add commands of how to run the test

Signed-off-by: Jim Lin <b04705003@ntu.edu.tw>

Author: jimlinntu

README.md

@@ -51,6 +51,18 @@ Run test:
 docker buildx bake test
 ```
 
+Run the unit test:
+
+```
+$ make -f docker.Makefile test-unit
+```
+
+Run the full test suite:
+
+```
+$ make -f docker.Makefile test
+```
+
 List all the available targets:
 
 ```shell