diff --git a/Makefile b/Makefile
index 9e82b26d3..5c8de235b 100644
--- a/Makefile
+++ b/Makefile
@@ -95,7 +95,11 @@ test: lint unit-tests
 
 .PHONY: unit-tests
 unit-tests: devdeps
+ifdef TESTS
 	@$(PIPENV) run python3 -m unittest $(TESTS)
+else
+	@$(PIPENV) run python3 -m unittest discover -t . -s tests
+endif # TESTS
 
 reset-bootloader:
 	@echo "===> Rebooting your board to bootloader (safe to ignore file not found errors)"