Stricter panic assertions

[tommy-gilligan]

Assertions on the message of the panic could be helpful for further development eg. adding labels to expectations (they would be included in messages)
Also helps tests document themselves better without comments.

[dbrgn]

Thanks, this looks like a good idea!

Could you rebase your branch against current main?

[tommy-gilligan]

I ended up redoing the work and force pushing. Felt I might as well because the work hadn't yet been done for eh1 anyways. Hope the force push isn't too confusing.

On the earlier version of this work I was matching on substrings

#[should_panic(expected = "i2c::write data does not match expectation")]

In this redo, I have gone with matching on the full string

#[should_panic(expected = "assertion failed: `(left == right)`\n  left: `[1, 2]`,\n right: `[1, 3]`: i2c::write data does not match expectation")]

This feels like maybe it's a bit extra. Please let me know your preference.

[dbrgn]

This feels like maybe it's a bit extra. Please let me know your preference.

I'm a bit unsure. I probably would have included only substrings, but the full messages also have some advantages, so I'll merge this as-is for now.