Unify the many copies of diff_with_file in one source
file, and patch it to detect diff at runtime and fall
back to a simple strcmp if we don't have it. Make all
tests use this new testutils.c, and stop requiring
diff for building the tests.
This should let us allow to build on Windows with the
default value for -Dbuild-tests.
It it hard to control which of the csd style classes we get,
since it depends on details of the X server or compositor.
Explicitly ignore this difference by replacing .solid-csd
with .csd in the output.
Properly handle diff(1) failing.
In this particular case, the test passed a NULL input file to the diff
(that was fixed, too) and then diff only found one input file and
aborted.
But without this fix, we'd also not catch other abortion reasons for
diff() - as long as it exited in any way, we were happy.
Use a custom, empty theme and stop importing reset-to-defaults.css.
This avoids overwriting initial values, so our initial value
filtering works better.
This uses the same function for dumping CSS nodes and styles
as the CSS node test. It can be used to test aspects of inheritance
and matching, as well as initial values.
No actual tests yet.
