Post on 12-May-2015
description
BDD for APIs
Jason Harmon
Jason Harmon• Blogger on apiux.com• API Architect @uShip
• Likes Python• Works in everything else
• Funny mustache• Loves weiner dogs
Some things to keep in mind…About 80s movies/tv
and software
Humans > Robots
Terminator taught us…
Agile
• INDIVIDUALS AND INTERACTIONS over processes and tools–Inside our organization and with our
users
Automationcan
be ourfriend too
Johnny Fivetaught us…
Agile
• WORKING SOFTWARE over comprehensive documentation–Not only in our product but our
testing & regression
Sometimesthere isno timeto plan
Always havea plan
Agile
• RESPONDING TO CHANGE over following a plan– APIs will change for your business,
better have tests
Work together!
Agile
• CUSTOMER COLLABORATION over contract negotiation– Get good at sharing ideas
What is BDD?
• “Behavior Driven Development”• English readable description of how our product
behaves• Agreed upon by the team: not Dev, QA or
product owned• Used to verify the acceptance criteria for
features in a product• Conceptually like TDD (test-first), but for
functional testing (not code architecture)
* Agile Testing: A Practical Guide for Testers and Agile Teams (Addison-Wesley, 2009)
http://lisacrispin.com/2011/11/08/using-the-agile-testing-quadrants/
Q2 Automated & Manual Tests
Functional TestsExamplesStory TestsPrototypesSimulations
Supp
ortin
g th
e Te
amBusiness Facing
BDD
Polyglot friendly
• Cucumber– Ruby-based, the granddaddy of BDD
• Cucumber-JVM– Java implementation, plays nice with Junit and all JVM
languages (Groovy is quite nice here)• Specflow
– .NET, Visual Studio integrated• Lettuce
– Python-based, very similar to Cucumber• Behat
– PHP-based
GherkinOne Description to Rule Them All
• https://github.com/cucumber/gherkin • Business Readable• DSL• Not code
Gherkin ExampleImperative Style
Scenario: Get nearby place nameGiven I use the geonames hostWhen I access the resource url
"/findNearbyPlaceNameJSON" And I provide parameter "username" as "jharmon" And I provide parameter "lat" as "30.4754724" And I provide parameter "lng" as "-98.1564068"
And I retrieve the JSON resultsThen the status code should be 200And it should have a list "geonames"And the list should have at least 1 item
Gherkin ExampleDeclarative Style
Scenario: Get nearby place nameGiven I use the geonames hostWhen I use the “Find Nearby Place by JSON” endpoint
And I identify my “geonames” user credentials And I provide coordinates 30.4754724, -98.1564068
And I retrieve the JSON resultsThen it should have at least 1 valid "geonames" item
Behavior Driven
• User experience trumps all• API is no exception• Treat API consumers like first class citizens• Describe how your API behaves from a
consumer perspective
Step Definitions
Scenarios“…until it’s green like a cuke”
Scenario outlines
ErrorsRed means stop
Tags
Lots of power to selectively run groups of tests
DEVE
LOPE
RS
TEST
ERS
STAK
EHOL
DER
S
PROD
UCT
Agreement
• Decide during planning how you will test for Acceptance Criteria
• …AS A TEAM…• Gherkin/feature definitions will allow a
ubiquitous language• Technically, this can get easier as the critical
mass of your API interactions is in your testing framework, and scenario steps are predictable
Productivity
• Stakeholders know what they’re getting• Devs know how to build it• Testers know how to test it• Product knows how to sign off• Documentation has a head start
Prod
uct
Dev
elop
ers
Test
ers
Stak
ehol
ders
Real world silos teach us…
Humans die inside silos!!!
Domain Language
• Focus on how you describe everything• Find agreement on how to describe behavior• Recognize when behavior is different than
before– “Wait, we’ve never deleted before!”
• Homework: Domain Driven Design
Share!
• All BDD tests can be committed to SCM, including branches
• Provide process which allows collaborative coding on building test framework
• Devs provide expertise on building a scalable test framework
• Testers utilize existing step definitions to quickly build out tests
Continuous Integration
• Regression is running all the time• Use tags to select the right depth of regression• Very fast identification of what’s broken
Samples
• Python/Lettuce– https://github.com/jasonh-n-austin/api-bdd-tests
• Groovy/Cucumber-JVM– https://github.com/jasonh-n-austin/TwitterRestTests
• .NET/SpecFlow– https://github.com/jasonh-n-austin/TwitterRestTests