Talk given at AppNexus NYC, May 2013.

1. Building and Scaling
a Test Driven Culture
Engineering at Scale / AppNexus
Wednesday, May 8th 2013
@dblockdotorg
http://artsy.net
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2. Open Source FTW!

3. 1:0 Dev:Test
1124:1 Test:Code
http://www.sqlite.org/testing.html
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full automation
everybody tests
rock solid

4. some automation
some people test
some software doesn’t install
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2:1 Dev:Test
?:1 Test:Code

5. 5
full automation
continuous everything
8 hours of sleep per day
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1:0 Dev:Test
2:1 Test:Code

6. Artsy.net Website is [Relatively] Big
5534 Automated Tests
1h22m to Run / 6 Machines
http://art.sy/artwork/liu-di-animal-regulation-no-2
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7. RSpec / BDD
“when X and Y it does X + Y”
 Data Models : ODM with real data
 Ruby API : HTTP request – response
 Integration : Capybara
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8. Models = Mongo ODM + Fabricators: 2156 tests
context “spline” do
let(:spline) { Fabricate :spline }
it “reticulate! updates reticulated count” do
expect {
spline.reticulate!
}.to change(Spline.reticulated, :count).by(1)
end
end
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9. Ruby API: 1894 Tests
context “spline” do
it “create” do
expect {
post “/api/spline?name=test”
response.status.should == 201
}.to change(Spline, :count).by(1)
end
end
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10. Integration: 1484 Tests
context “spline” do
let(:spline) { Fabricate :spline }
it “displays a spline” do
visit “/spline/#{spline.id}”
page.should have_css “.spline[id=#{spline.id}]”
end
end
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12. 12
10x Everything

13. JavaScript: 960 Tests
Jasmine
beforeEach ->
view = new App.Views.UsersEdit
view.model = new App.Models.User fabricate ‘user’
describe ‘#save’, ->
it ‘saves the model’, ->
view.model.set ‘name’, ‘updated’
view.save()
JSON.parse(jqLastAjaxRequest.data).name.should equal ‘updated’
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14. JavaScript: Recent Projects
 Node – headless unit testing for client-side code
 Mocha – rspec-like testing
 Sinon – stub
 JSDom – simulate DOM API
 Zombie – headless browser integration testing

15. Test Driven Culture
 Tests are second nature
 A bug becomes a test becomes a fix
 A feature starts as a test becomes a feature
 Tests absorb developer stress
 Everyone has confidence in moving forward

16. Successful Test Driven Culture
“It Works”

17. Signs of a Test Driven Culture

18. Cost of Failure
 A very important demo with a potential investor
 A very important person using our site
 Hundreds of thousands of users
 You’re selling things for $

19. “To Be or Not to Be”

20. Testability

21. UI?

22. Ownership
https://groups.google.com/forum/?fromgroups=#!topic/ruby-grape/VELsU47wXkU
“It doesn’t work!”

23.  Management
 Money
 Consultants
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Don’t Count On Them

24.  Remove Those that Talk About Testing
 Hire From Open-Source
 Remove the Safety Net
 Use a Non-Compiling Language
 Do Devops
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Maintain a Test Driven Culture

25. @dblockdotorg
dblock@dblock.org
http://artsy.net
Thank You