Agile Software Testing - Agilogy - Voxel.pdf

Agile software development patterns and strategies for the busy agile software developer.

1. Agile Automated Testing
Jordi Pradel

2. Jordi Pradel Miquel
Software developer
Interested in agility, quality, backend,
functional programming, ...
- 2005: Founder of Agilogy
- 2014, 2016: Father of 2
- 2020: Amateur violinist

3. Agile software testing
Goals
Desiderata
Technical concepts
Patterns
Strategy

4. Goals
No Bugs!
detection & prevention

5. Desiderata

6. Principles
•Usability to better testing!
•Determinism !
•Welcoming to change !
•User friendliness !
•Quality, quality, quality!
•Economy !

7. Deterministic tests
Flaky tests
Avoid. Flaky. Tests.

8. Deterministic tests
Isolate tests from
•Execution order
•Concurrency
•External systems
•The alignment of stars

9. Tests that (allow you to) welcome change
Don't be in the way of refactoring
outcome, not behavior
Changes, changes, changes!
cohesion

10. User friendly tests
•Clear error reporting
•Fast!
•Maintainable test code

11. Economics of testing
•How to prioritize?
•How to design?

12. Technical concepts
(aka buzzwords)

13. Black box vs white box

14. Broad stack tests
vs
Narrow tests

15. Test doubles
Dummy
Fake
Mocks, stubs and spies

16. Mocks vs Spies
Stubs

17. Unit tests
developer-centric
small
fast
https://martinfowler.com/bliki/UnitTest.html

18. Integration tests

19. A very gentle
introduction to
Hexagonal
Architecture

20. Hexagonal architecture
Application
(domain)
driven sidedriving side
Driving
adapter
Driving
adapter
Driven
adapter
Driven
adapter
Driving
port
Driving
port
Driven
port
Driven
port
(aka Controllers)
(aka use cases / services)
(aka repository / api proxy
interfaces)
(aka repository / api proxy
implementations)

21. Hexagonal architecture
Example
Application
(domain)
driven sidedriving side
RulesEngineController
RulesEngineRepository
VppApiProxy
RulesEngineService
IRulesEngineRepository
IVppApiProxy
VppApi
Payments
(PostgreSql)

22. Driving adapters
(aka controllers)
•Low level implementation of APIs, listeners, etc to get commands, queries
or events from the outside to the driving ports in the hexagon.

23. Driving adapters (controllers)
Dependency Injection

24. Driving ports
(aka services, use cases, interactors)
•Domain interface of the app used by the driving adapters to pass
commands, queries and events in the language of the domain.

25. Driven ports
(aka repositories, api proxies)
•Domain abstraction of the capabilities of external systems used by the
application.

26. Driven adapters
(aka data sources)
•Low level implementation of the interfaces of driven ports that use
specific external services or technologies (e.g. a PostgreSql database).

27. Driven Adapters
Decouple driven ports from technology used: Exceptions
!

28. Patterns

29. Arrange, Act, Assert
Stateless components

30. AAA with state
Stateful components
1. Arrange inputs & initial state
2. Act
3. Assert outputs & final state
https://blog.agilogy.com/2022-06-17-testing-and-persistent-state.html

31. In-memory
production-ready
test fakes
" fast!
" deterministic
# may fail
# implementation cost

32. In-memory production-ready test fakes
Alternatives
•Test in integration with Isolated, production(-like) external systems
•" You test the actual component
•# Slow
•Use mocks and stubs
•# You test the behaviour of the system, not the outcome

33. Isolated,
production(-like)
external systems
" real
# slow

34. Strategy

35. Test all the domain
Broad test of all the components that
form the domain
•Whole domain
•Through (driver) ports (controllers)
•Use AAA with state

36. A.Test with In-memory,
production-ready test fakes
(preferred)
B.Test in integration with
Isolated, production(-like)
external systems (slower)
Test all the domain
alternatives

37. Narrow tests of
complex logic
•unit tests
•AAA / AAA with state
•only a bunch of these!

38. Integration tests of
driven adapaters
•integration tests
•isolated, production-like
external systems
•in isolation
•AAA with state

39. Test Driver
Adapters
A.behavior with Mocks and
stubs
B.outcome with the actual
domain + doubles

40. Test the assembly with end-to-
end tests

41. Test test fakes
Make In-memory, production-ready
tests fakes production-ready indeed:
•Parameterize Integration tests
•Run the same test suite for both

42. Invest!
A couple examples...

43. Clear error
reporting

44. Property-based
testing with shrinking

45. Property-based testing with shrinking