Implementing Mock Repository for Unit Testing

[pemattern]

Summary

Hello, Im implementing unit testing in my axum application by mocking a database and testing the results from my handlers. I have a DatabaseRepository trait which allows me to swap out the real repository with mock repository. Now I have two options:

1. Use dynamic dispatch and incur a runtime cost just for the sake of unit testing
2. Use static dispatch and require trait bounds on all my handlers because my AppState has a type parameter

Is there a better way to do this? Or should I just add the trait bounds to all my handlers?

Thank you!

axum version

0.8.6

[yanns]

In my experience, I'm using the dynamic dispatch like this:

pub type DynDatabaseRepository = Box<dyn DatabaseRepository + Send + Sync>;

I use DynDatabaseRepository on my Environment struct.
And I put the Environment in the AppState.
I don't need any trait bounds on all handlers with that approach.

[pemattern]

Thank you 👍

[jplatte]

Use dynamic dispatch and incur a runtime cost just for the sake of unit testing

I don't think you should be worrying about the runtime cost of dynamic dispatch for something as slow as DB access, FWIW.

[pemattern]

Fair point, thanks