Set up hardware-in-loop testing

[jessebraham]

We have already set up self-hosted runners for GitHub actions.

We will need to better define what is required in order to bring this to fruition.

EDIT: There have been a number of updates on this task, please see the comments below!

[jessebraham]

Having issues with probe-rs, same error as reported here: probe-rs/probe-rs#1829

[SergioGasquez]

The probe-rs issue is now fixed (probe-rs/probe-rs#1832) but not yet released

[jessebraham]

I have managed to flash and run tests on-device using teleprobe/probe-rs and defmt, so we're unblocked and back on track here. I've written a simple test for GPIO so far, which I've played with a bit and seems to be working as expected.

I will continue writing tests, and also start working on getting the CI workflow set up to invoke them.

[bugadani]

Test cases that would be useful, a working list:

• embedded-hal DMA driver returns error when transfering from ROM (I don't have a good reproducer for someone's issue around this)
• short waits should not block embassy (systimer driver is/was buggy, workaround in Fix us waits in embassy hanging #906)

[jessebraham]

This week had some unexpected work pop up, so I unfortunately have not made as much progress and I had hoped. However, I will still provide some updates on the current status of things:

• I have written a CI workflow which should handle building the tests and running them on-device via our self-hosted runners. This needs a bit of work still, but is mostly complete.
• There are some logistical/devops issues which need solving still, which I will discuss with a colleague who works with CI as soon as possible. These are not technically blocking issues, however, but still need to be addressed eventually.
• The plan is to initially start with with just the single GPIO test binary, to prove out the process/workflow, and then additional tests can be added.
• @t-moe has opened a PR adding RISC-V support to defmt-test and panic-probe: (risc-v support for defmt-test knurling-rs/defmt#796). Once this is merged we will use this.

[jessebraham]

Things are moving fast in the embedded testing world, and only two weeks later things are looking a bit different!

• I have switched from defmt-test to embedded-test
  • https://github.com/probe-rs/embedded-test
• I have simplified much of the configuration, and came up with solutions for passing the chip and target to the test runner
• I have begun documenting how to write and run tests
• GPIO tests are still working, planning to write simple UART and Full-Duplex SPI tests too, probably, just to help get things started
• I still need to sort out some details with the CI workflow, but I'd say it's probably 80% of the way there

I think I can actually get a draft PR opened for this soon, and I will add the CI workflow at a later date, once it is ready. At least would be nice to get some eyes on what I've come up with so I can elicit some feedback.