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Justin Bachorik 11.2.2018 Testing microservices in node.js

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justinbach A little bit about me @justinbach on GitHub and Twitter

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justinbach A little bit about Capital One

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justinbach What we’ll cover 1. Testing: why and how? 2. Overview of microservice architecture 3. Testing microservices in node.js

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justinbach Testing

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justinbach Thought experiment #1

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justinbach Reasons to test

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justinbach It’s all about the users!

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justinbach A “classical” testing taxonomy

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justinbach Unit tests

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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

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justinbach Integration tests

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justinbach Functional tests

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justinbach Other ways of classifying tests

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justinbach Google’s small, medium, and large tests https://testing.googleblog.com/2010/12/test-sizes.html

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justinbach White-box and black-box tests

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justinbach Microservices

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justinbach Thought experiment #2

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justinbach Backend duties • User management • Dog inventory • Walk scheduling • Business reporting • Notifications • Client app API • Business API

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justinbach Congrats, you’ve built a monolith! Wikimedia Commons

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justinbach Puppies Microservices to the rescue! kitty.green66 / Flickr

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justinbach User management Dog inventory Walk scheduling Reporting Notifications

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justinbach Advantages of microservices • Separation of concerns • Smaller, faster deployments • Technological heterogeneity • Resilience See https://martinfowler.com/articles/microservice-trade-offs.html for more

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justinbach Microservices: Infrastructural tooling

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justinbach Microservices: CI/CD pipeline

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justinbach Microservices: Backends for frontends iPhone API Dog inventory Scheduling Tablet API Partner API

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Justin Bachorik 11.2.2018 Testing microservices in node.js

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justinbach A sample route GET /dogs [{ name: “Biscuit”, id: “df724ea3-beb8-4c97-a6a5-32acaba7bbad”, photo: “https://cdn.dogpool.com/img/b87f8fcd.jpg” }, // … more dogs? ]

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justinbach Route topology Public API Auth Dogs GET /dogs Dog data

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justinbach Route sequence diagram

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justinbach Unit tests Dogs

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justinbach Unit tests dog.js findByUserId() SQL rows

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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); };

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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); }); });

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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

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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)

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justinbach Service integration tests Dogs GET /dogs?userId=... Dog data

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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)

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justinbach Service integration tests: tools All of our unit testing tools, plus Supertest!

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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); }); });

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justinbach Platform integration tests Public API Auth Dogs GET /dogs Dog data

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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)

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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

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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); }); });

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justinbach Extra credit: E2E tests Public API Authz Dogs GET /dogs Dog data

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justinbach So, to recap... Unit tests Service integration tests Platform integration tests E2E tests

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justinbach Thank you! Questions? [email protected]