WIP: Test plugins

[brendanlong]

[brendanlong]

I started on this but I can't get it to compile:

[ 79%] Building C object plugins/backend/feedbin/CMakeFiles/feedbin_test.dir/TestFeedbin.c.o
/home/blong/workspace/FeedReader/build/plugins/backend/feedbin/TestFeedbin.c:25:10: fatal error: TestPlugin.h: No such file or directory
 #include "TestPlugin.h"
          ^~~~~~~~~~~~~~
compilation terminated.
make[2]: *** [plugins/backend/feedbin/CMakeFiles/feedbin_test.dir/build.make:101: plugins/backend/feedbin/CMakeFiles/feedbin_test.dir/TestFeedbin.c.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:1264: plugins/backend/feedbin/CMakeFiles/feedbin_test.dir/all] Error 2
make: *** [Makefile:141: all] Error 2

I can't figure out what's wrong, since TestPlugin.h exists:

blong@blong-xps13:FeedReader[test-plugins]$ ls build/plugins/backend/test/
CMakeFiles           libTestPlugin.a  testplugin_target_valac.stamp
cmake_install.cmake  Makefile         TestPlugin_target_valac.stamp
CTestTestfile.cmake  TestPlugin.c     TestPlugin.vapi
libtestplugin.a      TestPlugin.h