How to test Commander code in my app

Realised that I left that code untested and #52 crashed everything in production.

Assuming I have simple commander like this:
```elixir
defmodule FooCommander do
use Drab.Commander

def pres_buton(socket, _sender) do
Drab.Live.poke(socket, some_variable: "new value")
end
end
```

How can I test this code? Mainly to ensure nothing is crashing there.

Thanks!