docs: document how to run a quick crater e2e test

service-catalog/crater/README.md

@@ -50,6 +50,7 @@ And the bot will reply to you.
 ## How-to Guides
 
 [How to update Crater](./how-to-update-crater.md)
+[How to test Crater](./how-to-test-crater.md)
 
 [crater.rust-lang.org]: https://crater.rust-lang.org
 [rust-lang/crater]: https://github.com/rust-lang/crater

service-catalog/crater/how-to-test-crater.md

@@ -0,0 +1,17 @@
+# How to test crater
+
+After you do infra changes to crater, you might want to run a quick e2e test, to
+make sure everything continues working as expected.
+
+For an in-depth guide on how to use the crater bot from the `rust-lang/rust` repository,
+check the [bot-usage](https://github.com/rust-lang/crater/blob/master/docs/bot-usage.md)
+document.
+However, if you want to run a quick test, here's how to do it:
+
+1. Identify a PR where the bors testing succeeded
+   (e.g. [this](https://github.com/rust-lang/rust/pull/131362#issuecomment-2421811741))
+2. Comment on the PR with the following command:
+   ```
+   @craterbot run mode=check-only crates=https://gist.githubusercontent.com/MarcoIeni/3800cdca02ddb30ac98404cafa849c1b/raw/crates start=master#<start_commit> end=try#<end_commit>
+   ```
+   E.g. [this](https://github.com/rust-lang/rust/pull/131362#issuecomment-2435412130)