Building and Scaling a Test Driven Culture

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

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

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

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

Artsy.net Website is [Relatively] Big
5534 Automated Tests
1h22m to Run / 6 Machines
http://art.sy/artwork/liu-di-animal-regulation-no-2
6

RSpec / BDD
“when X and Y it does X + Y”
 Data Models : ODM with real data
 Ruby API : HTTP request – response
 Integration : Capybara
7

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
8

Ruby API: 1894 Tests
it “create” do
expect {
post “/api/spline?name=test”
response.status.should == 201
}.to change(Spline, :count).by(1)
end
end
9

Integration: 1484 Tests
let(:spline) { Fabricate :spline }
it “displays a spline” do
visit “/spline/#{spline.id}”
page.should have_css “.spline[id=#{spline.id}]”
end
end
10

Building and Scaling a Test Driven Culture

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’
13

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

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

Successful Test Driven Culture
“It Works”

Signs of a Test Driven Culture

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 $

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

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

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

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

Building and Scaling a Test Driven Culture

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