View Source Repatch

Repatch is a library for efficient, ergonomic and concise mocking/patching in tests (or not tests). It provides an efficient and async-friendly replacement for Mox, ProtoMock, Patch, Mock and all other similar libraries.

Features

  • Patches any function or macro. Elixir or Erlang, private or public (except BIF/NIF).

  • Async friendly. With local, global, and allowances modes.

  • Boilerplate-free. But you still can leverage classic explicit DI with Repatch.

  • Call history.

  • Built-in async-friendly application env. See Repatch.Application.

  • Mock behaviour and protocol implementation generation. See Repatch.Mock

  • Supports expect-style mocking. See Repatch.Expectations

  • Testing framework agnostic. It even works in iex and remote shells.

Installation 

def deps do
  [
    {:repatch, "~> 1.5"}
  ]
end

One-minute intro

for ExUnit users

  1. Add Repatch.setup() into your test_helper.exs file after the ExUnit.start()

  2. use Repatch.ExUnit in your test module

  3. Call Repatch.patch/3 to change implementation of any function in any module.

For example 

defmodule ThatsATest do
  use ExUnit.Case, async: true
  use Repatch.ExUnit

  test "that's not a MapSet.new" do
    Repatch.patch(MapSet, :new, fn _list ->
      %{thats_not: :a_map_set}
    end)

    assert MapSet.new([1, 2, 3]) == %{thats_not: :a_map_set}

    assert Repatch.called?(MapSet, :new, 1)
  end
end

Further reading

Please check out the docs for all available features.

Special thanks

To ihumanable for Patch library which was an inspiration and a good example for Repatch.