How to mock functions in the same module using Jest?

by

An alternative solution can be importing the module into its own code file and using the imported instance of all of the exported entities. Like this:

import * as thisModule from './module';

export function bar () {
    return 'bar';
}

export function foo () {
    return `I am foo. bar is ${thisModule.bar()}`;
}

Now mocking bar is really easy, because foo is also using the exported instance of bar:

import * as module from '../src/module';

describe('module', () => {
    it('foo', () => {
        spyOn(module, 'bar').and.returnValue('fake bar');
        expect(module.foo()).toEqual('I am foo. bar is fake bar');
    });
});

Importing the module into its own code looks strange, but due to the ES6’s support for cyclic imports, it works really smoothly.

More Related Contents:

  1. How can I mock an ES6 module import using Jest?
  2. jquery (or pure js) simulate enter key pressed for testing
  3. How can I mock the JavaScript window object using Jest?
  4. Jest: Timer and Promise don’t work well. (setTimeout and async function)
  5. How can I use Jest to spy on a method call?
  6. How to change the behaviour of a mocked import?
  7. Simulate a button click in Jest
  8. What functions should I mock during unit testing
  9. Jest spyOn function called
  10. Is it possible to put test files under pages directory in Next.js?
  11. How to select option in drop down protractorjs e2e tests
  12. how to use Protractor on non angularjs website?
  13. Fetching values from email in protractor test case
  14. Mocking globals in Jest
  15. Using require with relative paths
  16. Can you write async tests that expect toThrow?
  17. How to mock localStorage in JavaScript unit tests?
  18. How can I mock dependencies for unit testing in RequireJS?
  19. How to reuse beforeEach/afterEach in Jasmine JS?
  20. Suites vs Specs Protractor
  21. How to unit test a Node.js module that requires other modules and how to mock the global require function?
  22. Protractor: element.getText() returns an object and not String
  23. jest unexpected token when importing css
  24. How to mock Axios with Jest?
  25. Jest: how to mock console when it is used by a third-party-library?
  26. How to mock dependencies for unit tests with ES6 Modules
  27. Jest – SyntaxError: Cannot use import statement outside a module
  28. Mock inner axios.create()
  29. Mocking dayjs extend
  30. Protractor: Scroll down

Leave a Comment