How to make submodules in integration test without mod.rs?

The book says,

/tests
/tests/target1.rs
/tests/common/mod.rs

to build a submodule common for target1.

And since Rust 2021, mod.rs is not a recommended practice.
And if I convert it to 2021 edition way,

/tests
/tests/target1.rs
/tests/common.rs

It simply becomes another target.
How am I supposed to make common submodule without mod.rs?

You can't. That's the reason why the book said so.

1 Like

You can do it, please have a look this repo for example.

There is no clear consensus about which of the two styles to prefer. See also modules: describe both module filename styles without giving a clear preference by RalfJung · Pull Request #1703 · rust-lang/reference · GitHub to reword the reference to not state that one is preferred over the other.