Minitest cheatsheet

Usage

require 'minitest/autorun'

describe "X" do
  before do .. end
  after do .. end
  subject { .. }
  let(:list) { Array.new }

  it "should work" do
    assert true
  end
end

Specs (.must/.wont)

expect(x)
.must_be :==, 0
.must_equal b
.must_be_close_to 2.99999
.must_be_same_as b

.must_include needle
.must_be_empty

.must_be_kind_of
.must_be_instance_of
.must_be_nil
.must_match /regex/
.must_be :<=, 42
.must_respond_to msg

.must_be_silent  ( proc { "no stdout or stderr" }.must_be_silent)
.must_output "hi"

proc { ... }.must_output out_or_nil [, err]
proc { ... }.must_raise exception
proc { ... }.must_throw sym

Test

class TestHipster < Minitest::Test
  def setup
    @subject = ["silly hats", "skinny jeans"]
  end

  def teardown
    @hipster.destroy!
  end

  def test_for_helvetica_font
    assert_equal "helvetica!", @hipster.preferred_font
  end

  def test_not_mainstream
    refute @hipster.mainstream?
  end
end

Assertions

assert
assert_block { ... }
assert_empty
assert_equal 2, @size
assert_in_delta @size, 1, 1
assert_in_epsilon
assert_includes @list, "item"
assert_instance_of Array, @list
assert_kind_of Enumerable, @list
assert_match @str, /regex/
assert_nil
assert_operator @n, :==, 0
assert_output
assert_raises
assert_respond_to
assert_same
assert_send
assert_silent
assert_throws

Minitest::Mock

A simple and clean mock system. There two essential methods at our disposal: expect and verify.

require 'minitest/autorun'

describe Twipster, "Make every tweet a hipster tweet." do
  before do
    @twitter  = Minitest::Mock.new
    @twipster = Twipster.new(@twitter)
  end

  it "should append a #lolhipster hashtag and update Twitter with our status" do
    tweet = "Skyrim? Too mainstream."
    @twitter.expect :update, true, ["#{tweet} #lolhipster"]
    @twipster.submit(tweet)
    assert @twitter.verify # verifies tweet and hashtag was passed to `@twitter.update`
  end
end

Reporters

gem 'minitest-reporters'

require 'minitest/reporters'
Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new

[Default, Spec, Progress, RubyMate, RubyMine, JUnit]