Possiamo fidarci dei nostri Unit Test?

Un vantaggio del paradigma FaaS è la possibilità di immaginare un sistema come cooperazione di funzioni indipendenti, coordinate da contratti ben definiti: romperne anche solo uno potrebbe compromettere l'intero sistema, oltre a minarne l'agilità di evoluzione. Basteranno degli unit test a salvarci?

Transcript

1. POSSIAMO ANCORA FIDARCI DEI NOSTRI UNIT TEST? Mariano Calandra • 4 giugno 2020 • ServerlessDays Italy
3. THE MONOLITH “ “when all functionality in a system had to be deployed together […]”
4. BREAK THE MONOLITH EVERYBODY WANTS TO
5. BREAK THE MONOLITH EVERYBODY WANTS TO BUT…
6. Simply development workflow PROS Easy to deploy Straight monitoring Code reuse (within the monolith) Single process
7. CONS Low modularity Delivery contention Technical debt All or none Coupling (implementation and deployment)
8. MICROSERVICES “ “small, autonomous services that work together”
9. PROS Modeled around business domain Own their own data Process isolation High modularity Independent (implementation & deploy)
10. CONS No distributed transactions* Steep learning curve E2E is not trivial …but above all Distributed system’s issues (*) I’m not sure if this is a real problem J
11. …CHATTINESS “ “communication overhead increases because microservices have to talk to each other”
12. Orders
13. POST /orders Orders
14. Does this customer exist? Orders POST /orders
15. Does this customer exist? Orders POST /orders Is this address correct?
16. Orders POST /orders
17. Orders POST /orders Add the order_id property
18. Orders POST /orders Add the timestamp property Add the order_id property
19. order_confirmed Orders POST /orders
20. ORDERS SERVICE
21. ORDERS SERVICE
22. UNIT TEST 1
23. UNIT TEST 2
24. POST /orders order_confirmed makeEvt(…) ~100% CODE COVERAGE
25. POST /orders order_confirmed Orders ListOfOrders makeEvt(…)
26. POST /orders order_confirmed Orders ListOfOrders makeEvt(…) validateEvt(…)
27. POST /orders order_confirmed Orders ListOfOrders makeEvt(…) validateEvt(…) Is this type correct?
28. POST /orders order_confirmed Orders ListOfOrders makeEvt(…) validateEvt(…) Does this customer_id exist? Is this type correct?
29. POST /orders order_confirmed Orders makeEvt(…) validateEvt(…) ~100% CODE COVERAGE
30. The property is called customer_id but it contains a username. It would be better to rename it! RefactorTrooper ARE WE SAFE?
31. Orders (v2) makeEvt(…)
32. Orders (v2) makeEvt(…) REFACTORING
33. Orders (v2) makeEvt(…) REFACTORING UNIT TEST
34. Orders (v2) makeEvt(…) REFACTORING UNIT TEST
35. Orders (v2) makeEvt(…) REFACTORING UNIT TEST DEPLOY
36. SEE YOU TOMORROW…
37. POST /orders Orders (v2) makeEvt(…)
38. POST /orders order_confirmed Orders (v2) publish(evt)
39. POST /orders order_confirmed Orders (v2) publish(evt) ListOfOrders validateEvt(…)
40. POST /orders order_confirmed Orders (v2) publish(evt) ListOfOrders validateEvt(…) Does this customer_id exi…
41. POST /orders order_confirmed Orders (v2) publish(evt) ListOfOrders validateEvt(…) Does this customer_id exi…
42. CAN WE STILL TRUST OUR UNIT TEST?
43. ListOfOrders YES WE CAN, BUT… Orders
44. ListOfOrders Orders 100% CODE COVERAGE 100% CODE COVERAGE ...EVEN THOUGH
45. ListOfOrders Orders 100% CODE COVERAGE 100% CODE COVERAGE WE ARE FAR FROM BEING 100% SAFE …EVEN THOUGH
46. THE WHOLE IS GREATER THAN T H E S U M O F ITS PARTS
47. ListOfOrders (consumer) Orders (producer) THE PARTS
48. ListOfOrders (consumer) Orders (producer) THE WHOLE order_confirmed
49. ListOfOrders (consumer) build a contract CONSUMER DRIVEN CONTRACT TESTING
50. ListOfOrders (consumer) build the contract A JSON file with the consumer’s expectations
51. CONSUMER TEST
52. CONSUMER TEST
53. CONSUMER TEST
54. CONSUMER TEST
55. PROVIDER TEST
56. PROVIDER TEST
57. PROVIDER TEST
58. Orders (v2) (provider) validate against the consumer’s expectations
59. Orders (v2) (provider) validate against the consumer’s expectations
60. TAKE AWAY CDCT for testing external behaviour Communication is a contract Unit test for testing internal behaviour Why unit testing is not enough when it comes to microservice (medium.com) Code sample (github.com) Further reading What about serverless?
61. Passionate about microservices and serverless AWS Authorized Instructor ServerlessDays Rome co-organizer Work in Claranet Italia (formerly known as XPeppers) MARIANO CALANDRA I AM
62. NO BRICKS WERE HARMED…
63. Sam Newman – Monolith to microservices, O’Reilly, 2019 REFERENCES Sam Newman – Building microservices, O’Reilly, 2015 Whitepaper – Microservices on AWS
64. Images – unsplash.com CREDITS Icons – icons8.com Templates – powerpointify.com