Mock Authority for testing Authoritex consumers

Examples:

  # In test.exs:
  # config :authoritex, authorities: [Authoritex.Mock]

  # In test_helper.exs:
  # Authoritex.Mock.init()

  # In test case:
  iex> Authoritex.Mock.set_data([
    %{id: "mock:result1", label: "First Result", qualified_label: "First Result (1)", hint: "(1)"},
    %{id: "mock:result2", label: "Second Result", qualified_label: "Second Result (2)", hint: "(2)"},
    %{id: "mock:result3", label: "Third Result", qualified_label: "Third Result (3)", hint: "(3)"}])
  :ok

  iex> Authoritex.fetch("mock:result2")
  {:ok, %{id: "mock:result2", label: "Second Result", qualified_label: "Second Result (2)", hint: "(2)"}}

  iex> Authoritex.fetch("missing_id_authority:anything")
  {:error, 404}

  iex> Authoritex.fetch("wrong")
  {:error, :unknown_authority}

  iex> Authoritex.search("mock", "test")
  {:ok, [
          %{id: "mock:result1", label: "First Result", hint: "(1)"},
          %{id: "mock:result2", label: "Second Result", hint: "(2)"},
          %{id: "mock:result3", label: "Third Result", hint: "(3)"}
        ]}

  iex> Authoritex.search("mock", :no_results)
  {:ok, []}

  iex> Authoritex.search("mock", :error)
  {:error, 500}