Bow Before MiniTest - Speaker Deck

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Bow Before MiniTest @adman65 - gh://twinturbo

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MiniTest vs RSpec vs Test::Unit vs Cucumber

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Forget Cucumber! • Long term cucumber use is detrimental to your brain • Makes you learn another syntax to write tests • Managing large test suites is painful • Small number of good use cases

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MiniTest vs RSpec vs Test::Unit vs Cucumber

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MiniTest & Test::Unit • Test::Unit is MiniTest in Ruby 1.9 • Test::Unit is a compatibility layer around MiniTest • This is for backward compatibility • We can forget about Test::Unit too...

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MiniTest vs RSpec vs Test::Unit vs Cucumber

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MiniTest vs RSpec

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Kampf!

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Things a Test Framework Should Do • Make it easy to write and maintain tests • Run tests in random order • Believe me, this will ﬁnd bugs in your code • Make you focus on testing your code and not learning the framework yourself

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Basics: Writing Tests

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require 'minitest/autorun' class TruthTest < MiniTest::Unit::TestCase def test_truth assert true end end

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require 'rspec' describe "Truth" do it "should be true" do true.should == true end end

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Speed: Timing 10K Tests

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require 'test_helper' class TruthTest < MiniTest::Unit::TestCase 10_000.times do |i| define_method "test_truth_#{i}" do assert true end end end

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require 'spec_helper' describe "Truth" do 10_000.times do it { should_not be_nil } end end

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Results # Tests MiniTest Rspec 1.000 0.069 0.428 10.000 0.730 3.92 100.000 8.345 39.53 Times in Seconds

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Yes, this is Real :(

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Analysis • MiniTest is clearly faster on tremendously large test suites • MiniTest is notably faster on smaller tests suites • RSpec will continue to slow down rapidly because matchers create objects which trigger garbage collection • Developers may notice a difference in typical test suites

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Expressiveness: should vs assert

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Rspec is testing DSL

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describe Person do its(:phone_number) { should =~ /^\d+$/ } end

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MiniTest is Ruby

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class PersonTest < MiniTest::Unit::TestCase def test_phone_number_format person = Person.new assert_match person.phone_number, /^\d+$/ end end

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Magic • RSpec: less code & more magic • MiniTest: more code & less magic

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# 1. describe Person detects that the described # object is a class so `Person.new` is called # implicitly before each test and assigned to # `subject` describe Person do its(:phone_number) { should =~ /^\d+$/ } end

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describe Person do # Call the `phone_number` method on subject # an assign it's return value to `subject` # inside the test block its(:phone_number) { should =~ /^\d+$/ } end

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describe Person do # Call should on the implicit subject # so it can be tested against the regex its(:phone_number) { should =~ /^\d+$/ } end

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I don’t like this complexity

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Do I need to explain MiniTest?

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Custom Matchers vs Custom Assertions

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def assert_valid(model) assert model.valid?, "Expected #{model} to be valid" end

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# There is a large API for this! # This is the most simple case RSpec::Matchers.define :be_valid do match do |model| model.valid? end end

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Go read this ﬁle: https://github.com/rspec/ rspec-expectations/blob/master/lib/rspec/ matchers/built_in/base_matcher.rb

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Writing custom assertions is easier and more understandable in MiniTest

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def test_vendor_comes_before_app # do stuff to build a file content = read "site/application.js" assert_includes content, "APP" assert_includes content, "VENDOR" assert content.index("VENDOR") < content.index("APP"), "Vendor should come before App!" end

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extract-method

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def test_vendor_comes_before_app content = read "site/application.js" assert_before content, "VENDOR", "APP" end def assert_before(source, first, second) assert_includes content, first assert_includes content, second assert content.index(first) < content.index(source), "#{first} should be before #{second}" end

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One Less Thing to Learn

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You Don’t need to lookup a Matcher API, just write ruby methods

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MiniTest will make your code better

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Why? • Minimal feature set: focus on writing code • Removing a complex mocking/stubbing library makes you consider design • Run tests in random order--this will usually ﬁnd bugs in your test suite or code • Can run your tests in parallel

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class OrderDependentTest < MinitTest::Unit::TestCase i_suck_and_my_tests_are_order_dependent! def test_step1 # .... end def test_step2 # .... end end If you do in fact, suck at writing tests....

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require 'minitest/unit' require 'minitest/hell' # put your tests through the ringer require 'minitest/autorun' class ParallelTests < MiniTest::Unit::TestCase def test_multi_threading # ... end end

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tl;dr

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Why MiniTest? • Its faster and lighter than Rspec • Its much easier to understand and extend • Random & parallel tests out of the box • Its part of the standard library so it’s available everywhere • More stable and better supported than Rspec • It will make your test suite better!

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Why Rspec? • $ rspec foo_spec.rb • Running individual tests is trivially easy • You like DSL’s and complexity

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