Update CONTRIBUTING

.github/CONTRIBUTING.rst

@@ -8,11 +8,16 @@ overview of how we've set this project up.
 Testing
 -------
 
-Tests are run with `nox`_. See ``noxfile.py`` for the scaffolding and the
-``tests/unit`` and ``tests/integration`` folders for the actual test code.
+Tests are run with `nox`_. See each project's ``noxfile.py`` for the scaffolding
+and the ``tests/unit`` and ``tests/integration`` folders for the actual test
+code.
 
-You can get nox with ``pip install nox`` and run the project's tests with
-``nox``.
+You can get nox with ``pip install nox`` and run a specific project's tests with
+``nox -f <project-folder>/noxfile.py``.
+
+Some project are still part of the ``gcloud-rest`` package. We are working on 
+separating them but for now, run those projects' test together by running
+``nox``. The test scaffolding is in the root ``noxfile.py``.
 
 Local Development
 ~~~~~~~~~~~~~~~~~