Living with acceptance tests: Beyond Write-Once (XP NYC)

Living with
Acceptance Tests:
Beyond Write-Once
Daniel Wellman
Twitter: @wellman
E-mail: dan@danielwellman.com
www.intentmedia.com
XP NYC #xpnyc
February 10, 2015

Goal
Build the least helpful,
most frustrating
acceptance test suite

Revise Your Tests
With the Same Care as
Your Production Code

Server
Database QueueTest
End-to-End Tests

New Project
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test
End-to-End
Acceptance Test

Institutionalized
Response to
Failure

Run Acceptance
Tests in Parallel

Don’t make every
acceptance test run
end-to-end

Ports and Adapters
a.k.a. Hexagonal Architecture

Adapters
Ports
Domain
GUI
DB
Memory
End-to-End Test
Test Using
Domain

Example: Fraud Protection
for an Amazon-like store
Example from Gojko Adzic, “Specification by Example”
Given a user with no previous transaction history,
And the user’s account registration country is the UK,
When the user places an order with delivery country U.S.,
Then the transaction is marked as suspicious,
But the user sees order status as “Pending.”

Before: End-to-End
When(/^the user places an order with
delivery country (.*),$/) do |country_name|
end
# ...
fill_in 'Address', with: ...
select country_name, from: 'Country Selector’
click_button 'Ship To This Address'
expect(page).to have_content
'Your order has been placed’
# ...

After: Using Domain Model
end
# ...
country = Country.new(country_name)
order = Order.new( ...,
ship_to : Address.new(
street: ...,
country: country))
sales_clerk.accept(order)
# ...

Service
UI
Unit
The Testing Pyramid

Create a Separate
System Test Suite

Alternate Step
Implementations

Alternate Steps:
Use Conditionals
if use_browser
# drive a browser using Capybara; slower
else
# use domain objects; faster
end
end
use_browser = ENV['USE_BROWSER_FOR_TESTS']

Write Tests
Without Specifying
Implementation Details

Imperative
vs.
Declarative
Style

Imperative Style
Given I am on the registration page,
And I enter "UK" as my billing country,
And I press the "Register" button,
And I add an item to my cart,
When I checkout
And I enter "U.S." as my shipping country,
And ...

Declarative Style
Given a user with no previous transaction history,
And the user’s account registration country is the UK,
When the user places an order with delivery country U.S.,
Then the transaction is marked as suspicious,
But the user sees order status as “Pending.”
Example by Gojko Adzic, “Specification by Example”
You can’t tell how these are implemented!

Use Declarative Style
to Help Keep
Implementation
Details Out
of Tests

Problem: I’m not sure
what is actually
tested…

Periodically
Evaluate
Your
Test Suite

Have you introduced a
new domain concept?

Are you in a new stage
of your product’s life?

Suggestions
• Maintain your acceptance tests just like production
code
• Write tests which describe what, not how, so their
implementations can easily evolve later
• Decide when you can start moving acceptance
tests from end-to-end to using the domain directly
• Re-evaluate your product’s tests and testing
strategy as your system grows

Photo Credits
“HighLine_061409_2779” by Jessica Sheridan is licensed under CC BY 2.0
“Highline New York” by Rebecca Krebs is licensed under CC BY 2.0
“NYC: The Highline" by Wally Gobetz is licensed under CC BY-NC-ND 2.0
“Rot”, “Yellow Cart”, and “Many Hands Make Light Work” by Oliver Rich are licensed
under CC BY-NC-ND 2.0
“highline-1010384.jpg” by keroism is licensed under CC BY-SA 2.0
“highline” by Elijah Porter is licensed under CC BY-NC-SA 2.0
“Highline_030” by Timothy Vogel is licensed under CC BY-NC 2.0
“201106073451_DSC_0014_1.JPG” by Leonel Ponce is licensed under CC BY-NC 2.0
“193” by verndogs is licensed under CC BY-NC 2.0

Living with acceptance tests: Beyond Write-Once (XP NYC)

More Related Content

What's hot

Viewers also liked

Similar to Living with acceptance tests: Beyond Write-Once (XP NYC)

Recently uploaded

Living with acceptance tests: Beyond Write-Once (XP NYC)

Editor's Notes