Test-Driven Architecture

Transcript

1. Test-Driven Architecture Cherif BOUCHELAGHEM
2. Agenda - Architectural patterns - What about MVC? - Shared principles (between architectural patterns) - Test-Driven Development - The approach - Outside-In development - Demo (problem and code example)
3. architecturAL Patterns?
4. Architectural patterns Clean architecture - 2012 Functional core, imperative shell - 2012
5. Architectural patterns Onion architecture - 2008 Hexagonal architecture - 2005
6. What about MVC?
7. What about MVC? MVC is the half of the user menta model soure
8. What about MVC? MVC is the half of the user menta model DCI is the other half soure
9. What about MVC? Trygve Reenskaug James Coplien
10. Shared principles
11. Shared principles 1. Independent of Frameworks. 2. Testable. 3. Independent of UI. 4. Independent of Database. 5. Independent of any external agency.
12. Shared principles
13. Shared principles Ports, are contracts on the boundaries. Adapters, are implementations of the available ports to connect the app to the outside world.
14. Shared principles The outside world is anything that is not really important to solve the problem: Database, UI/HTTP/Graphql (Delivery mechanism), frameworks (Mobile, Web, … etc)
15. Shared principles
16. TDD
17. TDD traditional Cycle TDD Pyramid
18. About unit tests A test is not a unit test if: - It talks to a database - It communicates across the network - It touches the file system - You have to do things to your environment to run it (eg, change config files, comment line) - Tests that do this are integration tests.
19. About unit tests For isolation usually people talk about mocks, in reality mocks are one of the test doubles that help to to write unit tests: - Mock - Fake - Spy - Stub - Dummy
20. The approach
21. Outside-In Development with Double loop TDD
22. Outside-In Development with Double loop TDD Source
23. Outside-In Development with Double loop TDD 1. Write failing acceptance test for the application service behavior. 2. Write the application service code. 3. See the test fail. 4. Write failing microtest for domain model (core) code and see the test fail. 5. Write/design domain model code that makes the microtest pass. 6. At some point the same microtest exercise is needed to write contract tests for ports/interfaces adapters implementations . 7. Repeat 4 to 6 until the acceptance test pass.
24. Outside-In Development with Double loop TDD - Acceptance tests exercise domain model and infrastructure based on the acceptance criteria - Microtests exercise the domain model. - Contract tests exercise infrastructure ports & adapters implementations.
25. Outside-In Development with Double loop TDD
26. The problem
27. The problem Shopping cart rules: - The cart can not be orderable if it is empty - Item lines quantities are aggregated
28. The problem Shopping cart examples (acceptance criteria): - A new cart adds fried chicken, the output should say 1 fried chicken - A cart with fried chicken, it adds another fried chicken, the output should say there’s 2 fried chicken
29. Show me the code
30. References - https://blog.cleancoder.com/uncle-bob/2012/08/13/the-clean-architectu re.html - https://jeffreypalermo.com/2008/07/the-onion-architecture-part-1/ - https://web.archive.org/web/20180822100852/http://alistair.cockburn.u s/Hexagonal+architecture - https://jmgarridopaz.github.io/content/hexagonalarchitecture.html - https://www.destroyallsoftware.com/screencasts/catalog/functional-cor e-imperative-shell - https://coding-is-like-cooking.info/2013/04/outside-in-development-wi th-double-loop-tdd/ - https://netflixtechblog.com/ready-for-changes-with-hexagonal-architec ture-b315ec967749 -
31. References
32. Questions?