Test of reducer returns the results which are not equal to expected-CodePudding

I try to test my reducer with react testing library and I don't understand why I get results that are not equal to the expected. Please could you explain to me?

my reducer

export const myReducer = (state = initialState, { type, payload }) => {
    switch (type) {
        case 'GET_DATA':
            return [...payload];
        default:
            return state;
    }
};

my test

import { mockedState } from 'mocks';

import {
    myReducer,
    GET_DATA,
} from 'store';

const initialState = []

describe('reducer', () => {

  it('should get data', () => {
    const getAction = {
      type: GET_DATA,
      payload: mockedState.data,
    };
    expect(myReducer(initialState, getAction )).toEqual([...mockedState.data]);
  });
})

CodePudding user response：

In your reducer, you are using a string "GET_DATA" in your switch case. But from the look of your test your action type is a variable GET_DATA. Try changing your reducer's first case to be

case GET_DATA: //remove the quotes

where GET_DATA is from 'store'.

Actually, I just remembered case for a switch statement must be a constant. So just make sure your GET_DATA from store is actually equal to "GET_DATA".

CodePudding user response：

The question seems to revolve around when an iterable a is not 'shallow' equal to [...a]. If a is an array that should always be the case but for any other iterable it's not.

I suspect mockedState.data is not an array in the failing test.

For example:

const a = 'hello';
const b = [...a];        // ["h","e","l","l","o"]

In this case a does not equal b.