Unit test - React-redux reducers expected value - unit-testing

Question

I'm trying to make unit-test for redux reducer. And I would like to know the expected return value.
Currently I expected value to equal:
<"isConnected": false>
But I received:
<"0": <"isConnected": true>, "isConnected": false>
I found in the documentation two reducer syntax.
The first return an object:
<"0": <"isConnected": true>, "isConnected": false>
And the second an array:
[<"isConnected": false>]
What is the value that should be returned by a correct reducer ?
My package.json:
{
"name": "app",
"version": "0.1.0",
"private": true,
"dependencies": {
"react": "^16.3.2",
"react-dom": "^16.3.2",
"react-scripts": "1.1.4"
},
"scripts": {
"start": "react-scripts start",
"build": "react-scripts build",
"test": "react-scripts test --env=jsdom",
"eject": "react-scripts eject"
},
"devDependencies": {
"enzyme": "^3.3.0",
"enzyme-adapter-react-16": "^1.1.1",
"react-test-renderer": "^16.3.2"
}
}
My reducer:
import * as types from '../actions/actionsTypes'
const initialState = {
isConnected : true
};
const appReducer = ( state = initialState, action) => {
switch (action.type) {
case types.OPEN_CONNECTION :
return {
...state,
isConnected : true
};
case types.CLOSE_CONNECTION :
return {
...state,
isConnected : false
};
default:
return state
}
};
export default appReducer;
My test:
it('appReducer Test', () => {
expect(appReducer([{isConnected : false}], {type: types.OPEN_CONNECTION})).toEqual({isConnected : true})
})

Answer 1

I received this:
<"0": <"isConnected": true>, "isConnected": false>
Because i gived initialState as an array in my test:
[{isConnected : false}]
The correct syntax for the test is:
expect(appReducer({isConnected : false}, {type: types.OPEN_CONNECTION})).toEqual({isConnected : true})