makefile unit test fix

makefile

@@ -35,7 +35,7 @@ $(program_obj_filesobj_files): %.o: %.c
 # --------------------------
 # Unit Tests
 # --------------------------
-unitTests: numbers.o test_numbers.c $(unityfolder)/unity.c
+unitTests: numbers.o test_numbers.c bintree.o $(unityfolder)/unity.c
 	$(CC) $(FLAGS) -I$(unityfolder) -o runtest_numbers test_numbers.c numbers.o bintree.o $(unityfolder)/unity.c
 
 # --------------------------