Test NifStruct derived traits

[alexkaf]

Hello all, I have the following struct created in order to bridge an Elixir struct with my NIF:

#[derive(NifStruct)]
#[module = "ElixirStruct"]
struct RustStruct {
   s1: String,
   s2: String
}

All good so far, and my NIF successfully uses this Elixir struct. However, the problem comes in my code test coverage (I use llvm-cov tool) where I cannot reach 100% since I can't to test Decode and Encode trait functions derived from NifStruct. I find some trouble creating a custom Env in my tests in order to test these functions (not sure if it is possible).

Is there a way to either ignore these trait definitions (probably an llvm-cov issue but still didn't find a way to do so) or even better create tests to cover these lines as well?