diff --git a/doc/development/testing_guide/best_practices.md b/doc/development/testing_guide/best_practices.md
index 403edf187c93d05cd49ed7541be1ef90721d53e0..be19b1f674f44e452a4cabd272d2c70308a3864f 100644
--- a/doc/development/testing_guide/best_practices.md
+++ b/doc/development/testing_guide/best_practices.md
@@ -59,6 +59,7 @@ When using spring and guard together, use `SPRING=1 bundle exec guard` instead t
 - Try to follow the [Four-Phase Test](https://thoughtbot.com/blog/four-phase-test) pattern, using newlines
   to separate phases.
 - Use `Gitlab.config.gitlab.host` rather than hard coding `'localhost'`.
+- For literal URLs in tests, use `example.com`, `gitlab.example.com`. This will ensure that we do not utilize any real URLs.
 - Don't assert against the absolute value of a sequence-generated attribute (see
   [Gotchas](../gotchas.md#do-not-assert-against-the-absolute-value-of-a-sequence-generated-attribute)).
 - Avoid using `expect_any_instance_of` or `allow_any_instance_of` (see