change Makefile

code/Makefile

@@ -7,8 +7,7 @@ run: $(TEST_RUN)
 
 %_test.run: %_test
 	@echo Testing $<...
-	@./$<
-	@echo OK
+	@(./$< && echo OK) || echo FAIL
 
 %_test: %_test.cpp %.cpp
 	@echo Compiling $@...