@spec mockable(
  mod :: module(),
  opts :: [{:by, module()}]
) :: module()

Function used to prepare module for mocking/asserting.

For Mix.env other than :test it returns the first argument unchanged. If Mix.env equal :test it creates a proxy to the original module. When Mix is missing it assumes that env is :prod.

Examples

Prepare for mocking

defmodule Foo do
  use Mockery.Macro

  def foo do
    mockable(Bar).bar()
  end
end

Prepare for mocking with global mock

# test/support/global_mocks/bar.ex
defmodule BarGlobalMock do
  def bar, do: :mocked
end

# lib/foo.ex
defmodule Foo do
  use Mockery.Macro

  def foo do
    mockable(Bar, by: BarGlobalMock).bar()
  end
end

Mockery.of/2 comparison

• It's based on macro and process dictionary instead of on tuple calls. (Tuple calls are disabled by default in OTP21+ and require additional compile flag to be reenabled)
• It doesn't support passing module names as a string as it don't create unwanted compile-time dependencies between modules

Potential issues

Output of mockable/2 macro should not be bind to variable or module attribute. If it happens, you'll see a compilation warning at best, and in the worst case Mockery won't work correctly.