Mocking vuex action using and Mocha - unit-testing

Question

I'm currently testing vuex module specifically actions.
Here's my code:
store/modules/users.js
export const state = () => ({
users: [],
})
export const mutations = () => ({
SET_USERS(state, users) {
console.log('Should reach Here');
state.users = users
}
})
export const actions = () => ({
getUsers({ commit }) {
return axios.get('/users')
.then(response => {
console.log('Reaching Here');
commit('SET_USERS', response.data.data.results)
})
.catch(error => {
console.log(error);
})
}
})
export const getters = () => {
users(state) {
return state.users;
}
};
Then when I test my actions:
tests/store/modules/users.js
it('should dispatch getUsers', () => {
mock.onGet('/users').reply(200, {
data: {
results: [
{ uid: 1, name: 'John Doe' },
{ uid: 2, name: 'Sam Smith' }
]
},
status: {
code: 200,
errorDetail: "",
message: "OK"
}
});
const commit = sinon.spy();
const state = {};
actions.getUsers({ commit, state });
expect(getters.users(state)).to.have.lengthOf(2);
});
when I try to run the test npm run dev it shows the console.log from action but from mutation SET_USERS it doesn't show the console.log
I'm referring to this documentation which I can use spy using sinon()
https://vuex.vuejs.org/guide/testing.html
How can I access the commit inside action to call mutation SET_USERS?

Answer 1

According to sinon docs
A test spy is a function that records arguments, return value, the value of this and exception thrown (if any) for all its calls. There are two types of spies: Some are anonymous functions, while others wrap methods that already exist in the system under test.
const commit = sinon.spy();
That is not the 'commit' from Vuex, you should test your mutation individually
actions.getUsers({ commit, state });
The commit argument is actually the spy, it will never trigger the mutation.
To test your mutation it could be something like this
mutations.SET_USERS(state, mockedUsers)
expect(state).to.have.lengthOf(mockedUsers.length)
...