View Source Repatch

Repatch is a library for efficient, ergonomic and concise mocking/patching in tests (or not tests)

Features

  1. Patch any function or macro (except NIF and BIF). You can even patch and call private functions in test, or Erlang modules

  2. Designed to work with async: true. Has 3 isolation levels for testing multi-processes scenarios.

  3. Does not require any explicit boilerplate or DI. Though, you are completely free to use it with Repatch!

  4. Powerful call history tracking.

  5. super and real to help you call real implementations of the module.

  6. Works with other test frameworks and even in non-testing environments like iex or remote shell.

Installation 

def deps do
  [
    {:repatch, "~> 1.0"}
  ]
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 or Repatch.fake to change implementation of any function and 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 ->
      %{thats_not: :a_map_set}
    end)

    assert MapSet.new() == %{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.