Stuff You Didn't Know You Can Do with RSpec

My presentation at Rails Israel on November 12, 2012

More information about custom matchers can be found on my blog post here: http://www.codelord.net/2012/02/04/extend-your-toolbox-custom-matchers/

Transcript

1. BE AWESOME With RSpec
2. AVIV BEN-YOSEF @avivby codelord.net podcast rauchy.net/truby
3. TESTS! YAY
4. TEST ALL THE THINGS!
5. SOON AFTER
6. KENT BECK
7. 4 RULES of SIMPLE DESIGN
8. RULE #1 PASSES ITS TESTS
9. PASSES ITS TESTS WHEN TESTS DONT PASS
10. PASSES ITS TESTS xit “does something” do ... end
11. PASSES ITS TESTS RUNNING A SINGLE EXAMPLE
12. PASSES ITS TESTS it “is important” do ... end it “is not important” do ... end
13. PASSES ITS TESTS it “is important” do ... end xit “is not important” do ... end
14. PASSES ITS TESTS it “is important”, :focus => true do ... end it “is not important” do ... end $ rspec -t focus
15. PASSES ITS TESTS focused “is important” do ... end it “is not important” do ... end $ rspec -t focus
16. PASSES ITS TESTS it “is pending” do pending “not implemented yet” do something.should be_false end end SPECS THAT SHOULDNT PASS
17. RULE #2 REVEALS INTENT
18. REVEALS INTENT NAME IT LIKE YOU MEAN IT
19. describe == context
20. it == specify == example
21. double == stub == mock
22. REVEALS INTENT + PASSES ITS TESTS MATCHERS FTW The right matchers reveal more intent both at read time and runtime
23. Failure: Counter.count.should == 1 expected: 1 got: 0 (using ==) REVEALS INTENT + PASSES ITS TESTS Counter.increment Counter.count.should == 1
24. result should have been changed to 1, but is now 0 REVEALS INTENT + PASSES ITS TESTS expect {Counter.increment}.to change {Counter.count}.from(0).to(1)
25. Failure: user.cart.size.should == 2 expected: 2 got: 0 (using ==) REVEALS INTENT + PASSES ITS TESTS user.cart.size.should == 2
26. expected 2 items, got 0 REVEALS INTENT + PASSES ITS TESTS user.cart.should have(2).items
27. expected false to be true REVEALS INTENT + PASSES ITS TESTS user.active?.should be_true
28. expected active? to return true, got false REVEALS INTENT + PASSES ITS TESTS user.should be_active
29. expected false to be true REVEALS INTENT + PASSES ITS TESTS user.has_orders?.should be_true
30. expected #has_orders? to return true, got false REVEALS INTENT + PASSES ITS TESTS user.should have_orders
31. RULE #3: DONT REPEAT YOURSELF - DRY
32. DRY DIY MATCHERS
33. Mock received :add with unexpected arguments expected: (Comment :{:anonymous=>true, :user=>"dude"}) got: (Comment :{:anonymous=>false, :user=>"dude"}) DRY + REVEALS INTENT comment = Comment.new(anonymous: true, user: "dude") commentor.should_receive(:add).with(comment)
34. expected false to be true DRY + REVEALS INTENT commentor.should_receive(:add) do |comment| comment.anonymous.should be_true end
35. Mock received :add with unexpected arguments expected: (anonymous comment) got: (Comment:{:anonymous=>false, :user=>"dude"}) DRY + REVEALS INTENT commentor.should_receive(:add) .with(anonymous_comment)
36. DRY DRY WITH CONTEXTS
37. DRY describe MyController do it “does X when user logged in” it “does Y when user logged in” it “doesn’t do X when not logged in” it “redirects when not logged in” end
38. DRY describe MyController do context “logged in” do it “does X” it “does Y” end context “not logged in” do it “doesn’t do X” it “redirects to login” end end
39. DRY DRY OBJECT CREATION
40. DRY describe MyController do it “...” do x = Foo.new(...) ... end it “...” do x = Foo.new(...) ... end end
41. DRY describe MyController do it “...” do x = Foo.new(..., noise: ‘baz’) ... end it “...” do x = Foo.new(..., noise: ‘baz’) ... end end
42. DRY describe MyController do let(:x){Foo.new(..., noise: ‘baz’)} it “...” do ... end it “...” do ... end end
43. SUMMARY MAKE YOUR TESTS PASS EXPRESS YOUR INTENT BE DRY BE AWESOME WITH RSPEC
44. THANK YOU! @avivby