Nothing special or too sophisticated. On the one hand I use Just (a command runner) to standardize specific build and test commands that call cargo with various flags. Here is a simple example from one of my repos: https://github.com/deepmesa/deepmesa-rs/blob/mainline/justfi...
Then I have a bunch of elisp code that calls just and / or generates boilerplate code right in the buffer - M-x new-macro or M-x run-test (asks for a test to run) etc. I keep writing more elisp as I go along and add specific key bindings to specific things and now its too hard to move away from it all.
What kind of emacs scripts do you write to help debug Rust?