Testing Redux : Should tests of a Reducer use actions or not? - unit-testing

Question

I'm currently learning Redux.
So far, as I'm discovering how to manage a state app, I don't want to focus on any integration with a framework (like React). I just want to well understand the idea and concepts behind Redux.
I followed courses given by Dan Abramov on egghead.io.
I like the way he explains by testing his app so I started playing with Redux the same way.
I built an app with Redux. Of course it has multiple reducers and actions.
I won't share any code here because it has no particular interest.
It's more a matter of how to deal with tests and Redux.
I don't know if it makes sense to test reducers with their corresponding actions of if I should mock the actions in my tests.
I started by mocking the actions because at first, I thought that it was a good idea to separate my tests and not having dependencies between reducers and actions. (and it's what I've seen in most tutorials. But in tutorials they often build small app).
Now, I figure out that I sometimes end up with a mock different than the corresponding action and even if my tests are fine, it could break in a real app when I'll use dispatch(myAction()) as it will be something different than exepected.
Should I use my actions in my reducers tests ?
Thanks a lot for any explanation about that.
EDIT : Some code to have a better explanation
REDUCER
case CREATE_USER_IN_PROJECT:
currentProject = state.filter(p => p.id === action.payload.idProjet)[0]
indexCurrentProject = state.indexOf(currentProject)
people = [
...currentProject.people,
action.payload.idUser
]
return [
...state.slice(0, indexCurrentProject),
Object.assign({}, currentProject, {people}),
...state.slice(indexCurrentProject + 1)
]
REDUCER'S TEST
it('CREATE_PROJECT if no project should only have the new project', done => {
let idNewProject = uuid.v4()
expect(
projects(undefined, {
type: CREATE_PROJECT,
payload: {
id: idNewProject,
name: 'New project !'
}
})
)
.toEqual([{
id: idNewProject,
name: 'New project !',
people: [],
money: '€',
operations: [],
archived: false,
closed: false
}])
done()
})
So here, instead of having
{
type: CREATE_PROJECT,
payload: {
id: idNewProject,
name: 'New project !'
}
}
Should I call my action createProject('New project !') ?

Answer 1

Thanks for the clarification. Turns out I misunderstood you in my comment. Here's a hopefully more helpful explanation.
You shouldn't use your actual actions, e.g. createProject('New project !'), in testing your reducers.
Reducers are simple state machines that take an input and return an output. Your tests should check they do exactly that, where:
input = previous state > output = next state. And yes it still count as unit-testing (I don't see why it wouldn't).
I found this a good read on how to test reducers