CODEWITHSUNDEEP
javascriptreact-reduxjestjsreact-testing-library
JeffBaumgardt
JeffBaumgardt

Reputation: 1488

How can I mock all the named exports from a module, except one?

I have a redux file that contains my reducer and all of my actions via named exports.

export const reducer = (state, action) => ...

export myAction = action => {
    return {type: 'ACTION', action}
}
...

When in my test file I import the reducer and the actions. I have a renderWithRedux which takes in the reducer and creates a real store inside.

function renderWithRedux(ui, reducer = combineReducers(reducers), initialState = {}) {
    const store = createStore(reducer, initialState)
    const utils = render(<Provider store={store}>{ui}</Provider>)

    return {
        ...utils,
        store,
    }
}

The question I have is that the component I'm rendering is passed actions in the mapDispatchToProps in the connected component.

export default connect(mapStateToProps, { myAction })(MyComponent)

I want to mock the myAction in my particular use case this action would actually be a thunk and I want to see if the store updated.

The problem I have is how do I mock myAction but not the reducer. I've tried

jest.mock('./reducerFile', () => {
    return jest.fn().mockImplementation(() => {
        return {
            reducer: require.requireActual('./reducerFile').reducer,
            myAction: jest.fn()
        }
    })
})

But the reducer is still mocked somehow.

Is this even possible or am I just wanderlust.

Upvotes: 9

Views: 6043

Answers (3)

Krzysztof Grzybek
Krzysztof Grzybek

Reputation: 9416

You can try this workaround:

jest.mock('./reducerFile', () => {
  const moduleMock = jest.requireActual(
    './reducerFile'
  );

  return {
    ...moduleMock,
    myAction: jest.fn(),
  };
});

Upvotes: 16

Deepak
Deepak

Reputation: 2727

You can do something like I did, in your test file:

const yourModule = require('../path/to/yourModule');

yourModule.myFn = jest.fn();

This would mock the named export function in your module.

Upvotes: 0

tpdietz
tpdietz

Reputation: 1368

Unfortunately, you are out of luck. Jest mocks the entire module. It is not possible to partially mock a file. I personally would recommend splitting up the file to make testing easier for you.

See this discussion on github for an in-depth explanation as to why: https://github.com/facebook/jest/issues/936

Upvotes: 0

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