diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 939e5341..73aef19e 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -22,6 +22,23 @@ use GitHub pull requests for this purpose. Consult
 [GitHub Help](https://help.github.com/articles/about-pull-requests/) for more
 information on using pull requests.
 
+### Testing
+
+You can locally test using [`tox`](https://tox.wiki/).
+
+Unit tests:
+
+```
+python -m tox -e py38-ubuntu-latest 
+python -m tox -e lint
+```
+
+Lint:
+
+```
+.tox/lint/bin/black tests
+```
+
 ## Community Guidelines
 
 This project follows [Google's Open Source Community