Rails 5 Test Prescriptions

Mocha

The Mocha library is the one Rails uses for its own testing, so it seems the natural choice for a test-double library to use with Minitest. Full Mocha docs are available online.^[55]

Installing Mocha

Mocha needs to be installed after Minitest, which requires a slight indirection to ensure your Rails app does the right thing.

First, in the Gemfile’s :test group, add the Mocha gem:

gem "mocha"

Then, inside the test/test_helper.rb file, you manually require Mocha at any point in the file after the rails/test_help library is loaded:

require "mocha/mini_test"

At that point you should be good to go. Please see Chapter 7, ​Using Test Doubles as Mocks and Stubs​, for a full discussion of test doubles. Here I’ll cover only Mocha syntax.