Welcome to Software Development on Codidact!
Will you help us build our independent community of developers helping developers? We're small and trying to grow. We welcome questions about all aspects of software development, from design to code to QA and more. Got questions? Got answers? Got code you'd like someone to review? Please join us.
Post History
Grouping related items into modules is of course generally good practice, but it serves a practical purpose as well. The important part here is the #[cfg(test)] annotation. The #[cfg(test)] anno...
Answer
#2: Post edited
by
Moshi
·
2023-08-06T02:10:23Z (9 months ago)
The important part here is the [`#[cfg(test)]` annotation](https://doc.rust-lang.org/book/ch11-03-test-organization.html#the-tests-module-and-cfgtest).- > The `#[cfg(test)]` annotation on the tests module tells Rust to compile and run the test code only when you run `cargo test`, not when you run `cargo build`. This saves compile time when you only want to build the library and saves space in the resulting compiled artifact because the tests are not included. You’ll see that because integration tests go in a different directory, they don’t need the `#[cfg(test)]` annotation. However, because unit tests go in the same files as the code, you’ll use `#[cfg(test)]` to specify that they shouldn’t be included in the compiled result.
- As it says, it is just a way to separate tests from the library itself; the other way is to use a separate directory.
Creating tests outside of such a module actually does work, though from the wording I would assume doing so would have the test end up in the resulting binary, which may be undesirable.
- Grouping related items into modules is of course generally good practice, but it serves a practical purpose as well. The important part here is the [`#[cfg(test)]` annotation](https://doc.rust-lang.org/book/ch11-03-test-organization.html#the-tests-module-and-cfgtest).
- > The `#[cfg(test)]` annotation on the tests module tells Rust to compile and run the test code only when you run `cargo test`, not when you run `cargo build`. This saves compile time when you only want to build the library and saves space in the resulting compiled artifact because the tests are not included. You’ll see that because integration tests go in a different directory, they don’t need the `#[cfg(test)]` annotation. However, because unit tests go in the same files as the code, you’ll use `#[cfg(test)]` to specify that they shouldn’t be included in the compiled result.
- As it says, it is just a way to separate tests from the library itself; the other way is to use a separate directory.
- Creating tests outside of such a module actually does work, and as [cafce25's answer](https://software.codidact.com/posts/287585/288279#answer-288279) mentions, `#[test]` already implies `#[cfg(test)]`. However, you might also have helper functions or mocks for your tests that you also don't want to include in your final non-test binary. By putting them all into one module, you not only group them semantically, but this also allows you to `#[cfg(test)]` all of them in one place rather than adding it to each of them individually.
#1: Initial revision
by
Moshi
·
2022-12-18T23:55:39Z (over 1 year ago)
The important part here is the [`#[cfg(test)]` annotation](https://doc.rust-lang.org/book/ch11-03-test-organization.html#the-tests-module-and-cfgtest). > The `#[cfg(test)]` annotation on the tests module tells Rust to compile and run the test code only when you run `cargo test`, not when you run `cargo build`. This saves compile time when you only want to build the library and saves space in the resulting compiled artifact because the tests are not included. You’ll see that because integration tests go in a different directory, they don’t need the `#[cfg(test)]` annotation. However, because unit tests go in the same files as the code, you’ll use `#[cfg(test)]` to specify that they shouldn’t be included in the compiled result. As it says, it is just a way to separate tests from the library itself; the other way is to use a separate directory. Creating tests outside of such a module actually does work, though from the wording I would assume doing so would have the test end up in the resulting binary, which may be undesirable.