Validation - Custom Message

Setup

defmodule Foo do
  use(Mazurka.Resource)

  param(foo)

  validation(foo != "bar", "Uh oh...")

  mediatype(Hyper) do
    action() do
      %{"foo" => foo}
    end
  end
end

action

try() do
  Foo.action([], %{"foo" => "bar"}, %{}, %{})
rescue
  e in [Mazurka.ValidationException] ->
    assert(e.message() == "Uh oh...")
end