diff --git a/tests/Makefile.include b/tests/Makefile.include
index 42fd426cd002..412aed1737f6 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -929,14 +929,14 @@ $(patsubst %, check-%, $(check-qapi-schema-y)): check-%.json: $(SRC_PATH)/%.json
 		$^ >$*.test.out 2>$*.test.err; \
 		echo $$? >$*.test.exit, \
 		"TEST","$*.out")
-	@diff $(SRC_PATH)/$*.out $*.test.out
 	@# Sanitize error messages (make them independent of build directory)
-	@perl -p -e 's|\Q$(SRC_PATH)\E/||g' $*.test.err | diff $(SRC_PATH)/$*.err -
-	@diff $(SRC_PATH)/$*.exit $*.test.exit
+	@perl -p -e 's|\Q$(SRC_PATH)\E/||g' $*.test.err | diff -u $(SRC_PATH)/$*.err -
+	@diff -u $(SRC_PATH)/$*.out $*.test.out
+	@diff -u $(SRC_PATH)/$*.exit $*.test.exit
 
 .PHONY: check-tests/qapi-schema/doc-good.texi
 check-tests/qapi-schema/doc-good.texi: tests/qapi-schema/doc-good.test.texi
-	@diff -q $(SRC_PATH)/tests/qapi-schema/doc-good.texi $<
+	@diff -u $(SRC_PATH)/tests/qapi-schema/doc-good.texi $<
 
 .PHONY: check-decodetree
 check-decodetree: