Fix tests build

Author: lenemter

tests/lib/meson.build

@@ -1,4 +1,6 @@
 lib_test_sources = files(
+    meson.project_source_root() / 'lib' / 'CommonEnums.vala',
+    meson.project_source_root() / 'lib' / 'WindowManager.vala',
     meson.project_source_root() / 'lib' / 'Gestures' / 'Gesture.vala',
     meson.project_source_root() / 'lib' / 'Gestures' / 'GestureTarget.vala',
     meson.project_source_root() / 'lib' / 'Gestures' / 'PropertyTarget.vala',