Document Drupal Development Env: composer/plugin/drupal-development-environment#1

docs/dev_tools/test.md

@@ -221,8 +221,26 @@ Now all you need is installed and set up. Execute the following command to run t
 a test stylelintmodule <contrib_module>
 ```
 
+If you want to analyse a custom module, just do the following:
+
+```style
+a test stylelintmodule ../custom/<custom_module>
+```
+
 ### ES Lint
 
+This is another useful tool to test your `css` files.
+
+```eslint
+a test eslintmodule <contrib_module>
+```
+
+If you want to analyse a custom module, just do the following:
+
+```eslint
+a test eslintmodule ../custom/<custom_module>
+```
+
 ## Unit/Kernel/Functional Testing
 
 To execute the tests, you can use a single command: