Testing Should Be Fun

Kent Beck’s first articles about Test-Driven Development. I don’t think I’m alone in being drawn to TDD at first because it was fun. The quick and consistent feedback and the ability to turn complicated problems into a series of smaller problems to be solved made TDD development seem more like a game than work.

Eventually TDD became less fun. Slow tests made running test suites a cruel joke. Test code gets bulky, and is hard to refactor because, of course, tests don’t have their own tests.

Let’s fix that. We’ll show some notorious testing joy-killers, like slow tests, hard to read tests, tests that paper over bad designs rather than driving new ones. And we’ll squash them, and regain testing delight.

Transcript

1. Testing Should Be Fun Noel Rappin @noelrap Saturday, November 3, 12
2. Who is this guy? Saturday, November 3, 12
3. Kent Beck Saturday, November 3, 12
4. Saturday, November 3, 12
5. Saturday, November 3, 12
6. In 2001, this was my RSpec Saturday, November 3, 12
7. Saturday, November 3, 12
8. Avdi Grimm, "Confident Ruby" Saturday, November 3, 12
9. "This talk is fundamentally about joy." Saturday, November 3, 12
10. Do we still love writing tests? Saturday, November 3, 12
11. Or do we just love having written tests? Saturday, November 3, 12
12. Or do we just love saying that we've written tests? Saturday, November 3, 12
13. What makes testing fun? Saturday, November 3, 12
14. Feedback Saturday, November 3, 12
15. Communication Saturday, November 3, 12
16. What makes testing painful? Saturday, November 3, 12
17. Long run times Flakey Behavior Impentrable Saturday, November 3, 12
18. Big Test Suites Saturday, November 3, 12
19. Red. Green. Refactor. Saturday, November 3, 12
20. The Real TDD Cycle: Saturday, November 3, 12
21. Red. Green. Refactor.... Saturday, November 3, 12
22. Green. Green. Green. Green. Green. Green. Green. Green. Green. Green. Green. Green. Green. Green. Green. Saturday, November 3, 12
23. Tests are run way, way more than they are written Saturday, November 3, 12
24. How many times does a test suite run per day? Saturday, November 3, 12
25. What does it mean to add an extra test? Saturday, November 3, 12
26. Time Clarity Error Rate Saturday, November 3, 12
27. Tests can be legacy too Saturday, November 3, 12
28. The uncanny testing valley Saturday, November 3, 12
29. Too much testing to abandon, not enough testing to be confident Saturday, November 3, 12
30. Details Matter Saturday, November 3, 12
31. Why is refactoring part of the TDD cycle? Saturday, November 3, 12
32. Refactor Tests Saturday, November 3, 12
33. Some Test Refactorings Saturday, November 3, 12
34. Given When Then Setup Run Saturday, November 3, 12
35. Setup Saturday, November 3, 12
36. Apply Behavioral Name Saturday, November 3, 12
37. describe User do it "handles true input" do # ... end it "handles false input" do # ... end end Bad: Lazy Saturday, November 3, 12
38. describe User do describe "check_permissions" do it "validates permissions" do # ... end it "invalidates no permissions" do # ... end end end Better: Structure by Method Saturday, November 3, 12
39. describe User do describe "when checking for validations" do it "allows an admin user access" do # ... end it "denies a regular user access" do # ... end end end Best: Name by Behavior Saturday, November 3, 12
40. Extract test Saturday, November 3, 12
41. describe User do it "checks for validations" do user = User.new(:role => "admin") post = Post.new(:author => user) user.should be_able_to_see_post(post) user.role = "user" user.should be_able_to_see_post(post) post.author = User.new user.should_not be_able_to_see_post(post) end end Bad: Trying to do too much Saturday, November 3, 12
42. describe User do it "allows an admin to see a post" do user = User.new(:role => "admin") post = Post.new(:author => user) user.should be_able_to_see_post(post) end it "allows a user to see their own post" user = User.new(:role => "user") post = Post.new(:author => user) user.should be_able_to_see_post(post) end end Better: one at a time Saturday, November 3, 12
43. Extract setup Saturday, November 3, 12
44. describe User do it "allows an admin to see a post" do user = User.new(:role => "admin") post = Post.new(:author => user) user.should be_able_to_see_post(post) end it "allows a user to see their own post" user = User.new(:role => "user") post = Post.new(:author => user) user.should be_able_to_see_post(post) end end Bad: Duplicate Setup Saturday, November 3, 12
45. describe User do before(:each) do user = User.new(:role => "admin") post = Post.new(:author => user) end it "allows an admin to see a post" do user.should be_able_to_see_post(post) end it "allows a user to see their own post" user.should be_able_to_see_post(post) end end Better: Common setup Saturday, November 3, 12
46. Given Saturday, November 3, 12
47. Remove Extraneous Object Saturday, November 3, 12
48. describe User do it "finds users who have high ratings" do (1 .. 10).each do |rating| User.create(:rating => rating, :name => "User #{rating}") end User.high_rating.map(&:name).should =~ ["User 9", "User 10"] end end Bad: Too many objects Saturday, November 3, 12
49. Better: Just enough objects describe User do it "finds users who have high ratings" do high = User.create(:rating => 9) low = User.create(:rating => 8) User.high_rating.should =~ [high] end end Saturday, November 3, 12
50. Remove Database Creation Saturday, November 3, 12
51. Bad: Unnecessary DB hit describe User do it "finds users who have high ratings" do high = User.create(:rating => 9) low = User.create(:rating => 8) User.high_rating.should =~ [high] end end Saturday, November 3, 12
52. Better: No DB Hit describe User do it "finds users who have high ratings" do high = User.new(:rating => 9) low = User.new(:rating => 8) User.high_rating.should =~ [high] end end Saturday, November 3, 12
53. Remove default values Saturday, November 3, 12
54. describe User do it "finds users who have high ratings" do high = User.new(:rating => 9, :password => "test", :password_confirmation => "test", :username => "test", :email => "test@test.com") low = User.new(:rating => 8, :password => "test", :password_confirmation => "test", :username => "test", :email => "test@test.com") User.high_rating.should =~ [high] end end Bad: Lots of noise Saturday, November 3, 12
55. Better: Important stuff visible describe User do it "finds users who have high ratings" do high = Factory.build(:user, :rating => 9) low = Factory.build(:user, :rating => 8) User.high_rating.map(&:name).should =~ [high] end end Saturday, November 3, 12
56. When Saturday, November 3, 12
57. Separate actions Saturday, November 3, 12
58. Scenario: User logs in Given I am a logged in user When I hit my home page Then I see my profile When I go to edit my profile Then my profile is updated When I go to see my content Then my content is available Saturday, November 3, 12
59. Background: Given I am a logged in user Scenario: User logs in When I hit my home page Then I see my profile Scenario: User edits profile When I go to edit my profile Then my profile is updated Saturday, November 3, 12
60. Invoke the action at the right level Saturday, November 3, 12
61. Cucumber makes a lousy unit test framework Saturday, November 3, 12
62. Then Saturday, November 3, 12
63. Single Assertion Saturday, November 3, 12
64. describe "historical type behavior" do before(:each) do user.deals_for(:restaurant, 2, 5) deal.types << :restaurant end it "knows the pct of types for restaurant" do user.pct_bought_for(:restaurant).should == 0.4 end it "knows the score for each restaurant type" do user.history_score_for(:restaurant).should == 90 end end Single assertion Saturday, November 3, 12
65. Single test describe "historical type behavior" do it "calculates deal percentages" user.deals_seen_for(:restaurant, 2, 5) deal.types << :restaurant user.pct_bought_for(:restaurant).should == 0.4 user.history_score_for(:restaurant).should == 90 end end Saturday, November 3, 12
66. Test the right thing Saturday, November 3, 12
67. describe UserController do describe "get index" do it "searches properly" do @fred = User.create(:name => "Fred") @barney = User.create(:name => "Barney") get :index, :search => "Fred" assigns(:user).should == [@fred] end end end Saturday, November 3, 12
68. Assert Primitive Object Saturday, November 3, 12
69. describe User do it "searches properly" do @fred = User.create(:name => "Fred") @barney = User.create(:name => "Barney") result = User.search("Fred") result.should == [@fred] end end Using ActiveRecord in check Saturday, November 3, 12
70. describe User do it "searches properly" do @fred = User.create(:name => "Fred") @barney = User.create(:name => "Barney") result = User.search("Fred") result.map(&:name).should == ["Fred"] end end Using literal in check Saturday, November 3, 12
71. Switch to Spy Saturday, November 3, 12
72. var cheeseburger = { cheeses: function() { // Ajax call to cheese server }; }; it('spies on the cheese server', function() { spyOn(cheeseburger, 'cheeses'); cheeseburger.cheeses(); expect(cheeseburger.cheeses).toHaveBeenCalled(); }); Saturday, November 3, 12
73. Don't Assert Magic Literal Saturday, November 3, 12
74. it "averages ratings" do vendor.add_ratings(3) deal.regular_price = 16.00 deal.sale_price = 12.00 user.relevance_of(deal).should == 42.5 end Saturday, November 3, 12
75. it "averages ratings" do vendor.add_ratings(3) deal.regular_price = 16.00 deal.sale_price = 12.00 user.relevance_of(deal).should == (60 + (12.0 / 16)) / 2 end Saturday, November 3, 12
76. Complement Boolean Test Saturday, November 3, 12
77. Running Saturday, November 3, 12
78. Reduce Friction Saturday, November 3, 12
79. Display clearly Saturday, November 3, 12
80. After Saturday, November 3, 12
81. Listen to your tests Saturday, November 3, 12
82. Are all these tests still needed? Saturday, November 3, 12
83. Refactor Your Tests Saturday, November 3, 12
84. Don't Shortcut the Process Saturday, November 3, 12
85. Avoid the Uncanny Testing Valley Saturday, November 3, 12
86. What do programmers love? Saturday, November 3, 12
87. Developer testing is a means to an end Saturday, November 3, 12
88. @noelrap http://www.groupon.com/techjobs http://www.noelrappin.com/mstwjs RUBY_2012_25 Saturday, November 3, 12