I have problems with unit tests in my workspace. I have a workspace with two crates - a firmware crate and a library crate. The library crate is `#![cfg_attr(not(test), no_std)]`. The firmware crate is `#![no_std]`. The library crate defines tests. It uses the `test-case` crate as a dev-dependency. When it was a standalone no_std crate, it was completely fine (even with just no_std, without the cfg_attr). `cargo t` is no fun:

```
error[E0463]: can't find crate for `std`
  |
  = note: the `thumbv6m-none-eabi` target may not support the standard library
  = note: `std` is required by `test_case` because it does not declare `#![no_std]`
```