Redux reducer unit test - unit-testing

Question

And I'm trying to make unit-test for redux reducer. But i'm struggling with receiving the same expected and equal results.
const initState = {};
export default function (state = initState, action) {
const newState = { ...state };
switch (action.type) {
case CREATE_TYPE:
return {
...state,
[action.customType.id]: {
...action.customType
}
};
default:
return state;
}
}
My test. Seems that problem in customType: { id: 'test-id' }
describe('reducer', () => {
it('should return the initial state', () => {
const state = reducer(undefined, { type: 'unknown' });
expect(state).toEqual({});
});
it('should handle CREATE_TYPE', () => {
expect(reducer({ test: true }, {
type: CREATE_TYPE,
customType: { id: 'test-id' },
id: 'test-id'
})).toEqual({
'test-id': 'test-type',
'test': true
});
});
});

Answer 1

Often it helps to spell everything out.
That way you can clearly understand what your expected outcome needs to be.
it('should handle CREATE_TYPE', () => {
const initialState = { test: true };
const customType = { id: 'test-id' };
const action = {
type: CREATE_TYPE,
customType: customType,
id: customType.id
};
const result = reducer(initialState, action);
const expectedResult = {
test: true,
[customType.id]: customType
};
expect(result).toEqual(expectedResult);
});
It then becomes easier to see exactly where the issue lies.

Answer 2

You are exprecting back from your reducer :
{
...state,
[action.customType.id]: {
...action.customType
}
which if you send
{
type: CREATE_TYPE,
customType: { id: 'test-id' },
id: 'test-id'
}
Will equate itself to :
{
...state,
'test-id' : { id: 'test-id' }
}
and you are evaluating it equal to
{
...state,
'test-id': 'test-type'
}
I don't know how you are expecting to format your state via your reducer - but the way your reducer is set up now will not provide the state you are expecting. I don't know what you are expecting because i don't see the node or value 'test-type' anywhere else in your provided code. It looks like you just have some syntactical errors maybe?