https://github.com/ckrenslehner/embedded-test-issue/tree/feat/workspace

Can anyone help me wrapping my head around cargo workspaces with different targets?
Basically I want the following:

- A workspace
- A arm-none-eabi crate for the firmware (app in the repo)
- Other crates which can be tested on the host and can be used in the firmware (shared in the repo)
- I want to share crates versions betweent -> thats why the workspace
- I want to run `cargo b` and `cargo test` in the workspace and run host tests but also embedded tests
- I want to dictate the exact arm-none-eabi target via Config.toml within the app dir

Is this just not possible? 
I always have to exclude the app dir, because otherwise I get linker errors