Cannot run cargo test using fresh template

[teotwaki]

Hi,

This may be self-evident, and if it is I apologise. It appears that one cannot use cargo test using a fresh cargo generated project based on this template:

$ cargo generate --git https://github.com/esp-rs/esp-template
[...]
🔧   Generating template ...
✔ 🤷   Enable allocations via the esp-alloc crate? · true
✔ 🤷   Which MCU to target? · esp32
✔ 🤷   Configure project to use Dev Containers (VS Code, GitHub Codespaces and Gitpod)? · false
[...]
$ cd foo
$ cargo test
[...]
   Compiling foo v0.1.0 (/Users/slau/src/unticks/foo)
error[E0463]: can't find crate for `test`

For more information about this error, try `rustc --explain E0463`.
error: could not compile `foo` due to previous error

Not sure if this is expected, intended, or unfixable.

[MabezDev]

Hi, thanks for the issue! Testing on no_std is pretty target specific, so there isn't a general solution. The most common pattern I see is running tests on the host machine instead. This of course requires writing tests in a certain way (i.e, can't rely on hardware features of the chip). I know this doesn't help immediately but hopefully gives you some pointers to get a test setup working for you :). If you do find a good pattern, that would work in the template, would you mind submitting a PR?

[teotwaki]

Hi!

I understand that testing on device is very specific, however I guess my question was more: why is the #[test] macro broken in projects generated using the template? I have a no_std library where tests work fine.

Is there a specific thing that is done in the template which prevents the use of #[test]? Is this by design or a known side-effect?

[jessebraham]

I would guess it's because there's no .cargo/config.toml file in that library, but that's just a guess.

[MabezDev]

Library crates can be compiled for any arch (provided they don't contain any target-specific asm), this isn't generally the case for binary crates, which this template produces. In general, I see folks splitting their code into lib and bin, and adding testing in the lib crate, like you did for yours above.

[elpiel]

I would like to join in this discussion as well.
Lately I've been running tests under linux and there is a way to support cargo test.

On the flip side, I'm getting an issue with esp-hal-common and needs upstream fixing to make it work.
Would be nice to set up defmt_test too for the template to run tests on the device