Sample for custom health indicator with spec

[openscript]

Is there an existing issue that is already proposing this?

• I have searched the existing issues

Is your feature request related to a problem? Please describe it

I have multiple custom health indicators. I should like to write some specs for the controllers, unfortunately it's tricky to mock the dependencies for this controllers.

Describe the solution you'd like

A sample with a custom health indicator and controller, including a spec, would help a lot.

Teachability, documentation, adoption, migration strategy

Maybe a section about testing can be added to the documentation.

What is the motivation / use case for changing the behavior?

Better testing is always welcome.