diff --git a/ref/makefile b/ref/makefile
index b1bbb2c..eded036 100644
--- a/ref/makefile
+++ b/ref/makefile
@@ -1,13 +1,13 @@
-.PHONY: all run format clean
+.PHONY: all run test format clean
 
 all: bin/uxn
 
 run: all
 	@ bin/uxn test.bin "Text from arg"
-
+test:
+	@ bin/uxn opc-test.bin
 format:
 	@ clang-format -i uxn.c
-
 clean:
 	@ rm -r -f bin
 
diff --git a/ref/opc-test.bin b/ref/opc-test.bin
new file mode 100644
index 0000000..3cb434d
Binary files /dev/null and b/ref/opc-test.bin differ