docs: update documentation and improve testing instructions (#182)

- Add a section on testing with instructions to run `make test` in the README.md

ref: #181 

Signed-off-by: Bo-Yi Wu <[email protected]>

Author: appleboy

README.md

@@ -450,6 +450,14 @@ Suggestions for improvement:
 ==================================================
 ```
 
+## Testing
+
+Run the following command to test the code:
+
+```sh
+make test
+```
+
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