jestjs

问题 Let's say I have a class like following: class SomeClass { constructor(a, b) { this.a = a; this.b = b; } } How can I test through Jest that constructor was initialized the right way? Say... this.a = a and this.b = b and not vice versa? I know that I can execute toBeCalledWith but that won't let me check the constructor's logic. I was also thinking about making mockImplementation but in this case it seems pointless as I will rewrite the logic, or I may not be aware of all the nuances of

问题 I'm trying to install Mocha and Jest with types on one project. We use strict typecheck, so I get errors related to conflicting globals type. I've tried to create ambiguous module declaration, defining only Mocha in types at tsconfig . I've been trying to remove Jest's declaration - but that would partially help. Disabling strict typecheck or lib check is not an option. I expected to work it properly, but instead got the next errors. node_modules/@types/jest/index.d.ts(29,13): error TS2403:

问题 I'm trying to install Mocha and Jest with types on one project. We use strict typecheck, so I get errors related to conflicting globals type. I've tried to create ambiguous module declaration, defining only Mocha in types at tsconfig . I've been trying to remove Jest's declaration - but that would partially help. Disabling strict typecheck or lib check is not an option. I expected to work it properly, but instead got the next errors. node_modules/@types/jest/index.d.ts(29,13): error TS2403:

问题 I have handlers for unhandledRejection s and uncaughtException s: bin.js ['unhandledRejection', 'uncaughtException'].forEach(event => { process.on(event, err => logger.error(err)); }); Now I want to test them with jest : bin.test.js const bin = require('../bin'); test('catches unhandled rejections', async () => { const error = new Error('mock error'); await Promise.reject(error); expect(logger.error).toHaveBeenCalledWith(error); }); test('catches uncaught exceptions', () => { const error =

问题 I am writing tests using Jest for components that use canvas elements. I keep getting an error when I run my tests that looks like this. Error: Not implemented: HTMLCanvasElement.prototype.getContext (without installing the canvas npm package) From my understanding Jest uses jsdom for its testing and that jsdom is compatible with canvas if you install the canvas or canvas-prebuilt packages. I have tried installing each of these packages and neither of them have resolved the error. The only

问题 I am writing tests using Jest for components that use canvas elements. I keep getting an error when I run my tests that looks like this. Error: Not implemented: HTMLCanvasElement.prototype.getContext (without installing the canvas npm package) From my understanding Jest uses jsdom for its testing and that jsdom is compatible with canvas if you install the canvas or canvas-prebuilt packages. I have tried installing each of these packages and neither of them have resolved the error. The only

问题 I'm using react-testing-library within a project of mine and am trying to write tests that validate in-app routing. e.g. testing that a button on the AccessDenied page brings you back to the Home page. I've been able to write these sorts of tests successfully for my App component because it defines all of the app routes. But if AccessDenied is one of those routes , how do I need to set up my tests to validate a button clicked there will route my back to Home? Here is a contrived example: App

问题 I'm using react-testing-library within a project of mine and am trying to write tests that validate in-app routing. e.g. testing that a button on the AccessDenied page brings you back to the Home page. I've been able to write these sorts of tests successfully for my App component because it defines all of the app routes. But if AccessDenied is one of those routes , how do I need to set up my tests to validate a button clicked there will route my back to Home? Here is a contrived example: App

问题 When writing a unit test in Jest, how can I test that an array contains exactly the expected values in any order ? In Chai , I can write: const value = [1, 2, 3]; expect(value).to.have.members([2, 1, 3]); What's the equivalent syntax in Jest? 回答1: Another way is to use the custom matcher .toIncludeSameMembers() from jest-community/jest-extended. Example given from the README test('passes when arrays match in a different order', () => { expect([1, 2, 3]).toIncludeSameMembers([3, 1, 2]); expect

问题 When writing a unit test in Jest, how can I test that an array contains exactly the expected values in any order ? In Chai , I can write: const value = [1, 2, 3]; expect(value).to.have.members([2, 1, 3]); What's the equivalent syntax in Jest? 回答1: Another way is to use the custom matcher .toIncludeSameMembers() from jest-community/jest-extended. Example given from the README test('passes when arrays match in a different order', () => { expect([1, 2, 3]).toIncludeSameMembers([3, 1, 2]); expect