docs/kola: mention external tests are preferred
All else equal, we prefer test contributors to use the external test
model where tests can live alongside the OS definition over adding more
"native" kola tests.
See previous discussions about this in
@@ -17,6 +17,18 @@ nav_order: 1
3. Edit the file and add your test(s), ensuring that you register your new test(s) in the packages `init()`
4. Commit, push, and PR your result
+## Relationship to external tests
+
+If your test can be run as an [external test](external-tests.md) (i.e. from a
+script which runs directly on the host), then that approach is preferred. Most
+likely, the test would live in the fedora-coreos-config repo (or if tightly
+coupled to a specific project, in that project's repo; there are plans to make
+those more consumable by FCOS/RHCOS).
+
+If your test needs richer information about e.g. the cosa build, or multiple
+nodes, or more support code from outside the test subject, then adding a
+native kola test as described here is a better fit.
+
### Example
Say we wanted to add a simple [noop](https://en.wikipedia.org/wiki/NOP_(code)) test in the `podman` test package. If we follow the above instructions it would look like this:
