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mocking for fun and profit APIs #confoo 2020 @ruyadorno

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Ruy Adorno OSS Dev @ @ruyadorno

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#confoo 2020 @ruyadorno ToC 1. Naming 2. Testing 3. Microservices 4. Front-End 5. Tooling

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so, about naming… MOCKS == STUBS #confoo 2020 @ruyadorno in the context of this talk:

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before we #confoo 2020 @ruyadorno start

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Have you been mocking lately? #confoo 2020 @ruyadorno

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#confoo 2020 @ruyadorno How many people back-end work in an env with front-end teams? separated

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TESTS #confoo 2020 @ruyadorno

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Mocks are most popular for their usage within tests #confoo 2020 @ruyadorno

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•Abstract away complexity •System-specific APIs •Help coverage Mocks in the context of tests: #confoo 2020 @ruyadorno

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#confoo 2020 @ruyadorno Talking about abstracting away complexity…

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#confoo 2020 @ruyadorno

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#confoo 2020 @ruyadorno

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#confoo 2020 @ruyadorno

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Mocking APIs sounds like a Great idea! #confoo 2020 @ruyadorno

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#confoo 2020 @ruyadorno Test framework example…

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Patch APIs #confoo 2020 @ruyadorno import { API } from './api' it(‘retrieves API data', () => { API.get = () => ({ data: ‘12345’ }) API.get(‘something’) .then(res => { expect(res.data) .toEqual(‘12345') }) })

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npm.im/jest #confoo 2020 @ruyadorno import { API } from './api' jest.mock(‘./api’, () => { API: () => ({ data: ‘12345’ }) } it(‘retrieves API data', () => { API.get(‘something’) .then(res => { expect(res.data) .toEqual(‘12345') }) })

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npm.im/jest-fetch-mock #confoo 2020 @ruyadorno import { API } from './api' it(‘retrieves API data', () => { fetch.mockResponseOnce( JSON.stringify({ data: ‘12345' }) ) API.get(‘something’) .then(res => { expect(res.data) .toEqual(‘12345') }) })

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npm.im/nock #confoo 2020 @ruyadorno import { API } from './api' const nock = require('nock') it(‘retrieves API data', () => { nock('http://www.example.com') .get('/something') .reply(200, '12345') API.get(‘something’) .then(res => { expect(res.data) .toEqual(‘12345') }) })

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moving beyond tests #confoo 2020 @ruyadorno

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MICROSERVICES #confoo 2020 @ruyadorno

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#confoo 2020 @ruyadorno In the microservices world, folks are more used to mocking services

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#confoo 2020 @ruyadorno Given a typical microservices architecture…

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#confoo 2020 @ruyadorno Given a typical microservices architecture…

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#confoo 2020 @ruyadorno Given a typical microservices architecture… MOCK

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#confoo 2020 @ruyadorno Given a typical microservices architecture…

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#confoo 2020 @ruyadorno Given a typical microservices architecture…

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#confoo 2020 @ruyadorno Given a typical microservices architecture…

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#confoo 2020 @ruyadorno Given a typical microservices architecture…

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#confoo 2020 @ruyadorno Given a typical microservices architecture…

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#confoo 2020 @ruyadorno Given a typical microservices architecture… OR

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#confoo 2020 @ruyadorno Given a typical microservices architecture… OR

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#confoo 2020 @ruyadorno Given a typical microservices architecture… OR

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#confoo 2020 @ruyadorno now we know how to use mocks for tests

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#confoo 2020 @ruyadorno we’ve seen how they’re used in microservices for local development

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FRONT-END #confoo 2020 @ruyadorno

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#confoo 2020 @ruyadorno SUMMER 2017

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• Great library of reusable components • Good test setup with decent coverage • Awesome colleagues #confoo 2020 @ruyadorno

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#confoo 2020 @ruyadorno but

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• Microservices architecture • Impossible to run all services locally #confoo 2020 @ruyadorno

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#confoo 2020 @ruyadorno Staging environment: • Needs to be always online • Unstable, QA keeps breaking stuff • No easy way to easily change API responses

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#confoo 2020 @ruyadorno

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#confoo 2020 @ruyadorno

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#confoo 2020 @ruyadorno

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#confoo 2020 @ruyadorno

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#confoo 2020 @ruyadorno

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#confoo 2020 @ruyadorno let’s mock our way out

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#confoo 2020 @ruyadorno until you make it fake

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#confoo 2020 @ruyadorno The plan: • Mock all API responses using a static server • Bundle this mock server along with the front-end local dev environment

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#confoo 2020 @ruyadorno Mocked server •Allows for abstracting away the complexities of back-end envs •Lowers the barrier of joining the team

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#confoo 2020 @ruyadorno Mocked server •Allows for abstracting away the complexities of back-end envs •Lowers the barrier of joining the team

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#confoo 2020 @ruyadorno Mocked server •Allows for abstracting away the complexities of back-end envs •Lowers the barrier of joining the team •Makes it extra easy to change or tweak APIs

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#confoo 2020 @ruyadorno Trade-off, complexity is switched to maintaining these up-to-date mocks

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#confoo 2020 @ruyadorno

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#confoo 2020 @ruyadorno Where did we ended up?

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#confoo 2020 @ruyadorno •Development was much faster and predictable •Completely decoupled from back-end deliverables Pros

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#confoo 2020 @ruyadorno •Integration period was difficult •Maintaining the mocks updated could sometimes be very annoying Cons

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#confoo 2020 @ruyadorno It ended up influencing the way we work: • Smaller PRs, faster deliverables • More tests written

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#confoo 2020 @ruyadorno Hybrid system • Portable dev environment • Kept staging env around

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TOOLING #confoo 2020 @ruyadorno

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TOOLING #confoo 2020 @ruyadorno npm.im/create-react-app

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TOOLING #confoo 2020 @ruyadorno npm.im/create-react-app npm.im/webpack-dev-server

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TOOLING #confoo 2020 @ruyadorno npm.im/create-react-app npm.im/webpack-dev-server npm.im/npm-run-all

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TOOLING #confoo 2020 @ruyadorno

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TOOLING #confoo 2020 @ruyadorno

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TOOLING #confoo 2020 @ruyadorno npm.im/snapstub

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TOOLING #confoo 2020 @ruyadorno npm.im/snapstub

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TOOLING #confoo 2020 @ruyadorno npm.im/snapstub

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TOOLING #confoo 2020 @ruyadorno npm.im/snapstub

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TOOLING #confoo 2020 @ruyadorno npm.im/snapstub

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TOOLING #confoo 2020 @ruyadorno npm.im/snapstub

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TOOLING #confoo 2020 @ruyadorno npm.im/snapstub

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TOOLING #confoo 2020 @ruyadorno npm.im/snapstub

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TOOLING #confoo 2020 @ruyadorno npm.im/snapstub

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TOOLING #confoo 2020 @ruyadorno

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#confoo 2020 @ruyadorno all the things! mock

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Ruy Adorno Thanks! @ruyadorno ruyadorno.com

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#confoo 2020 @ruyadorno References • https://developer.mozilla.org/en-US/docs/Web/HTTP/Overview • https://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol • http://www.websiteoptimization.com/secrets/metrics/10-21-http-request.html • https://www.geeksforgeeks.org/tcp-3-way-handshake-process/ • https://martinfowler.com/articles/practical-test-pyramid.html • https://martinfowler.com/articles/mocksArentStubs.html • https://circleci.com/blog/how-to-test-software-part-i-mocking-stubbing-and-contract-testing/ • https://medium.com/@kapil.aggarwal1/api-mocks-and-why-should-we-care-418b24c35c25 • https://stoplight.io/blog/mock-api-test/ • https://openapi.tools/#mock • https://github.com/cdimascio/express-openapi-validator • https://graphql.org/blog/mocking-with-graphql/ • https://www.npmjs.com/package/jest • https://www.npmjs.com/package/jest-fetch-mock • https://www.npmjs.com/package/nock • https://www.npmjs.com/package/open-api-mocker • https://www.npmjs.com/package/create-react-app • https://www.npmjs.com/package/webpack-dev-server • https://www.npmjs.com/package/npm-run-all • https://www.npmjs.com/package/snapstub

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#confoo 2020 @ruyadorno Photo Credits • simple colored background: Photo by Andrej Lišakov on Unsplash • Vintage Document - Writing on Reverse: Photo by Andrew Buchanan on Unsplash • middle earth map: Photo by Liam Truong on Unsplash • Alphabet, letters, typography: Photo by Annie Spratt on Unsplash • brown wooden wall: Photo by karl on Unsplash • blank sketch book: Photo by Mike Tinnion on Unsplash • Coffee&Paper: Photo by Ivan Gromov on Unsplash • vintage letter: Photo by Mat Reding on Unsplash • Paper and Pencil with hand: Photo by Kelly Sikkema on Unsplash • Blank spiral notebook: Photo by Kelly Sikkema on Unsplash • When inspiration strikes: Photo by Tim Arterbury on Unsplash • Blank Paper and Pencil: Photo by Kelly Sikkema on Unsplash • Scattered white paper: Photo by Brandi Redd on Unsplash • simple coloured background: Photo by Andrej Lišakov on Unsplash • Typesetting in wood: Photo by Raphael Schaller on Unsplash • white block toy: Photo by Elodie Oudot on Unsplash • The Lost Art of Writing: Photo by Kelly Sikkema on Unsplash • yellow, black, green, and orange digital wallpaper: Photo by Hamed Daram on Unsplash • Minimal pencils on yellow: Photo by Joanna Kosinska on Unsplash • assorted-color paper and brown wooden pencil: Photo by Joanna Kosinska on Unsplash • Another photo from my visit to Czechowice-Dziedzice: Photo by Paweł Czerwiński on Unsplash • Feminine Paper Flat Lay: Photo by Kelly Sikkema on Unsplash • yellow painted wall: Photo by Janita Sumeiko on Unsplash • assorted-color coloring pencils: Photo by Plush Design Studio on Unsplash • pink metal board: Photo by Ryan Stone on Unsplash