I have a Behaviour that forces whoever implements it to implement a couple functions. For the sake of this discussion, let’s take the examples from the behaviours documentation.
defmodule Parser do
@callback parse(String.t) :: {:ok, term} | {:error, String.t}
@callback extensions() :: [String.t]
end
Now, let’s imagine that I see some repetition in the modules that implement this behaviour or that I want to add an universal parse!
method. The preferred approach for this would be to use dynamic dispatching:
defmodule Parser do
@callback parse(String.t) :: {:ok, term} | {:error, String.t}
@callback extensions() :: [String.t]
def parse!(implementation, contents) do
case implementation.parse(contents) do
{:ok, data} -> data
{:error, error} -> raise ArgumentError, "parsing error: #{error}"
end
end
end
But now I am left with a question. How would I test parse!
?
Since this is pretty much working like an abstarct class at this point, how would you test it?
The only way I see it would be to use a Mock for the implementation
parameter, but I am not sure about this approach.
Any ideas?