Talk from WindyCityRails 2009

1. How To Test
Everything
Noel Rappin
Pathfinder Development

2. How To Test
Everything
... In Rails
Noel Rappin
Pathfinder Development

3. Guidelines

4. The First Guideline
Any change to the logic of the
program should be driven by a failed
test

5. The Second Guideline
A test should be as close as possible
to the associated code.

6. The Third Guideline
Test features and functionality, not
code

7. The Fourth Guideline
Rails works. (Mostly).
You don’t need to test it.

8. Framework

9. What Framework To
Use?

10. What Framework To
Use?
Short Answer: I don’t care

11. What Framework To
Use?
Short Answer: I don’t care
Longer Answer: Start with Rails Core,
move when you have an unfulfilled
need

12. What Framework To
Use?
Short Answer: I don’t care
Longer Answer: Start with Rails Core,
move when you have an unfulfilled
need
Those needs: Contexts, Factories,
Mocks

13. Models

14. Associations

15. Associations
No need to just check for the existence
of an association
Associations should be driven by
failing tests of actual functionality
Code extensions in an association
block should be treated like any other
code

16. Named
Scopes

17. Named Scopes
Named scopes are methods
Don’t test that a named scope has the
SQL decorations you put in
Do test that the scope correctly finds
or manages the objects you expect

18. Named Scope Tests

19. Named Scope Tests
assert_same_elements [@melvin, @thomas],
User.primary_status

20. Named Scope Tests
assert_same_elements [@melvin, @thomas],
User.primary_status
should_have_named_scope :primary_status do |u|
["online", "away"]include?(u.status)
end

21. Should Have Scope
def self.should_match_named_scope(named_scope,
*args, &block)
should "match named scope #{named_scope}" do
ar_class = self.class.model_class
scoped_objects = ar_class.send(named_scope, *args)
assert !scoped_objects.blank?
scoped_objects.each do |obj|
assert block.call(obj)
end
non_scoped_objects = ar_class.all - scoped_objects
assert !non_scoped_objects.blank?
non_scoped_objects.each do |obj|
assert !block.call(obj)
end
end
end

22. Validations

23. Validations
Don’t test Rails code
Do test for valid state
Do test anything custom
And anything with a regex
Failing saves can lead to irritating test

24. Controllers

25. Filters

26. Filters
Generally, test as part of actual action
Don’t need to re-test refactors
Failing filters are a big cause of silent
test failures

27. Views

28. Views
Test for semantic structure (DOM ID,
class)
assert_select is your friend
Sometimes, not test first

29. Test for the Negative
What’s not there is as important as
what is

30. Test for the Negative
What’s not there is as important as
what is
assert_select "#edit_link", :count => 0

31. Test for the Negative
What’s not there is as important as
what is
assert_select "#edit_link", :count => 0
assert_select "li:not(#edit_link)", :count => 2

32. Stupid assert_select
Tricks

33. Stupid assert_select
Tricks
assert_select "input[name *= phone]"

34. Stupid assert_select
Tricks
assert_select "input[name *= phone]"
assert_select "li#?", dom_id(@user, :item), :count => 1

35. Stupid assert_select
Tricks
assert_select "input[name *= phone]"
assert_select "li#?", dom_id(@user, :item), :count => 1
assert_select "ul#directory_list" do
assert_select "li:nth-of-type(1)",
:text => "Albert Aardvark"
assert_select "li:nth-of-type(2)",
:text => "Zack Zebra"
end

36. Helpers

37. Helpers
DO TEST HELPERS
Auto generated in Rails 2.3 and up
test/unit/helpers
Methods like url_for can be stubbed in
the test class
class UsersHelperTest < ActionView::TestCase
end

38. Testing Block Helpers

39. Testing Block Helpers
def if_logged_in
yield if logged_in?
end

40. Testing Block Helpers
def if_logged_in
yield if logged_in?
end
<% if_logged_in do %>
<%= link_to "logout", logout_path %>
<% end %>

41. Testing Block Helpers
def if_logged_in
yield if logged_in?
end
<% if_logged_in do %>
<%= link_to "logout", logout_path %>
<% end %>
test "logged_in" do
assert !logged_in?
assert_nil(if_logged_in {"logged in"})
login_as users(:quentin)
assert logged_in?
assert_equal("logged in", if_logged_in {"logged in"})
end

42. Testing Output
Helpers

43. Testing Output
def make_headline
Helpers
concat("<h1 class='headline'>#{yield}</h1>")
end

44. Testing Output
def make_headline
Helpers
concat("<h1 class='headline'>#{yield}</h1>")
end
test "make headline" do
assert_dom_equal("<h1 class='headline'>fred</h1>",
make_headline { "fred" })
end

45. Testing Output
def make_headline
Helpers
concat("<h1 class='headline'>#{yield}</h1>")
end
test "make headline" do
assert_dom_equal("<h1 class='headline'>fred</h1>",
make_headline { "fred" })
end
test "make headline with output buffer" do
make_headline { "fred" }
assert_dom_equal("<h1 class='headline'>fred</h1>",
output_buffer)
end

46. assert_select helpers

47. assert_select helpers
setup :setup_response
def setup_response
@output_buffer = ""
@request = ActionController::TestRequest.new
@response = ActionController::TestResponse.new
end
def make_response(text)
@response.body = text
end

48. assert_select helpers
setup :setup_response
def setup_response
@output_buffer = ""
@request = ActionController::TestRequest.new
@response = ActionController::TestResponse.new
end
def make_response(text)
@response.body = text
end
test "make headline with response body" do
make_headline { "fred" }
make_response output_buffer
assert_select("h1.headline")
end

49. Email

50. Email
ActionMailer::Base.deliveries.clear
Treat emails like views
assert_select_email
email_spec plugin for Cucumber &
RSpec
Shoulda: assert_did_not_sent_email,
assert_sent_email

51. Email
ActionMailer::Base.deliveries.clear
Treat emails like views
assert_select_email
email_spec plugin for Cucumber &
RSpec
Shoulda: assert_did_not_sent_email, do
should "send an email to mom"
assert_sent_email assert_sent_email do |email|
email.to == "mom@mommy.com"
end
end

52. User
Interaction

53. Multi-User Interaction
Integration tests
test "user interaction" do
my_session = open_session
your_session = open_session
my_session.post("messages/send", :to => you)
your_session.get("messages/show")
assert_equal 1, your_session.assigns(:messages).size
end

54. Ajax

55. Ajax
assert_select_rjs, but only for Rails
stuff
test "an ajax call"
xhr get :create
assert_select_rjs :replace, :dom_id, 12
end

56. Blue Ridge /
Screw.Unit
Screw.Unit(function() {
describe("With my search box and default", function() {
it("should switch the default", function() {
search_focus($('#search'));
expect($('#search').attr('value')).to(equal, '');
});
});
});

57. External Sites

58. Third Party Sites/ Web
Mock, Mock, Mock, Mock
Encapsulate call into an easily-mocked
method
Remember to test failure response

59. Rake

60. Rake Tasks
Encapsulate the task into a class/
method and test that method

61. Rake Tasks
Encapsulate the task into a class/
method and test that method
test "my rake task" do
@rake = Rake::Application.new
Rake.application = @rake
Rake.application.rake_require "lib/tasks/app"
Rake::Task.define_task(:environment)
@rake[:task_name].invoke
end
http://
www.philsergi.com

62. Dates and
Time

63. Date/Time
Timecop

64. Date/Time
Timecop
setup :timecop_freeze
teardown :timecop_return
def timecop_freeze
Timecop.freeze(Time.now)
end
def timecop_return
Timecop.return
end

65. Date/Time
Timecop
setup :timecop_freeze
teardown :timecop_return
def timecop_freeze
Timecop.freeze(Time.now)
end
def timecop_return
Timecop.return
end
Timecop.freeze(Date.parse('8 April 2009').to_time)

66. File Upload

67. File Uploads
fixture_file_upload
post :update,
:image => fixture_file_upload(
'/test/fixtures/face.png', 'image/png')

68. Rack
Rails Metal

69. Rails Metal
Rack Middleware
Integration tests and cucumber
Rack::Test
def test_redirect_logged_in_users_to_dashboard
authorize "bryan", "secret"
get "/"
follow_redirect!
assert_equal "http://example.org/redirected",
last_request.url
assert last_response.ok?
end

70. Legacy
Applications

71. Legacy Apps
Acceptance is the first step
Make sure the suite runs
Try black-box tests
Try mock objects
Look for seams
Don’t look backward

72. Wrap Up

73. Wrap Up
Code should flow from failed tests
Test features and functionality
Look for tools to help
The goal is great code that delivers
value

74. For More Info
http://speakerrate.com/events/183
http://www.pathf.com/blogs
http://blog.railsrx.com
http://www.twitter.com/noelrap
http://www.pragprog.com/titles/