diff --git a/firmware/test/makefile-vars b/firmware/test/makefile-vars
index e16b234145..15815e80ff 100644
--- a/firmware/test/makefile-vars
+++ b/firmware/test/makefile-vars
@@ -70,7 +70,7 @@ HEADERS = $(PACKAGE).h \
 	  inlines.h \
 	  functions.h
 
-SOURCES = $(PACKAGE).c
+SOURCES = $(wildcard $(PACKAGE)-$.c)
 
 OBJECTS  = $(SOURCES:.c=.o)