How to use getRecordEntries method in Jest

OK I got it. Here is how I fixed it! I ended up doing without any mocking libraries for axios!

Create a mock for axios in src/__mocks__:

// src/__mocks__/axios.ts

const mockAxios = jest.genMockFromModule('axios')

// this is the key to fix the axios.create() undefined error!
mockAxios.create = jest.fn(() => mockAxios)

export default mockAxios

Then in your test file, the gist would look like:

import mockAxios from 'axios'
import configureMockStore from 'redux-mock-store'
import thunk from 'redux-thunk'

// for some reason i need this to fix reducer keys undefined errors..
jest.mock('../../store/rootStore.ts')

// you need the 'async'!
test('Retrieve transaction data based on a date range', async () => {
  const middlewares = [thunk]
  const mockStore = configureMockStore(middlewares)
  const store = mockStore()

  const mockData = {
    'data': 123
  }

  /** 
   *  SETUP
   *  This is where you override the 'post' method of your mocked axios and return
   *  mocked data in an appropriate data structure-- {data: YOUR_DATA} -- which
   *  mirrors the actual API call, in this case, the 'reportGet'
   */
  mockAxios.post.mockImplementationOnce(() =>
    Promise.resolve({ data: mockData }),
  )

  const expectedActions = [
    { type: REQUEST_TRANSACTION_DATA },
    { type: RECEIVE_TRANSACTION_DATA, data: mockData },
  ]

  // work
  await store.dispatch(reportGet())

  // assertions / expects
  expect(store.getActions()).toEqual(expectedActions)
  expect(mockAxios.post).toHaveBeenCalledTimes(1)
})

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.

We excluded the karma types in the tsconfig and added jest types. The IDE now doesn't pick the karma types but it works for us since most of our tests are now in jest and very few left in karma and build process works now correctly since there are no more type conflicts.

The mock constructor provided by Jest only records this as the instance so if your mock constructor returns a different object then that object won't be recorded in the instances array.

To get the behavior you are wanting just mock with a standard function and use this:

__mocks__/ssh2-sftp-client.ts

const mockSsh2SftpClient = jest.fn(function() {
  this.connect = jest.fn();
  this.end = jest.fn();
  this.on = jest.fn();
});

export default mockSsh2SftpClient

toBeInTheDocument is not part of RTL. You need to install jest-dom to enable it.

And then import it in your test files by:

import '@testing-library/jest-dom'

From looking at the docs, and my own experimentation to confirm it, the difference is in the handling of objects nested within the props passed as an expectation.

If the expectation object has a property, containing an object, which contains some but not all of the properties in the equivalent property of the actual object, then:

• .toMatchObject() will still pass, as seen in the docs.

• expect.objectContaining() will fail (unless you declare that property in the expectation object itself with expect.objectContaining())

Examples (tested in Jest):

  // objectContaining, with nested object, containing full props/values
  // PASSES
  expect({ position: { x: 0, y: 0 } }).toEqual(expect.objectContaining({
    position: {
      x: expect.any(Number),
      y: expect.any(Number)
    }
  }));

  // objectContaining, with nested object, containing partial props/values
  // FAILS
  expect({ position: { x: 0, y: 0 } }).toEqual(expect.objectContaining({
    position: {
      x: expect.any(Number)
    }
  }));

  // objectContaining, with nested object, also declared with objectContaining, containing partial props/values
  // PASSES
  expect({ position: { x: 0, y: 0 } }).toEqual(expect.objectContaining({
    position: expect.objectContaining({
      x: expect.any(Number)
    })
  }));

  // toMatchObject, with nested object, containing full props/values
  // PASSES
  expect({ position: { x: 0, y: 0 } }).toMatchObject({
    position: {
      x: expect.any(Number),
      y: expect.any(Number)
    }
  });

  // toMatchObject, with nested object, containing partial props/values
  // PASSES
  expect({ position: { x: 0, y: 0 } }).toMatchObject({
    position: {
      x: expect.any(Number)
    }
  });

From the docs for setupFilesAfterEnv:

setupFiles executes before the test framework is installed in the environment

(That information should probably be added to the setupFiles section of the docs as well.)

setupFiles runs before the test framework is installed. I'm a bit surprised that jest.setTimeout is defined within a setup file. In any case, calling jest.setTimeout doesn't work right from within a file in setupFiles.

Instead, use setupFilesAfterEnv which runs

immediately after the test framework has been installed in the environment

Note that setupFilesAfterEnv was introduced in version 24.0.0.

If you are using an earlier version of Jest use the older setupTestFrameworkScriptFile instead.

Module mocks are hoisted when possible with babel-jest transform, so this will result in mocked module:

import ModuleA from "../src/ModuleA"
jest.mock("../src/ModuleA") // hoisted to be evaluated prior to import

This won't work if a module should be mocked per test basis, because jest.mock resides in beforeEach function.

In this case require should be used:

describe("ModuleA", () => {
    beforeEach(() => {
        jest.mock("../src/ModuleA")
    })

    it("should return the mock name", () => {
        const ModuleA = require("../src/ModuleA").default;
        const name = ModuleA.getModuleName()
        expect(name).toBe("mockModuleA")
    })
})

Since it's not an export but a method in default export that should be mocked, this can also be achieved by mocking ModuleA.getModuleName instead of entire module.