diff --git a/Makefile b/Makefile
index e8a9d6f..53ed3f8 100644
--- a/Makefile
+++ b/Makefile
@@ -28,6 +28,12 @@ install: gcd/bin/gcd format_bytes/bin/format_bytes format_time/bin/format_time f
 uninstall:
 	@cd /usr/bin && rm -v compress convertUTF8 extract gcd format_bytes format_time format_time_ns
 
+.NOTPARALLEL:
+.PHONY: test
+test:
+	@(cd format_bytes && exec make -s test)
+	@(cd format_time && exec make -s test)
+
 .NOTPARALLEL:
 .PHONY: clean
 clean: