diff --git a/tests/Makefile.am.inc b/tests/Makefile.am.inc
index 1c2b3723..d1d9e531 100644
--- a/tests/Makefile.am.inc
+++ b/tests/Makefile.am.inc
@@ -37,6 +37,7 @@ testcommon_CFLAGS = \
 	$(APPSTREAM_GLIB_CFLAGS) \
 	-DFLATPAK_COMPILATION \
 	-I$(srcdir)/app \
+	-I$(builddir)/app \
 	$(NULL)
 testcommon_LDADD = \
 	$(AM_LDADD) \