The [page on testing][1] suggests this:

> Where possible, and where it makes sense, you should try to test as much as possible on your host machine, not on the target device.

When I have tried this I have encountered multiple problems, first that the Rust test framework requires std, making it convoluted writing test code – but when working around that using conditional compilation, I run into other things like the `esp-hal` depending on crates that won't compile on the host.

What is the recommended way to test on the host?

  [1]: https://docs.espressif.com/projects/rust/book/application-development/testing.html

▲ bigfishrunning 3 hours ago | parent | next [-]

Especially for embedded work (but for regular software too!) I've bought into the "sans-io pattern" for a lot of the software i write anymore

https://sans-io.readthedocs.io/how-to-sans-io.html

Keeping all of the actual hardware/network/io interface code separate really makes writing unit tests and porting to different computers much simpler

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tylerc230 3 hours ago | parent | next [-]

I do something similar. I have all my esp/idf code in one crate and all my business logic in a separate crate. The business crate has no dependencies that won’t compile/run on the host. This is where all my tests live.

	▲	sensora an hour ago \| parent [-]
		[flagged]

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tredre3 3 hours ago | parent | prev [-]

This is good advice however it should be noted that many of espressif's other purely software components depend on esp-hal, so you still want it to compile if you use any of espressif's provided components.

▲ officialchicken 2 hours ago | parent | prev | next [-]

I don't use the the builtin testing framework, or std, and I often explicitly use a no-heap crate. Check out Embassy and you'll be free to ignore pretty almost everything suggested here, especially when developing and testing. I create a separate [bin] for each test (I usually run out of flash to fit all the tests into a single binary), and a few lines of bash/python to make a test runner/reporter for all the flashing and running of tests. Sometimes I flash up to 50 times a day and haven't lost an MCU (AVR-Rust, ESP-Rust, STM-Rust) yet due to too many writes.

[0] https://github.com/embassy-rs/embassy

▲ devmor 3 hours ago | parent | prev [-]

This is a constant issue for me in every facet of embedded development - with the sole exception of devices that can easily be tested in a qemu environment.

I would also love to hear that the authors of this book suggest.