I feel like this is such a simple […] toHaveTextContent ('My Name Is: C3P0') * To test a component that provides a context value, render a matching * consumer as the child import Enzyme from 'enzyme' import Adapter from 'enzyme-adapter-react-16' Enzyme.configure({ adapter: new Adapter() }) package.json "jest": { "setupFiles": [ "test/setup.js" ] } This configures Enzyme for React v16, and Jest to automatically configure Enzyme for you. getByText (/^My Name Is:/)). Using Enzyme with Mocha. getByTestId ('location-display')). Jest expect has a chainable .not assertion which negates any following assertion. Using Enzyme with Karma. jest-enzyme with Jest. No testing solution out there is perfect. This is seen as good practice at the unit test level, as we don’t want these tests dependant on an external API which will … Between test runs we need mocked/spied on imports and functions to be reset so that assertions don’t fail due to stale calls (from a … expect (screen. Pastebin.com is the number one paste tool since 2002. Jest is the best option for most React Native projects. Example: const mathjs = require ( 'mathjs' ) test ( `The mathjs log function` , () => { const spy = jest . Also all TypeScript files should be in a src folder which is always recommended (even without Jest… This is true for stub/spy assertions like .toBeCalled(), .toHaveBeenCalled(). Using Enzyme with Browserify. In cases 2 and 3, we use queryByTestId instead of getByTestId.queryByTestId doesn't fail when the queried element doesn't exist, instead, it returns either a value or null and that's what we test with expect().toBeTruthy() and expect().toBeNull(). spyOn ( mathjs , 'log' ) const result = mathjs . That said, jest is an excellent unit testing option which provides great TypeScript support. toHaveTextContent (route) Reducing boilerplate # You can use the wrapper option to wrap a MemoryRouter around the component you want to … Using Enzyme with SystemJS. Pastebin is a website where you can store text online for a set period of time. Jest documentation There are other adapters in Enzyme’s installation instructions. With Jasmine this is super easy — The application code: And the test code: What’s the equivalent with Jest? This won’t be a deep dive into unit testing React components but I will present some options for mocking external services. jest.requireActual(moduleName) Returns the actual module instead of a mock, bypassing all checks on whether the module should receive a mock implementation or not. It’s possible to require/import and expose the real module while using jest.mock. The Question : 316 people think this question is useful I want to test that one of my ES6 modules calls another ES6 module in a particular way. Jest is built into React, which makes Jest a simple, out-of-the-box solution to for React Native unit testing. expect (screen. Using Enzyme with Webpack. should-enzyme for should.js. 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