diff --git a/Makefile b/Makefile
index dcebd2a..cc12346 100644
--- a/Makefile
+++ b/Makefile
@@ -23,4 +23,8 @@ install:
 
 uninstall:
 	rm -f ${DESTDIR}usr/bin/${TARGET}
-	rm -f ${DESTDIR}usr/share/licenses/${TARGET}/LICENSE
\ No newline at end of file
+	rm -f ${DESTDIR}usr/share/licenses/${TARGET}/LICENSE
+
+test:
+	@echo -n "Does input \"3.68 120 30d\" gives 317.95? "
+	@test "${shell ./kwh-cost 3.68 120 30d}" = "317.95" && { echo -e "\e[32mYES\e[0m"; } || { echo -e "\e[31mNO\e[0m"; }
\ No newline at end of file