Rust: Unit tests in a separate file

In rust, tests are written in the same file as the code. But I want to have the tests in a separate file.

Conventionally, only the integration tests are written in files under tests folder. ¹

I just wanted to have the unit tests in a separate file. So I created a file src/my_tests.rs and moved all the tests there.

But cargo test kept saying running 0 tests

Turns out, I’m not the only one. ²

if you don’t import it in main then it doesn’t “exist” as far as the compiler’s concerned. ³

I was able to fix it by adding mod my_tests; to the top of main.rs

It is one thing to read the docs, but real learning comes from actually writing the code. (and making mistakes)