diff --git a/build/core/definitions.mk b/build/core/definitions.mk
index f139aea..92ed684 100644
--- a/build/core/definitions.mk
+++ b/build/core/definitions.mk
@@ -1271,6 +1271,7 @@
     ))
 
 -test-get-object-name = \
+  $(eval TARGET_OBJ_EXTENSION=.o)\
   $(eval LOCAL_CPP_EXTENSION ?= .cpp)\
   $(call test-expect,foo.o,$(call get-object-name,foo.c))\
   $(call test-expect,bar.o,$(call get-object-name,bar.s))\