@ticky @Gyro
Hmm, you've read this article already, right? I haven't heard anything back from my social circles, but this one seems to be the most explicit about the topic?
https://users.rust-lang.org/t/artisanal-mocks-locally-sourced-organic-unit-tests/5890

For "a function someone else has already implemented", you might want to try something like this from the article?
pub mod db_client {
#[cfg(not(test))]
pub use super::db_client_concrete::*;

#[cfg(test)]
pub use tests::mocks::db_client::*;
}

except changed to refer to the foreign code, instead of your own "true" personal implementation?

nother toot coming along cuz i'm out of chars