TestingAdapter `deliver` function doesn't return the same type as ExternalSmtpAdapter

[martinos]

The TestingAdapter.deliver function returns a Task, however the ExternalSmtpAdapter.deliver returns a tuple: {:ok, message}.

I think that both function should return the same type, it would make tests behave more like production code.

[IamfromSpace]

+1 for this. Will be pointing to your branch until the PR goes through.

[hamann]

@kamilc Is there a reason to have different results? Writing code with tests and matching against result isn't possible because of this

[zberkom]

👍 Experiencing the same issue here. Both adapters should return a Task.