diff --git a/test/Makefile.am.include b/test/Makefile.am.include
index 2b7ba75..addf2f9 100644
--- a/test/Makefile.am.include
+++ b/test/Makefile.am.include
@@ -35,7 +35,7 @@
 	%reldir%/mbox.c \
 	%reldir%/system.c
 
-TEST_MOCK_SRCS = %reldir%/backend.c $(TEST_MOCK_CORE)
+TEST_MOCK_SRCS = $(TEST_MOCK_CORE)
 
 test_get_mbox_info_v2_SOURCES = %reldir%/get_mbox_info_v2.c \
 				$(TEST_MBOX_SRCS) $(TEST_MOCK_SRCS)