I have a quite simple test, basically I'm trying to mock i18next's t function:
import { t } from 'i18next';
import { changeDocumentTitle } from './utils';
jest.mock('i18next');
const tMock = (key: string): string => key;
beforeAll(() => {
(t as jest.Mock).mockImplementation(tMock);
});
test('test changeDocumentTitle function', () => {
changeDocumentTitle('string');
expect(document.title).toEqual(tMock('string'));
});
and the changeDocumentTitle implementation:
import { t } from 'i18next';
export const changeDocumentTitle = (titleKey: string): void => {
document.title = t(`${titleKey}`);
};
Unfortunately, the test fails. But if I change it from beforeAll to beforeEach, everything's fine. How is that? Why beforeAll is not applying my mock unlike beforeEach?
Thanks in advance.
Since react-scripts v4 it added the default jest config resetMocks: true: https://github.com/facebook/create-react-app/releases/tag/v4.0.0
This means that the mocks are being reset before the tests runs with beforeAll. I recommended keeping resetMocks: true, because tests should be isolated.
I have a subscriber that dispatches an action based on the parameters supplied to a pub event
// subscriptions.js
import store from '../store';
import { action } from '../actions';
export const subscribeToToggle = () => {
window.$.subscribe('action/toggle', (_e, isToggleOn) => {
if (isToggleOn=== true){
store.dispatch(action());
}
});
};
In my test file I write 2 tests that test that the action is sent only when true is supplied.
// subscriptions.test.js
import { subscribeToToggle } from './subscriptions';
import jQuery from 'jquery';
import { actionTypes } from '../constants';
import store from '../store';
jest.mock('../store');
beforeEach(() => {
window.$ = jQuery;
window.$.unsubscribe('action/toggle');
});
test('Action not sent when false', () => {
subscribeToToggleOpen();
window.$.publish('action/toggle', false);
expect(store.getActions().length).toBe(0);
});
test('Action sent when true', () => {
subscribeToToggleOpen();
window.$.publish('action/toggle', true);
expect(store.getActions().length).toBe(1);
expect(store.getActions()[0].type).toBe(actionTypes.ACTION);
});
I have the following mocked store using redux-test-utils
import { createMockStore } from 'redux-test-utils';
let store = null;
store = createMockStore('');
export default store;
The issue I face is that my test only pass when the false test comes first. If they are the other way around the 'Action not sent when false' test fails as it sees the action supplied by the 'Action sent when true' test.
Is there any way for me to use the beforeEach method to reset the mocked store object?
In this case, the problem is that your store is essentially a singleton. This can create issues when you are trying to do things like this and is generally kind of an anti-pattern.
Instead of exporting a store object, it'd probably be better if you exported a getStore() function which could be called to get the store. In that case, you could then do:
getStore().dispatch(action());
Inside of that, you could then have other helper functions to be able to replace the store that is being returned by it. That file could look something like this:
import { createMockStore } from 'redux-test-utils';
let store = createMockStore('');
export default () => store;
Then, inside of there, you can add another which could be resetStore as a non-default export:
export const resetStore = () => store = createMockStore('');
It would still technically be a singleton, but it's now a singleton you can have some control over.
Then, in your beforeEach() in your tests, just call resetStore():
import { resetStore } from '../store';
beforeEach(() => {
resetStore();
});
This would also require you to update your real code to use getStore() instead of store directly, but it'll probably be a beneficial change in the long run.
Complete Updated Version:
// subscriptions.js
import getStore from '../store';
import { action } from '../actions';
export const subscribeToToggle = () => {
window.$.subscribe('action/toggle', (_e, isToggleOn) => {
if (isToggleOn=== true){
getStore().dispatch(action());
}
});
};
// subscriptions.test.js
import { subscribeToToggle } from './subscriptions';
import jQuery from 'jquery';
import { actionTypes } from '../constants';
import getStore, { resetStore } from '../store';
jest.mock('../store');
beforeEach(() => {
window.$ = jQuery;
window.$.unsubscribe('action/toggle');
resetStore();
});
test('Action not sent when false', () => {
subscribeToToggleOpen();
window.$.publish('action/toggle', false);
expect(getStore().getActions().length).toBe(0);
});
test('Action sent when true', () => {
subscribeToToggleOpen();
window.$.publish('action/toggle', true);
expect(getStore().getActions().length).toBe(1);
expect(getStore().getActions()[0].type).toBe(actionTypes.ACTION);
});
import { createMockStore } from 'redux-test-utils';
let store;
export const resetStore = () => { store = createMockStore(''); }
resetStore(); // init the store, call function to keep DRY
export default () => store;
Beyond that, the other way would be to have a global reducer which could reset the state of the store to it's default, but that would be messier and I don't really think would generally fit with writing a unit test.
The Problem:
I have a simple React component I'm using to learn to test components with Jest and Enzyme. As I'm working with props, I added the prop-types module to check for properties in development. prop-types uses console.error to alert when mandatory props are not passed or when props are the wrong data type.
I wanted to mock console.error to count the number of times it was called by prop-types as I passed in missing/mis-typed props.
Using this simplified example component and test, I'd expect the two tests to behave as such:
The first test with 0/2 required props should catch the mock calling twice.
The second test with 1/2 required props should catch the mock called once.
Instead, I get this:
The first test runs successfully.
The second test fails, complaining that the mock function was called zero times.
If I swap the order of the tests, the first works and the second fails.
If I split each test into an individual file, both work.
console.error output is suppressed, so it's clear it's mocked for both.
I'm sure I am missing something obvious, like clearing the mock wrong or whatever.
When I use the same structure against a module that exports a function, calling console.error some arbitrary number of times, things work.
It's when I test with enzyme/react that I hit this wall after the first test.
Sample App.js:
import React, { Component } from 'react';
import PropTypes from 'prop-types';
export default class App extends Component {
render(){
return(
<div>Hello world.</div>
);
}
};
App.propTypes = {
id : PropTypes.string.isRequired,
data : PropTypes.object.isRequired
};
Sample App.test.js
import React from 'react';
import { mount } from 'enzyme';
import App from './App';
console.error = jest.fn();
beforeEach(() => {
console.error.mockClear();
});
it('component logs two errors when no props are passed', () => {
const wrapper = mount(<App />);
expect(console.error).toHaveBeenCalledTimes(2);
});
it('component logs one error when only id is passed', () => {
const wrapper = mount(<App id="stringofstuff"/>);
expect(console.error).toHaveBeenCalledTimes(1);
});
Final note: Yeah, it's better to write the component to generate some user friendly output when props are missing, then test for that. But once I found this behavior, I wanted to figure out what I'm doing wrong as a way to improve my understanding. Clearly, I'm missing something.
I ran into a similar problem, just needed to cache the original method
const original = console.error
beforeEach(() => {
console.error = jest.fn()
console.error('you cant see me')
})
afterEach(() => {
console.error('you cant see me')
console.error = original
console.error('now you can')
})
Given the behavior explained by #DLyman, you could do it like that:
describe('desc', () => {
beforeAll(() => {
jest.spyOn(console, 'error').mockImplementation(() => {});
});
afterAll(() => {
console.error.mockRestore();
});
afterEach(() => {
console.error.mockClear();
});
it('x', () => {
// [...]
});
it('y', () => {
// [...]
});
it('throws [...]', () => {
shallow(<App />);
expect(console.error).toHaveBeenCalled();
expect(console.error.mock.calls[0][0]).toContain('The prop `id` is marked as required');
});
});
What guys wrote above is correct. I've encoutered similar problem and here's my solution. It takes also into consideration situation when you're doing some assertion on the mocked object:
beforeAll(() => {
// Create a spy on console (console.log in this case) and provide some mocked implementation
// In mocking global objects it's usually better than simple `jest.fn()`
// because you can `unmock` it in clean way doing `mockRestore`
jest.spyOn(console, 'log').mockImplementation(() => {});
});
afterAll(() => {
// Restore mock after all tests are done, so it won't affect other test suites
console.log.mockRestore();
});
afterEach(() => {
// Clear mock (all calls etc) after each test.
// It's needed when you're using console somewhere in the tests so you have clean mock each time
console.log.mockClear();
});
You didn't miss anything. There is a known issue (https://github.com/facebook/react/issues/7047) about missing error/warning messages.
If you switch your test cases ('...when only id is passed' - the fisrt, '...when no props are passed' - the second) and add such
console.log('mockedError', console.error.mock.calls); inside your test cases, you can see, that the message about missing id isn't triggered in the second test.
For my solutions I'm just wrapping original console and combine all messages into arrays. May be someone it will be needed.
const mockedMethods = ['log', 'warn', 'error']
export const { originalConsoleFuncs, consoleMessages } = mockedMethods.reduce(
(acc: any, method: any) => {
acc.originalConsoleFuncs[method] = console[method].bind(console)
acc.consoleMessages[method] = []
return acc
},
{
consoleMessages: {},
originalConsoleFuncs: {}
}
)
export const clearConsole = () =>
mockedMethods.forEach(method => {
consoleMessages[method] = []
})
export const mockConsole = (callOriginals?: boolean) => {
const createMockConsoleFunc = (method: any) => {
console[method] = (...args: any[]) => {
consoleMessages[method].push(args)
if (callOriginals) return originalConsoleFuncs[method](...args)
}
}
const deleteMockConsoleFunc = (method: any) => {
console[method] = originalConsoleFuncs[method]
consoleMessages[method] = []
}
beforeEach(() => {
mockedMethods.forEach((method: any) => {
createMockConsoleFunc(method)
})
})
afterEach(() => {
mockedMethods.forEach((method: any) => {
deleteMockConsoleFunc(method)
})
})
}
I have the following component script (some irrelevant bits removed):
import api from '#/lib/api';
export default {
methods: {
upload (formData) {
api.uploadFile(formData).then(response => {
this.$emit('input', response.data);
});
}
}
};
And I have the following test, which uses avoriaz to mount the Vue instance:
import { mount } from 'avoriaz';
import { expect } from 'chai';
import sinon from 'sinon';
import UploadForm from '#/components/UploadForm';
describe('upload', () => {
it('passes form data to api.uploadFile', () => {
const testFormData = { test: 'test' };
const api = {
uploadFile: sinon.spy()
};
const wrapper = mount(UploadForm);
wrapper.vm.api = api;
wrapper.vm.upload(testFormData);
expect(api.uploadFile.called).to.equal(true);
});
});
My sinon spy is never called, and I've tried a couple different variations on the above. What is the best way to spy on an imported function like this? Or am I conceptually approaching this the wrong way?
Problem
You need to stub the api dependency, which is a dependency of the file. This can't be done through the vue instance, since api is not a part of the vue component.
You need to stub the file dependency.
Solution
One method to do this is to use inject-loader.
Steps
Install inject-loader
npm install --save-dev inject-loader
At the top of your file, import UploadForm with inject-loader and vue-loader:
import UploadFormFactory from '!!vue-loader?inject!#/components/UploadForm';
This is a factory function that returns UploadForm with dependencies stubbed.
Now, in your test you need to call UploadFormFactory with the dependency you want stubbed:
const api = {
uploadFile: sinon.spy()
};
const UploadForm = UploadFormFactory({
'#/lib/api': api
})
So your test file will look like:
import { mount } from 'avoriaz';
import { expect } from 'chai';
import sinon from 'sinon';
import UploadFormFactory from '!!vue-loader?inject!#/components/UploadForm';
describe('upload', () => {
it('passes form data to api.uploadFile', () => {
const api = {
uploadFile: sinon.spy()
};
const UploadForm = UploadFormFactory({
'#/lib/api': api
})
const testFormData = { test: 'test' };
const api = {
uploadFile: sinon.spy()
};
const wrapper = mount(UploadForm);
wrapper.vm.upload(testFormData);
expect(api.uploadFile.called).to.equal(true);
});
});
More info
I've written a tutorial with more detail here - https://www.coding123.org/stub-dependencies-vue-unit-tests/
I think Edd's answer is the most encompassing for most scenarios, so I'm marking his as the accepted answer. However, the workaround I came up with was to make the api library a global service (Vue.prototype.$api = api) in my main.js file, and then overwrite the global with a stub before each test.
describe('UploadForm.vue', () => {
let wrapper;
const uploadFile = sinon.stub().returns(Promise.resolve({ data: 0 }));
beforeEach(() => {
wrapper = mount(UploadForm, {
globals: {
$api: { uploadFile }
}
});
});
// ...
I have a file that relies on an exported const variable. This variable is set to true but if ever needed can be set to false manually to prevent some behavior if downstream services request it.
I am not sure how to mock a const variable in Jest so that I can change it's value for testing the true and false conditions.
Example:
//constants module
export const ENABLED = true;
//allowThrough module
import { ENABLED } from './constants';
export function allowThrough(data) {
return (data && ENABLED === true)
}
// jest test
import { allowThrough } from './allowThrough';
import { ENABLED } from './constants';
describe('allowThrough', () => {
test('success', () => {
expect(ENABLED).toBE(true);
expect(allowThrough({value: 1})).toBe(true);
});
test('fail, ENABLED === false', () => {
//how do I override the value of ENABLED here?
expect(ENABLED).toBe(false) // won't work because enabled is a const
expect(allowThrough({value: 1})).toBe(true); //fails because ENABLED is still true
});
});
This example will work if you compile ES6 modules syntax into ES5, because in the end, all module exports belong to the same object, which can be modified.
import { allowThrough } from './allowThrough';
import { ENABLED } from './constants';
import * as constants from './constants';
describe('allowThrough', () => {
test('success', () => {
constants.ENABLED = true;
expect(ENABLED).toBe(true);
expect(allowThrough({ value: 1 })).toBe(true);
});
test('fail, ENABLED === false', () => {
constants.ENABLED = false;
expect(ENABLED).toBe(false);
expect(allowThrough({ value: 1 })).toBe(false);
});
});
Alternatively, you can switch to raw commonjs require function, and do it like this with the help of jest.mock(...):
const mockTrue = { ENABLED: true };
const mockFalse = { ENABLED: false };
describe('allowThrough', () => {
beforeEach(() => {
jest.resetModules();
});
test('success', () => {
jest.mock('./constants', () => mockTrue)
const { ENABLED } = require('./constants');
const { allowThrough } = require('./allowThrough');
expect(ENABLED).toBe(true);
expect(allowThrough({ value: 1 })).toBe(true);
});
test('fail, ENABLED === false', () => {
jest.mock('./constants', () => mockFalse)
const { ENABLED } = require('./constants');
const { allowThrough } = require('./allowThrough');
expect(ENABLED).toBe(false);
expect(allowThrough({ value: 1 })).toBe(false);
});
});
Unfortunately none of the posted solutions worked for me or to be more precise some did work but threw linting, TypeScript or compilation errors, so I will post my solution that both works for me and is compliant with current coding standards:
// constants.ts
// configuration file with defined constant(s)
export const someConstantValue = true;
// module.ts
// this module uses the defined constants
import { someConstantValue } from './constants';
export const someCheck = () => someConstantValue ? 'true' : 'false';
// module.test.ts
// this is the test file for module.ts
import { someCheck } from './module';
// Jest specifies that the variable must start with `mock`
const mockSomeConstantValueGetter = jest.fn();
jest.mock('./constants', () => ({
get someConstantValue() {
return mockSomeConstantValueGetter();
},
}));
describe('someCheck', () => {
it('returns "true" if someConstantValue is true', () => {
mockSomeConstantValueGetter.mockReturnValue(true);
expect(someCheck()).toEqual('true');
});
it('returns "false" if someConstantValue is false', () => {
mockSomeConstantValueGetter.mockReturnValue(false);
expect(someCheck()).toEqual('false');
});
});
There is another way to do it in ES6+ and jest 22.1.0+ thanks to getters and spyOn.
By default, you cannot spy on primitive types like boolean or number. You can though replace an imported file with your own mock. A getter method still acts like a primitive member but allows us to spy on it. Having a spy on our target member you can basically do with it whatever you want, just like with a jest.fn() mock.
Below an example
// foo.js
export const foo = true; // could be expression as well
// subject.js
import { foo } from './foo'
export default () => foo
// subject.spec.js
import subject from './subject'
jest.mock('./foo', () => ({
get foo () {
return true // set some default value
}
}))
describe('subject', () => {
const mySpy = jest.spyOn(subject.default, 'foo', 'get')
it('foo returns true', () => {
expect(subject.foo).toBe(true)
})
it('foo returns false', () => {
mySpy.mockReturnValueOnce(false)
expect(subject.foo).toBe(false)
})
})
Read more in the docs.
Thanks to #Luke I was able to expand on his answer for my needs. I had the requirements of:
Only mocking certain values in the file - not all
Running the mock only inside a single test.
Turns out that doMock() is like mock() but doesn't get hoisted. In addition requireActual() can be used to grab original data.
My config.js file - I need to mock only part of it
export const SOMETHING = 'blah'
export const OTHER = 'meh'
My test file
// import { someFunc } from 'some/file' // This won't work with doMock - see below
describe('My test', () => {
test('someFunc() does stuff', async () => {
// Here I mock the config file which gets imported somewhere deep in my code
jest.doMock('config.js', () => {
// Grab original
const originalModule = jest.requireActual('config')
// Return original but override some values
return {
__esModule: true, // Depends on your setup
...originalModule,
SOMETHING: 'boom!'
}
})
// Because `doMock` doesn't get hoisted we need to import the function after
const { someFunc } = await import(
'some/file'
)
// Now someFunc will use the original config values but overridden with SOMETHING=boom!
const res = await someFunc()
})
})
Depending on other tests you may also need to use resetModules() somewhere such as beforeAll or afterAll.
Docs:
doMock
requireActual
resetModules
Since we can't override/mock the value directly. we can use the below hack
// foo.js
export const foo = true; // could be expression as well
// spec file
import * as constants from './foo'
Object.defineProperty(constant, 'foo', {value: 1})
For functions:
Object.defineProperty(store, 'doOneThing', {value: jest.fn()})
For me the simplest solution was to redefine the imported object property, as decribed here:
https://flutterq.com/how-to-mock-an-exported-const-in-jest/
// foo.js
export const foo = true; // could be expression as well
// spec file
import * as constants from './foo'
Object.defineProperty(constant, 'foo', {value: 1, writable: true})
Facing the same issue, I found this blog post very useful, and much simpler than #cyberwombat use case :
https://remarkablemark.org/blog/2018/06/28/jest-mock-default-named-export/
// esModule.js
export default 'defaultExport';
export const namedExport = () => {};
// esModule.test.js
jest.mock('./esModule', () => ({
__esModule: true, // this property makes it work
default: 'mockedDefaultExport',
namedExport: jest.fn(),
}));
import defaultExport, { namedExport } from './esModule';
defaultExport; // 'mockedDefaultExport'
namedExport; // mock function
The most common scenario I needed was to mock a constant used by a class (in my case, a React component but it could be any ES6 class really).
#Luke's answer worked great for this, it just took a minute to wrap my head around it so I thought I'd rephrase it into a more explicit example.
The key is that your constants need to be in a separate file that you import, so that this import itself can be stubbed/mocked by jest.
The following worked perfectly for me.
First, define your constants:
// src/my-component/constants.js
const MY_CONSTANT = 100;
export { MY_CONSTANT };
Next, we have the class that actually uses the constants:
// src/my-component/index.jsx
import { MY_CONSTANT } from './constants';
// This could be any class (e.g. a React component)
class MyComponent {
constructor() {
// Use the constant inside this class
this.secret = MY_CONSTANT;
console.log(`Current value is ${this.secret}`);
}
}
export default MyComponent
Lastly, we have the tests. There's 2 use cases we want to handle here:
Mock the generate value of MY_CONSTANT for all tests inside this file
Allow the ability for a specific test to further override the value of MY_CONSTANT for that single test
The first part is acheived by using jest.mock at the top of your test file.
The second is acheived by using jest.spyOn to further spy on the exported list of constants. It's almost like a mock on top of a mock.
// test/components/my-component/index.js
import MyComponent from 'src/my-component';
import allConstants from 'src/my-component/constants';
jest.mock('src/my-component/constants', () => ({
get MY_CONSTANT () {
return 30;
}
}));
it('mocks the value of MY_CONSTANT', () => {
// Initialize the component, or in the case of React, render the component
new MyComponent();
// The above should cause the `console.log` line to print out the
// new mocked value of 30
});
it('mocks the value of MY_CONSTANT for this test,', () => {
// Set up the spy. You can then use any jest mocking method
// (e.g. `mockReturnValue()`) on it
const mySpy = jest.spyOn(allConstants, 'MY_CONSTANT', 'get')
mySpy.mockReturnValue(15);
new MyComponent();
// The above should cause the `console.log` line to print out the
// new mocked value of 15
});
One of the way for mock variables is the follow solution:
For example exists file ./constants.js with constants:
export const CONSTATN_1 = 'value 1';
export const CONSTATN_2 = 'value 2';
There is also a file of tests ./file-with-tests.spec.js in which you need to do mock variables.
If you need to mock several variables you need to use jest.requireActual to use the real values of the remaining variables.
jest.mock('./constants', () => ({
...jest.requireActual('./constants'),
CONSTATN_1: 'mock value 1',
}));
If you need to mock all variables using jest.requireActual is optional.
jest.mock('./constants', () => ({
CONSTATN_1: 'mock value 1',
CONSTATN_2: 'mock value 2'
}));
Instead of Jest and having trouble with hoisting etc. you can also just redefine your property using "Object.defineProperty"
It can easily be redefined for each test case.
This is a pseudo code example based on some files I have:
From localization file:
export const locale = 'en-US';
In another file we are using the locale:
import { locale } from 'src/common/localization';
import { format } from 'someDateLibrary';
// 'MMM' will be formatted based on locale
const dateFormat = 'dd-MMM-yyyy';
export const formatDate = (date: Number) => format(date, dateFormat, locale)
How to mock in a test file
import * as Localization from 'src/common/localization';
import { formatDate } from 'src/utils/dateUtils';
describe('format date', () => {
test('should be in Danish format', () => {
Object.defineProperty(Localization, 'locale', {
value: 'da-DK'
});
expect(formatDate(1589500800000)).toEqual('15-maj-2020');
});
test('should be in US format', () => {
Object.defineProperty(Localization, 'locale', {
value: 'en-US'
});
expect(formatDate(1589500800000)).toEqual('15-May-2020');
});
});
in typescript, you can not overwrite constant value but; you can overwrite the getter function for it.
const mockNEXT_PUBLIC_ENABLE_HCAPTCHAGetter = jest.fn();
jest.mock('lib/constants', () => ({
...jest.requireActual('lib/constants'),
get NEXT_PUBLIC_ENABLE_HCAPTCHA() {
return mockNEXT_PUBLIC_ENABLE_HCAPTCHAGetter();
},
}));
and in the test use as
beforeEach(() => {
mockNEXT_PUBLIC_ENABLE_HCAPTCHAGetter.mockReturnValue('true');
});
Thank you all for the answers.
In my case this was a lot simpler than all the suggestions here
// foo.ts
export const foo = { bar: "baz" };
// use-foo.ts
// this is just here for the example to have a function that consumes foo
import { foo } from "./foo";
export const getFoo = () => foo;
// foo.spec.ts
import "jest";
import { foo } from "./foo";
import { getFoo } from "./use-foo";
test("foo.bar should be 'other value'", () => {
const mockedFoo = foo as jest.Mocked<foo>;
mockedFoo.bar = "other value";
const { bar } = getFoo();
expect(bar).toBe("other value"); // success
expect(bar).toBe("baz"); // fail
};
Hope this helps someone.
../../../common/constant/file (constants file path)
export const Init = {
name: "",
basePath: "",
description: "",
thumbnail: "",
createdAt: "",
endDate: "",
earnings: 0,
isRecurring: false,
status: 0,
};
jest file
jest.mock('../../../common/constant/file',()=>({
get Init(){
return {isRecurring: true}
}
}))
it('showActionbutton testing',()=>{
const {result} = renderHook(() => useUnsubscribe())
expect(result.current.showActionButton).toBe(true)
})
index file
import {Init} from ../../../common/constant/file
const useUsubscribe(){
const showActionButton = Init.isRecurring
return showActionButton
}
I solved this by initializing constants from ContstantsFile.js in reducers. And placed it in redux store. As jest.mock was not able to mock the contstantsFile.js
constantsFile.js
-----------------
const MY_CONSTANTS = {
MY_CONSTANT1: "TEST",
MY_CONSTANT2: "BEST",
};
export defualt MY_CONSTANTS;
reducers/index.js
-----------------
import MY_CONST from "./constantsFile";
const initialState = {
...MY_CONST
}
export const AbcReducer = (state = initialState, action) => {.....}
ABC.jsx
------------
import { useSelector } from 'react-redux';
const ABC = () => {
const const1 = useSelector(state) => state. AbcReducer. MY_CONSTANT1:
const const2 = useSelector(state) => state. AbcReducer. MY_CONSTANT2:
.......
Now we can easily mock the store in test.jsx and provide the values to constant that we want.
Abc.text.jsx
-------------
import thunk from 'redux-thunk';
import configureMockStore from 'redux-mock-store';
describe('Abc mock constants in jest', () => {
const mockStore = configureMockStore([thunk]);
let store = mockStore({
AbcReducer: {
MY_CONSTANT1 ="MOCKTEST",
MY_CONSTANT2 = "MOCKBEST",
}
});
test('your test here', () => { .....
Now when the test runs it will always pick the constant value form mock store.