How to use extractData method in Jest

Looking at the jest doc (https://facebook.github.io/jest/docs/en/expect.html#expectobjectcontainingobject). It seems you can do something like this:

 expect(api.submitForm).toBeCalledWith(
    expect.objectContaining({
     foo : 'foo',
      bar: 'bar'
    }),
  );

Maybe you want to make a module that can know what file required it, you can use module.parent. It is the module that first required this one. And then you can use path.dirname to get the directory of the file.

So index.js should be like this

const path = require('path')

const readRootConfig = function() {
  const dir = path.dirname(module.parent.filename)
  console.log(dir); // show the working dir
  const config = require(`${dir}/config.js`);
}

I think you need to add RNShare.xcodeproj to your Project' Libraries and then go to General->Linked Frameworks and Libraries, add libRNShare.a. It's fixed my problem.

Your output says that testMatch had 1 match, which may be your __tests__/index.test.js file. It seems that your testPathIgnorePatterns is causing that test suite to be ignored. No tests found In /usr/src/app says that Jest is looking for tests in /usr/src/app, and testPathIgnorePatterns: /node_modules/,/src,src says that Jest is ignoring files in /src directories.

Either point Jest to look at the location of your __tests__/index.test.js file if it is outside the /src directory, or stop testPathIgnorePatterns from ignoring the /src directory.

You could take advantage of the second parameter of jest.mock(), which would let you specify a custom implementation of the mocked module to use in testing.

Inside this custom implementation, you can also define some convenience helpers to emulate expected implementation values (e.g. weekday()).

// send-module.test.js

jest.mock('moment-timezone', () => {
    let weekday
    const moment = jest.fn(() => {
        return {
            weekday: jest.fn(() => weekday),
        }
    })
    moment.tz = {
        setDefault: jest.fn(),
    }
    // Helper for tests to set expected weekday value
    moment.__setWeekday = (value) => weekday = value
    return moment;
})

const sendModule = require('./send-module')

test('test', () => {
    require('moment-timezone').__setWeekday(3)
    expect(sendModule.send()).toBe(3)
})

Do note that manually providing the mock per test file can get tedious and repetitive if the module being mocked has a huge API surface. To address the latter case, you can consider authoring some manual mocks to make them reusable (i.e. using the __mocks__ directory convention) and supplement that by using jest.genMockFromModule().

The Jest documentation has some guidance about this.

Jest will terminate after one assertion fails. This is to support the idea that a test should assert exactly one thing. It's not necessarily bad to have multiple related assertions in a single test, but if your unit test tests a single piece of functionality and one assertion fails, it doesn't really matter if the others are correct or not. If you need to figure out what's wrong with your test result, just debug or console.log concreteScopes.

I think what you need is to check the rejected error

const foo = require('./foo');
describe('foo', () => {
  it('should log and rethrow', async () => {
    await expect(foo()).rejects.toEqual('error');
  });
});

As of react-scripts 2.10 you can add TypeScript to an existing project or when creating a new project.

existing project

yarn add typescript @types/node @types/react @types/react-dom @types/jest --dev

...then rename your .js files to .tsx

new project

yarn create react-app my-app --template typescript

You can read more in the docs.

If you are having trouble, the following from the troubleshooting section of the docs might help:

Troubleshooting

If your project is not created with TypeScript enabled, npx may be using a cached version of create-react-app. Remove previously installed versions with npm uninstall -g create-react-app or yarn global remove create-react-app (see #6119).

You could try to assign the localVue variable as a global variable in your setupFiles. This would allow you access localVue variable in every test, like so:

import { createLocalVue } from '@vue/test-utils'
import BootstrapVue from 'bootstrap-vue'

global.localVue = createLocalVue()

global.localVue.use(BootstrapVue)

Then use it like this in your test:

const localVue = global.localVue

const wrapper = shallowMount(MyComponent, {
  localVue,
  propsData: { value: 'someVal' }
})