-OUTPUTS = $(addsuffix .output,$(TESTS))
-ERRORS = $(addsuffix .errors,$(TESTS))
-RESULTS = $(addsuffix .result,$(TESTS))
+OUTPUTS = $(addsuffix .output,$(TESTS) $(EXTRA_GRADES))
+ERRORS = $(addsuffix .errors,$(TESTS) $(EXTRA_GRADES))
+RESULTS = $(addsuffix .result,$(TESTS) $(EXTRA_GRADES))