I have already mocked Firebase onAuthStateChanged, so tests work flawlessly but I have this use case, in which it set's the user inside:
const [isSignedIn, setIsSignedIn] = useState<boolean>(false);
const [displayName, setDisplayName] = useState<string | null>('');
const auth = getAuth();
onAuthStateChanged(auth, (user) => {
console.log('OnAuthStateChanged USER', user);
if (user) {
setDisplayName(user.email);
setIsSignedIn(true);
} else {
setIsSignedIn(false);
setDisplayName('');
}
I know that you can easily mock what it returns, but I don't know how to deal with the "insides" of a function if that it's even possible.
I need to set the state specifically since the DrawerNavigator will show different options depending if the user is signedIn or not:
{isSignedIn && (
<>
<Drawer.Screen name='Dashboard' component={Dashboard} />
</>
)}
{!isSignedIn && (
<>
<Drawer.Screen name='Welcome' component={Welcome} />
<Drawer.Screen name='CreateAccount' component={CreateAccount} />
<Drawer.Screen name='Login' component={Login} />
</>
)}
I can test the functionality but only on the default state as it is initialized, how can I make this work? Or is there any other change of how I set the state in which this could be testable?
Here it is also how I'm mocking firebase/auth module right now:
/**
* Firebase
*/
jest.mock('firebase/auth', () => {
return {
getAuth: () => jest.fn(),
onAuthStateChanged: () => jest.fn(),
};
});
Assuming you want to emulate the delay that occurs when signing in a user:
onAuthStateChanged with or without a user.currentUser property on the FirebaseAuth instance passed in to it should be updated at the same time.The mock below assumes you aren't using more than one app at a time. If so, getting specific app instances must be implemented.
/**
* Firebase Auth Module
*/
jest.mock('firebase/auth', () => {
const authInstance = {
// while handshaking with the Firebase Auth servers, currentUser
// is null, regardless if someone is logged in or not.
currentUser: null
};
const mockedUserInfo = Object.freeze({ // force read-only
// mocked user info here - display name, email, etc
email: 'example@example.com'
});
// container for attached callbacks and state variables
const authChangeCallbacks = [];
let authCurrentUserInfo = mockedUserInfo;
let authTimer = null;
let authTimerCompleted = false;
// invoke all callbacks with current data
const fireOnChangeCallbacks = () => {
authMock.currentUser = authCurrentUserInfo;
callbacks.forEach((cb) => {
try {
cb(mockedUserInfo)); // invoke any active listeners
} catch (err) {
console.error('Error invoking callback', err);
}
});
authTimerCompleted = true;
}
authInstance.signOut = () => { // signInWithX will look similar to this
authCurrentUserInfo = null;
fireOnChangeCallbacks();
};
return {
getAuth: jest.fn(() => authInstance),
onAuthStateChanged: jest.fn((authMock, onChangeCallback) => {
if (!authTimer) {
// increase this delay to emulate slower connections
authTimer = setTimeout(fireOnChangeCallbacks, 2000);
}
callbacks.push(onChangeCallback);
const unsubscriber = () => {
const foundIndex = callbacks.indexOf(onChangeCallback);
if (foundIndex > -1) callbacks.splice(foundIndex, 1);
}
if (authTimerCompleted) {
// auth is "resolved" already, fire callback immediately
onChangeCallback(mockedUserInfo);
}
return unsubscriber;
})
};
});