Testing microservices in node.js

Microservice architecture is becoming an increasingly popular choice among platform architects, and for good reason: when implemented correctly, it can increase team velocity, facilitate technological diversity, and enforce good abstractions. However, writing good tests for a microservice-based platform is often a tough task, due to the complexity of the interactions between services and of the system as a whole.

In this talk, Justin will present an introduction to microservice architecture, as well as an overview of the various types of automated test suites and their place in conventional application development. He will then discuss the role of each type of test in the context of microservice-based systems, and will close with a number of recommendations for writing efficient and effective tests. Along the way, Justin will highlight various JavaScript tools that are helpful when writing tests for Node.js applications and microservices.

Transcript

1. Justin Bachorik 11.2.2018 Testing microservices in node.js
2. justinbach A little bit about me @justinbach on GitHub and Twitter
3. justinbach A little bit about Capital One
4. justinbach What we’ll cover 1. Testing: why and how? 2. Overview of microservice architecture 3. Testing microservices in node.js
5. justinbach Testing
6. justinbach Thought experiment #1
7. justinbach
8. justinbach Reasons to test
9. justinbach It’s all about the users!
10. justinbach A “classical” testing taxonomy
11. justinbach Unit tests
12. justinbach Failing unit tests as bug reports 1. Which component is being tested? 2. What behavior is being tested? 3. What are the actual results? 4. What are the expected results? 5. How can the actual results be reproduced? https://medium.com/javascript-scene/what-every-unit-test-needs-f6cd34d9836d
13. justinbach Integration tests
14. justinbach Functional tests
15. justinbach Other ways of classifying tests
16. justinbach Google’s small, medium, and large tests https://testing.googleblog.com/2010/12/test-sizes.html
17. justinbach White-box and black-box tests
18. justinbach Microservices
19. justinbach Thought experiment #2
20. justinbach
21. justinbach
22. justinbach Backend duties • User management • Dog inventory • Walk scheduling • Business reporting • Notifications • Client app API • Business API
23. justinbach Congrats, you’ve built a monolith! Wikimedia Commons
24. justinbach Puppies Microservices to the rescue! kitty.green66 / Flickr
25. justinbach
26. justinbach User management Dog inventory Walk scheduling Reporting Notifications
27. justinbach Advantages of microservices • Separation of concerns • Smaller, faster deployments • Technological heterogeneity • Resilience See https://martinfowler.com/articles/microservice-trade-offs.html for more
28. justinbach Microservices: Infrastructural tooling
29. justinbach Microservices: CI/CD pipeline
30. justinbach Microservices: Backends for frontends iPhone API Dog inventory Scheduling Tablet API Partner API
31. Justin Bachorik 11.2.2018 Testing microservices in node.js
32. justinbach A sample route GET /dogs [{ name: “Biscuit”, id: “df724ea3-beb8-4c97-a6a5-32acaba7bbad”, photo: “https://cdn.dogpool.com/img/b87f8fcd.jpg” }, // … more dogs? ]
33. justinbach Route topology Public API Auth Dogs GET /dogs Dog data
34. justinbach Route sequence diagram
35. justinbach Unit tests Dogs
36. justinbach Unit tests dog.js findByUserId() SQL rows
37. justinbach Method under test const findByUserId = async (db, userId) => { if (!userId) { throw new Error('findByUserId: must specify userId'); } return db.query(Sql.FIND_BY_USER, userId); };
38. justinbach Example: unit test describe('findByUserId', () => { it('should return dogs belonging to the user', async () => { await insertTestData(db, expectedData); // arrange const actualData = await Dog.findByUserId(db, userId); // act expect(actualData).to.deep.equal(expectedData); // assert await reset(db); }); });
39. justinbach Unit tests... • ...exhaustively test methods, one code-path at a time • ...live alongside the code under test • ...are run on every commit and PR • ...tend to be more white-box than other tests
40. justinbach Unit tests: tools 1. Testing framework (Mocha, Jest, Jasmine, Ava, Tape) 2. Assertion library (Assert, Should, Expect, Chai) 3. Mocking plugin (Sinon) 4. Coverage reporter (Istanbul, NYC)
41. justinbach Service integration tests Dogs GET /dogs?userId=... Dog data
42. justinbach Service integration tests... • ...exercise the full request cycle at the microservice level • ...validate routing and middleware configuration • ...are run on every commit and PR • ...are gray-box (requests to upstream services are mocked)
43. justinbach Service integration tests: tools All of our unit testing tools, plus Supertest!
44. justinbach Example: service integration test describe('GET /dogs?userId={userId}', () => { it('should return 200 and the correct dogs', async () => { const actualResponse = await request(app) .get(`/dogs?userId=${userId}`) .expect(200); expect.actualResponse.to.deepEqual(expectedResponse); }); });
45. justinbach Platform integration tests Public API Auth Dogs GET /dogs Dog data
46. justinbach Platform integration tests... • ...can reside in Public API or an external repository • ...are run against a full staging environment • ...are completely black-box (except external service mocks)
47. justinbach 1. Testing framework (Mocha, Jest, Jasmine, Ava, Tape) 2. Assertion library (Assert, Chai, Should, Expect) 3. Request library (request-promise, fetch) 4. Service-mocking tool (WireMock) Platform integration tests: tools
48. justinbach Example: platform integration test describe('GET /dogs', () => { it('should return the current user’s dogs', async () => { const options = { method: 'GET', url: `${host}/dogs`, headers: `Bearer ${token}` }; const actualResponse = await rp(options); expect.actualResponse.to.deepEqual(expectedResponse); }); });
49. justinbach Extra credit: E2E tests Public API Authz Dogs GET /dogs Dog data
50. justinbach So, to recap... Unit tests Service integration tests Platform integration tests E2E tests
51. justinbach Thank you! Questions? justin.bachorik@capitalone.com