Did you ever struggle consuming an API that kept on changing? Did you provide an API that you were unsure how people will use it? In such a scenario, an iterative and cooperative way of working that focuses on consumer driven contract testing can reduce your pain. In other words, an experience with “Consumer collaboration over contract negotiation”. This talk aims to practically illustrate consumer driven testing using Pact. We will cover when this technique is appropriate and how to organise, define and evolve APIs while keeping in mind. The session will involve a mixture of presentation and live coding to illustrate on how this works in practice. https://europeantestingconference.eu/2020/topics/#matteo-pierro Talk with https://twitter.com/matteo_pierro

1. CONSUMER DRIVEN CONTRACT
TESTING WITH PACT
The evolution of your APIs supporting with
tests
@nelisboucke @matteo_pierro

2. Overview
● Why?
● What is Contract Testing?
● Code example with Pact
● Challenges

3. Overview
● Why?
● What is Contract Testing?
● Code example with Pact
● Challenges

4. A STORY…

5. A STORY…

6. NOT COVERED BY TESTS?
Trustworthy
Cheap TargetedReliable

7. Integration tests
Use running
system
Use mocks
Reliability - +
Speed - +
Targeted - +
Environment setup - not needed
Test data - +
Easy to automate - +
Trustworthy + -

8. IF ONLY WE COULD VERIFY THE MOBILE
TEAM'S MOCKS ……..

9. Overview
● Why?
● What is Contract Testing?
● Code example with Pact
● Challenges

10. Contract Testing flow →

12. Overview
● Why?
● What is Contract Testing?
● Code example with Pact
● Challenges

13. E-commerce →

15. Code Example →

16. Overview
● Why?
● What is Contract Testing?
● Code example with Pact
● Challenges

17. Challenge: collaboration?
PACT does not solve your collaboration problems
● Provider must verify consumers’ expectations
● Consumer must check expectations with the provider

18. Challenge: Rework?
PACT replaces your previous mocks
● Rework / Extend consumer tests to for this

19. Challenge: When Applicability?
● You want to integrate fast
○ Evolving application
○ Fast feedback
○ Reduce integration risk
● Limited and known consumers
○ Typical settings
■ Single organisation, multiple teams
■ Frontend backend
■ Microservices

20. @matteo_pierro@nelisboucke
Questions?