Jest

Spying in automaitc node_module mocks

When you want to spy on methods of a module that was automatically mocked (via a file in the __mocks__ folder that was named after the module), jest will complain. To be able to do so, you can export the functions you want to spy on from said file.

Following is an exmple of a mock for react-native-keychain:

// __mocks__/react-native-keychain.js
export const setInternetCredentials = jest.fn()
export const getInternetCredentials = jest.fn()

This would allow us to do something like expect(Keychain.setInternetCredentials).toHaveBeenCalledTimes(1)

Note: react-native-keychain does not have a default export. This is why we are exporting seperate consts here. For a module with a default export, we would have to adapt accordingly.