Where should I put test utility functions in Rust?

Question

I have the following code defining a path where generated files can be placed:

fn gen_test_dir() -> tempdir::TempDir {                                             


        

Answer 1

What I do is put my unit tests with any other utilities into a submodule protected with #[cfg(test)]:

#[cfg(test)]
mod tests {  // The contents could be a separate file if it helps organisation
    // Not a test, but available to tests.
    fn some_utility(s: String) -> u32 {
        ...
    }

    #[test]
    fn test_foo() {
        assert_eq!(...);
    }
    // more tests
}