Jest doesn’t support ES6 module and hence throwing this error when you directly run the test with Jest. if you want to run like that then you have to add babel. On the other side, when you run the test with react-scripts it uses babel behind the scene to Transpile the code. In newer version … Read more
I’ve started employing the import * as obj style within my tests, which imports all exports from a module as properties of an object which can then be mocked. I find this to be a lot cleaner than using something like rewire or proxyquire or any similar technique. I can’t speak for traceur which was … Read more
If none of the other solutions worked for you, you can try this in your jest “moduleNameMapper”: { “^lodash-es$”: “lodash” } It will replace lodash-es with the commonjs version during testing runtime.
Even though I have tried them separately, I haven’t tried them together (transform and transformIgnorePatterns). So this jest configuration solved my issue: “jest”: { “preset”: “ts-jest”, “testEnvironment”: “node”, “transform”: { “node_modules/variables/.+\\.(j|t)sx?$”: “ts-jest” }, “transformIgnorePatterns”: [ “node_modules/(?!variables/.*)” ] }, My mistakes were: Not using transform and transformIgnorePatterns together. And defining babel-jest as the transformer instead of … Read more
moduleNameMapper is the setting that tells Jest how to interpret files with different extension. You need to tell it how to handle Less files. Create a file like this in your project (you can use a different name or path if you’d like): config/CSSStub.js module.exports = {}; This stub is the module we will tell … Read more
You have to use global to access objects in the global context global.console = {warn: jest.fn()} expect(console.warn).toBeCalled() or use jest.spyOn added in 19.0.0 jest.spyOn(global.console, ‘warn’)
This means, that a file is not transformed through TypeScript compiler, e.g. because it is a JS file with TS syntax, or it is published to npm as uncompiled source files. Here’s what you can do. Adjust your transformIgnorePatterns allowed list: { “jest”: { “transformIgnorePatterns”: [ “node_modules/(?!@ngrx|(?!deck.gl)|ng-dynamic)” ] } } By default Jest doesn’t transform … Read more
Jest suppresses the console log message by default. In order to show the console log message, set silent option to false at the command line set –silent=false in the command line: npm run test — –silent=false
From the command line, use the –testNamePattern or -t flag: jest -t ‘fix-order-test’ This will only run tests that match the test name pattern you provide. It’s in the Jest documentation. Another way is to run tests in watch mode, jest –watch, and then press P to filter the tests by typing the test file … Read more
I would recommend an entirely different way of approaching this. Rather than trying to mock Axios, which is a relatively complicated API that you don’t own, test at the network boundary using a tool like msw. This allows you to freely refactor the implementation without needing to change the tests, giving you more confidence it’s … Read more