How I Learned to Stop Worrying and Like RSpec

Miami Ruby Brigade, Sept. 15

Transcript

1. How I Learned to Stop Worrying and Like RSpec Bryce Kerley Miami Ruby Brigade Sept. 15, 2014
2. Preemptive Answers Yes, the slides will be online Yes, the code samples are online
4. Please Test Your Important Code
5. I Like RSpec • Testing, TDD, and Agile • Minitest features • How I got to RSpec • RSpec philosophy • RSpec practice
6. Agile If you’re not sure what to do yet, do the simplest thing that could possibly work. http://www.artima.com/intv/simplest3.html
7. Testing Defines “work”
8. Testing Tells you when you break stuff
9. Forget Manual Testing Error-prone Doesn’t test all interactions Especially ones that are a pain
10. Test-Driven Development 1. Write failing test for feature 2. Write code to pass the failing test 3. Write code to pass tests you broke 4. Clean up your mess
11. Test-driven development is about not being afraid to try something. If you break it, you’ll know, and you’re a `git checkout` away from fixing it.
12. I Like RSpec • Testing, TDD, and Agile • Minitest features • How I got to RSpec • RSpec philosophy • RSpec practice
13. Conway's Game of Life • Grid of cells • Live cells with two or three neighbors stay alive • Dead cells with three neighbors come to life
14. Five Minutes of Minitest require 'minitest/autorun' ! class CellTest < Minitest::Test def test_counts_neighbors c = Cell.new(0, 0) assert_equal 0, c.neighbors ! c2 = Cell.new(1, 0) assert_equal 1, c.neighbors end ! def test_comes_to_life end def test_stays_alive end end
15. Minitest in Rails require 'test_helper' ! class PostTest < ActiveSupport::TestCase test 'a post has many comments' do p = Post.create assert_empty p.comments c = Comment.create post: p refute_empty p.comments end end
16. Minitest with Nesting Minitest::Test can’t Minitest::Spec can
17. Minitest with Mocking def test_comes_to_life @board = Minitest::Mock.new @board.expect :neighbors, 3 ! c = Cell.new(@board, 0, 0) ! assert c.become_alive? end
18. I Like RSpec • Testing, TDD, and Agile • Minitest features • How I got to RSpec • RSpec philosophy • RSpec practice
19. basho My Day Job Three years at Basho! We’re hiring!
20. Riak Ruby Client • Started January 2010 • RSpec from the beginning • I took over May 2013 • 5833 lines of RSpec tests As of Thursday we have 5750 lines of tests, but we ripped out a bunch of complex systems.
22. My Transition Copying and modifying existing specs My first commit on riak-ruby-client had a zillion assignments in a `before` block.
23. My Transition Finding good documentation It’s the rspec organization on “relishapp”, link later.
24. My Transition Practice and review All my RSpec work was code-reviewed and commented on, which helped.
25. My Transition Second nature Today, I’d rather write RSpec for new work even knowing my previous complaints about it.
26. I Like RSpec • Testing, TDD, and Agile • Minitest features • How I got to RSpec • RSpec philosophy • RSpec practice
27. https://twitter.com/srbaker/status/345035925232955393
28. RSpec Philosophy • Write yellow skeleton specs • Implement an expectation so it’s red • Fulfill an expectation to make it green
29. Conway's Game with RSpec describe Cell do subject { described_class.new(0, 0) } ! it 'comes to life appropriately' it 'stays alive appropriately’ ! it 'counts neighbors' do expect(subject.neighbors).to eq 0 ! c2 = described_class.new(1, 0) expect(subject.neighbors).to eq 1 end end Spec group Skeletons Spec Expectation
30. RSpec in Rails require 'rails_helper' ! RSpec.describe Post, :type => :model do subject{ described_class.create } ! it 'has many comments' do expect(subject.comments).to be_empty c = Comment.create post: subject expect(subject.comments).to_not be_empty end end
31. Batteries Included • rspec-core: contexts, syntax • rspec-expectations: basically assertions • rspec-mocks: mocks, doubles, stubs
32. RSpec Philosophy RSpec is a product
33. I Like RSpec • Testing, TDD, and Agile • Minitest features • How I got to RSpec • RSpec philosophy • RSpec practice
34. Easy to Install • Not Rails: rspec --init • Rails: gem 'rspec-rails' in your Gemfile
35. The Syntax it{ is_expected.to be } subject(:post){ Post.new } expect(something.else).to eq 5 expect(somebody).to be_lovable allow(some_mock).to receive :method expect{ something.method }.to raise_error
36. The Syntax • A confusing mish-mash of spaces, underscores, dots, parens, braces, symbols, strings • Oh, and words
37. Let & Subject describe “CRDTs" do let(:bucket) { random_bucket } ! describe 'counters' do subject { Riak::Crdt::Counter.new bucket, random_key } ! it 'asks for and accepts a returned body' do other = Riak::Crdt::Counter.new(subject.bucket, subject.key) end end end
38. Let & Subject • let defines a variable only when you need it
39. Let & Subject class Turn def initialize puts "ACTUALLY BEING INITIALIZED" end end ! describe Turn do let(:turn){ Turn.new } ! it "might not get initialized" do expect(5).to eq 5 end ! it "is only initialized on use" do expect(turn).to be_a Turn end end
40. Let & Subject • subject defines a variable named “subject” only when you need it • Is implicitly defined to described_class.new • Allows implicit usage with it { is_expected… }
41. Let & Subject class Board def cromulent? true end end ! describe Board do it { is_expected.to be } it { is_expected.to be_a Board } it { is_expected.to be_cromulent } end
42. Quick Boolean Matchers • Quickly verify any question? methods that take no arguments: • expect(my_object).to be_cromulent • Passes if cromulent? returns true-y
43. Tagging & Focus Tagging allows subsets of tests to be run
44. Tagging & Focus describe 'Secure Protobuffs’ do ! describe 'without security enabled on Riak', no_security: true do it 'connects normally without authentication configured' do … ! describe 'with security enabled on Riak', yes_security: true do it 'connects normally with authentication configured' do These tests are mutually exclusive; they require server settings to be toggled and local configuration settings to match. I use tags to control which set runs.
45. Tagging & Focus • focus is a tag with quick syntax • skip is metadata with quick syntax • “describe” to “fdescribe” or “xdescribe” • “it” to “fit” or “xit” • rspec ./spec/some_specs/… -t focus
46. Customizing & Promode • Put a .rspec file in your project root --format documentation --color
47. Promode
48. I Like RSpec • Testing, TDD, and Agile • Minitest features • How I got to RSpec • RSpec philosophy • RSpec practice
49. Please Test Test-driven development makes your project better
50. Minitest is Good Minitest comes with Ruby and it's good at getting the job done
51. Bryce and RSpec I started with RSpec because I had to I got good with RSpec because I enjoyed it
52. RSpec Philosophy Everything you need to test behavior of objects If it’s hard to do with RSpec, consider if it’s the right thing to do.
53. RSpec Practice Start with skeletons Describe behavior Make it pass
54. Thanks Bryce Kerley bkerley@brycekerley.net https://twitter.com/bonzoesc https://github.com/bkerley
55. Docs and References https://pinboard.in/u:bryce/t:rspec-miamirb/ https://relishapp.com/rspec/ http://rspec.info http://rdoc.info/gems/minitest/frames https://github.com/bkerley/rspec-miamirb/branches