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MiniTest quick reference

MiniTest::Spec

use must for positive expectations and wont for negative expectations.

  • must_be | list.size.must_be :zero?
  • must_be_close_to | subject.size.must_be_close_to 1,1
  • must_be_empty | list.must_be_empty
  • must_be_instance_of | list.must_be_instance_of Array
  • must_be_kind_of | list.must_be_kind_of Enumerable
  • must_be_nil | list.first.must_be_nil
  • must_be_same_as | subject.must_be_same_as subject
  • must_be_silent | proc { "no stdout or stderr" }.must_be_silent
  • must_be_within_epsilon | subject.size.must_be_within_epsilon 1,1
  • must_equal | subject.size.must_equal 2
  • must_include | subject.must_include "skinny jeans"
  • must_match | subject.first.must_match /silly/
  • must_output proc |{ print "#{subject.size}!" }.must_output "2!"
  • must_respond_to | subject.must_respond_to :count
  • must_raise | proc { subject.foo }.must_raise NoMethodError
  • must_send | subject.must_send [subject, :values_at, 0]
  • must_throw | proc { throw :done if subject.any? }.must_throw :done
require 'minitest/autorun'

describe Hipster, "Demonstration of MiniTest" do
  before do
    @hipster = Hipster.new
  end

  after do
    @hipster.destroy!
  end

  subject do
    Array.new.tap do |attributes|
      attributes << "silly hats"
      attributes << "skinny jeans"
    end
  end

  let(:list) { Array.new }

  describe "when asked about the font" do
    it "should be helvetica" do
      @hipster.preferred_font.must_equal "helvetica"
    end
  end

  describe "when asked about mainstream" do
    it "won't be mainstream" do
      @hipster.mainstream?.wont_equal true
    end
  end
end

MiniTest::Test

use assert for positive assertions and refute for negative assertions

  • assert | assert @subject.any?, "empty subjects"
  • assert_block | assert_block { @subject.any? }
  • assert_empty | assert_empty @list
  • assert_equal | assert_equal 2, @subject.size
  • assert_in_delta | assert_in_delta @subject.size, 1,1
  • assert_in_epsilon | assert_in_epsilon @subject.size, 1, 1
  • assert_includes | assert_includes @subject, "skinny jeans"
  • assert_instance_of | assert_instance_of Array, @list
  • assert_kind_of | assert_kind_of Enumerable, @list
  • assert_match | assert_match @subject.first, /silly/
  • assert_nil | assert_nil @list.first
  • assert_operator | assert_operator @list.size, :== , 0
  • assert_output | assert_output("Size: 2") { print "Size: #{@subject.size}"}
  • assert_raises | assert_raises(NoMethodError) { @subject.foo }
  • assert_respond_to | assert_respond_to @subject, :count
  • assert_same | assert_same @subject, @subject, "It's the same object silly"
  • assert_send | assert_send [@subject, :values_at, 0]
  • assert_silent | assert_silent { "no stdout or stderr" }
  • assert_throws | assert_throws(:error,'is empty') {throw :error if @subject.any?}
require 'minitest/autorun'

class TestHipster < MiniTest::Test
  def setup
    @hipster = Hipster.new
    @list    = Array.new
    @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

MiniTest::Mock

there two essential methods at our disposal: expect and verify

require 'minitest/autorun'

class Twipster
  def initialize(twitter)
    # A Ruby wrapper for the Twitter API
    @twitter = twitter
  end

  def submit(tweet)
    @twitter.update("#{tweet} #lolhipster")
  end
end

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

Credits

This is slightly modified version of @mattsears's article http://mattsears.com/articles/2011/12/10/minitest-quick-reference/ just in case,if some servers stop working :)

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