Intro to TDD with Ruby's minitest

• http://tutorials.jumpstartlab.com/topics/testing/intro-to-tdd.html

See also: https://semaphoreci.com/community/tutorials/getting-started-with-minitest

Requisites

We're going to implement a small unicorn class with these requirements:

• unicorns have names
• they are usually white, but can be any color
• they say "sparkly" things (don't worry, we'll explain what this means).

Setup

This will install minitest globally:

gem install minitest

Creating projects dir/files:

mkdir unicorn
cd unicorn
touch unicorn_test.rb
touch unicorn.rb

# configuring minitest:
gem 'minitest', '~> 5.0'
require 'minitest/autorun'
require 'minitest/pride' # colors! :)

# loading the class we want to test
require_relative 'unicorn'

# starting the test suite
class UnicornTest < Minitest::Test
end

To run the test:

ruby unicorn_test.rb

Assertions

docs

• assert_equal(expected, actual, msg = nil)
• assert(test, msg = nil)
  • use it instead of assert_equal true, test
• refute(test, msg = nil)
  • use it instead of assert_equal false, test

Skipping a Test

A test can be skipped with skip.

Example:

def test_something_else
  skip
  assert_equal 1, nil - 1
end