory which make distcheck doesn't like, and it also allows
us to have a separate expected sessionrc for the session management
test. In that test we load a GIMP 2.6 formated sessionrc but write one
updated for 2.8.
We perform this change by passing the builddir through an environment
variable to the test cases. The patch also does some generalizations
in gimp-app-test-utils.c and adapts test cases accordingly.
Also do an adjustment in sessionrc on the toolbox size since
GIMP/GTK+/X/whatever has a tendency to adjust that during runs. The
new size is stable for the moment.
Let each test sets GIMP2_DIRECTORY on their own through the help of a
new test utility function gimp_test_utils_set_gimp2_directory() that
is compiled into its own lib which tests are then linked with. Also,
instead of using "/tmp/gimpdir", we use "gimpdir-empty" in the source
dir. This way we get rid of a bunch of annoying warnings when running
the tests and have more control.
* tests.[ch]: initialize base so we have a tile cache and add
parameter "gboolean use_cpu_accel" so we can test stuff both with
and without using CPU features.
* tests/test-layer-grouping.c: changed accordingly. Call g_thread_init()
so the tile cache works (and to be on the safe side in general).
Enable us to have regression testing by introducing a core testing
framework that uses the GLib JUnit-like test library.
Do this by adding a new subdir app/tests that will contain all our
tests (it contains one trivial test already). Also add app/tests.[ch]
with a new function gimp_init_for_testing() so that test cases can
easily setup the core object system.
