Jest Mock for testing Google Cloud Firestore
A simple way to mock calls to Cloud Firestore, allowing you to assert that you are requesting data correctly.
This is not a pseudo-database -- it is only for testing you are interfacing with firebase/firestore the way you expect.
This library is NOT feature complete with all available methods exposed by Firestore.
Small, easy to grok pull requests are welcome, but please note that there is no official roadmap for making this library fully featured.
- Mock Firestore
⚠️ WARNING⚠️ - Table of Contents
- What's in the Box
- Installation
- Usage
- Contributing
- Code of Conduct
- About Upstatement
This library provides an easy to use mocked version of firestore.
With npm:
npm install --save-dev firestore-jest-mock
With yarn:
yarn add --dev firestore-jest-mock
The default method to use is mockFirebase
, which returns a jest mock, overwriting firebase
and firebase-admin
. It accepts an object with two pieces:
database
-- A mock of your collectionscurrentUser
-- (optional) overwrites the currently logged in user
Example usage:
const { mockFirebase } = require('firestore-jest-mock');
// Create a fake Firestore with a `users` and `posts` collection
mockFirebase({
database: {
users: [
{ id: 'abc123', name: 'Homer Simpson' },
{ id: 'abc456', name: 'Lisa Simpson' },
],
posts: [{ id: '123abc', title: 'Really cool title' }],
},
});
If you are using TypeScript, you can import mockFirebase
using ES module syntax:
import { mockFirebase } from 'firestore-jest-mock';
This will populate a fake database with a users
and posts
collection. This database is read-only by default, meaning that any Firestore write calls will not actually persist across invocations.
Now you can write queries or requests for data just as you would with Firestore:
const { mockCollection } = require('firestore-jest-mock/mocks/firestore');
test('testing stuff', () => {
const firebase = require('firebase'); // or import firebase from 'firebase';
const db = firebase.firestore();
return db
.collection('users')
.get()
.then(userDocs => {
// Assert that a collection ID was referenced
expect(mockCollection).toHaveBeenCalledWith('users');
// Write other assertions here
});
});
In TypeScript, you would import mockCollection
using ES module syntax:
import { mockCollection } from 'firestore-jest-mock/mocks/firestore';
The other mock functions may be imported similarly.
If you use @google-cloud/firestore
, use mockGoogleCloudFirestore
instead of mockFirebase
in all the documentation.
const { mockGoogleCloudFirestore } = require('firestore-jest-mock');
mockGoogleCloudFirestore({
database: {
users: [
{ id: 'abc123', name: 'Homer Simpson' },
{ id: 'abc456', name: 'Lisa Simpson' },
],
posts: [{ id: '123abc', title: 'Really cool title' }],
},
});
const { mockCollection } = require('firestore-jest-mock/mocks/firestore');
test('testing stuff', () => {
const { Firestore } = require('@google-cloud/firestore');
const firestore = new Firestore();
return firestore
.collection('users')
.get()
.then(userDocs => {
expect(mockCollection).toHaveBeenCalledWith('users');
expect(userDocs.docs[0].data().name).toEqual('Homer Simpson');
});
});
Note: Authentication with @google-cloud/firestore
is not handled in the same way as with firebase
.
The Auth
module is not available for @google-cloud/firestore
compatibility.
If you use @react-native-firebase/firestore
, use mockReactNativeFirestore
instead of mockFirebase
in all the documentation.
const { mockReactNativeFirestore } = require('firestore-jest-mock');
mockReactNativeFirestore({
database: {
users: [
{ id: 'abc123', name: 'Homer Simpson' },
{ id: 'abc456', name: 'Lisa Simpson' },
],
posts: [{ id: '123abc', title: 'Really cool title' }],
},
});
const { mockCollection } = require('firestore-jest-mock/mocks/firestore');
test('testing stuff', () => {
const { Firestore } = require('@react-native-firebase/firestore');
const firestore = new Firestore();
return firestore
.collection('users')
.get()
.then(userDocs => {
expect(mockCollection).toHaveBeenCalledWith('users');
expect(userDocs.docs[0].data().name).toEqual('Homer Simpson');
});
});
Note: Authentication with @react-native-firebase/firestore
is not handled in the same way as with firebase
.
The Auth
module is not available for @react-native-firebase/firestore
compatibility.
A common Firestore use case is to store data in document subcollections. You can model these with firestore-jest-mock like so:
const { mockFirebase } = require('firestore-jest-mock');
// Using our fake Firestore from above:
mockFirebase({
database: {
users: [
{
id: 'abc123',
name: 'Homer Simpson',
},
{
id: 'abc456',
name: 'Lisa Simpson',
_collections: {
notes: [
{
id: 'note123',
text: 'This is a document in a subcollection!',
},
],
},
},
],
posts: [{ id: '123abc', title: 'Really cool title' }],
},
});
Similar to how the id
key defines a document object to firestore-jest-mock, the _collections
key defines a subcollection. You model each subcollection structure in the same way that database
is modeled above: an object keyed by collection IDs and populated with document arrays.
This lets you model and validate more complex document access:
const { mockCollection, mockDoc } = require('firestore-jest-mock/mocks/firestore');
test('testing stuff', () => {
const firebase = require('firebase');
const db = firebase.firestore();
return db
.collection('users')
.doc('abc456')
.collection('notes')
.get()
.then(noteDocs => {
// Assert that a collection or document ID was referenced
expect(mockCollection).toHaveBeenNthCalledWith(1, 'users');
expect(mockDoc).toHaveBeenCalledWith('abc456');
expect(mockCollection).toHaveBeenNthCalledWith(2, 'notes');
// Write other assertions here
});
});
The job of the this library is not to test Firestore, but to allow you to test your code without hitting Firebase servers or booting a local emulator. Since this package simulates most of the Firestore interface in plain JavaScript, unit tests can be quick and easy both to write and to execute.
Take this example:
function maybeGetUsersInState(state) {
const query = firestore.collection('users');
if (state) {
query = query.where('state', '==', state);
}
return query.get();
}
We have a conditional query here. If you pass state
to this function, we will query against it; otherwise, we just get all of the users. So, you may want to write a test that ensures you are querying correctly:
const { mockFirebase } = require('firestore-jest-mock');
// Import the mock versions of the functions you expect to be called
const { mockCollection, mockWhere } = require('firestore-jest-mock/mocks/firestore');
describe('we can query', () => {
mockFirebase({
database: {
users: [
{
id: 'abc123',
name: 'Homer Simpson',
state: 'connecticut',
},
{
id: 'abc456',
name: 'Lisa Simpson',
state: 'alabama',
},
],
},
});
test('query with state', async () => {
await maybeGetUsersInState('alabama');
// Assert that we call the correct Firestore methods
expect(mockCollection).toHaveBeenCalledWith('users');
expect(mockWhere).toHaveBeenCalledWith('state', '==', 'alabama');
});
test('no state', async () => {
await maybeGetUsersInState();
// Assert that we call the correct Firestore methods
expect(mockCollection).toHaveBeenCalledWith('users');
expect(mockWhere).not.toHaveBeenCalled();
});
});
In this test, we don't necessarily care what gets returned from Firestore (it's not our job to test Firestore), but instead we try to assert that we built our query correctly.
If I pass a state to this function, does it properly query the
users
collection?
That's what we want to answer.
In jest, mocks will not reset between test instances unless you specify them to.
This can be an issue if you have two tests that make an asseration against something like mockCollection
.
If you call it in one test and assert that it was called in another test, you may get a false positive.
Luckily, jest offers a few methods to reset or clear your mocks.
- clearAllMocks() clears all the calls for all of your mocks. It's good to run this in a
beforeEach
to reset between each test
jest.clearAllMocks();
- mockClear() this resets one specific mock function
mockCollection.mockClear();
The where
clause in the mocked Firestore will not actually filter the data at all.
We are not recreating Firestore in this mock, just exposing an API that allows us to write assertions.
It is also not the job of the developer (you) to test that Firestore filtered the data appropriately.
Your application doesn't double-check Firestore's response -- it trusts that it's always correct!
The default state of this mock is meant for basic testing that should cover most everyone.
However, you can pass an options
object to the mock to overwrite some default behavior.
const options = {
includeIdsInData: true,
mutable: true,
simulateQueryFilters: true,
};
mockFirebase(database, options);
By default, id's are not returned with the document's data.
Although you can declare an id when setting up your fake database, it will not be returned with data()
as that is not the default behavior of firebase.
However, a common practice for firestore users is to manually write an id
property to their documents, allowing them to query collectionGroup
by id.
Warning: Thar be dragons
By default, the mock database you set up is immutable.
This means it doesn't update, even when you call things like set
or add
, as the result isn't typically important for your tests.
If you need your tests to update the mock database, you can set mutable
to true
when calling mockFirebase
.
Calling .set()
on a document or collection would update the mock database you created.
This can make your tests less predictable, as they may need to be run in the same order.
Use with caution.
Note: not all APIs that update the database are supported yet. PRs welcome!
By default, query filters (read: where
clauses) pass through all mock Firestore data without applying the requested filters.
If you need your tests to perform where
queries on mock database data, you can set simulateQueryFilters
to true
when calling mockFirebase
.
Method | Use | Method in Firestore |
---|---|---|
mockCollection |
Assert the correct collection is being queried | collection |
mockCollectionGroup |
Assert the correct collectionGroup is being queried | collectionGroup |
mockDoc |
Assert the correct record is being fetched by id. Tells the mock you are fetching a single record | doc |
mockBatch |
Assert batch was called | batch |
mockBatchDelete |
Assert correct refs are passed | batch delete |
mockBatchCommit |
Assert commit is called. Returns a promise | batch commit |
mockGetAll |
Assert correct refs are passed. Returns a promise resolving to array of docs. | getAll |
mockUpdate |
Assert correct params are passed to update. Returns a promise | update |
mockAdd |
Assert correct params are passed to add. Returns a promise resolving to the doc with new id | add |
mockSet |
Assert correct params are passed to set. Returns a promise | set |
mockDelete |
Assert delete is called on ref. Returns a promise | delete |
mockUseEmulator |
Assert correct host and port are passed | useEmulator |
Method | Use | Method in Firestore |
---|---|---|
mockGet |
Assert get is called. Returns a promise resolving either to a single doc or querySnapshot | get |
mockWhere |
Assert the correct query is written. Tells the mock you are fetching multiple records | where |
mockLimit |
Assert limit is set properly | limit |
mockOrderBy |
Assert correct field is passed to orderBy | orderBy |
mockOffset |
Assert offset is set properly | offset |
mockStartAfter |
Assert startAfter is called | startAfter |
mockStartAt |
Assert startAt is called | startAt |
mockWithConverter |
Assert withConverter is called | withConverter |
Method | Use | Method in Firestore |
---|---|---|
mockArrayRemoveFieldValue |
Assert the correct elements are removed from an array | arrayRemove |
mockArrayUnionFieldValue |
Assert the correct elements are added to an array | arrayUnion |
mockDeleteFieldValue |
Assert the correct fields are removed from a document | delete |
mockIncrementFieldValue |
Assert a number field is incremented by the correct amount | increment |
mockServerTimestampFieldValue |
Assert a server Firebase.Timestamp value will be stored | serverTimestamp |
Method | Use | Method in Firestore |
---|---|---|
mockTimestampToDate |
Assert the call and mock the result, or use the default implementation | toDate |
mockTimestampToMillis |
Assert the call and mock the result, or use the default implementation | toMillis |
mockTimestampFromDate |
Assert the call and mock the result, or use the default implementation | fromDate |
mockTimestampFromMillis |
Assert the call and mock the result, or use the default implementation | fromMillis |
mockTimestampNow |
Assert the call and mock the result, or use the default implementation | now |
Method | Use | Method in Firestore |
---|---|---|
mockGetTransaction |
Assert transaction.get is called with correct params. Returns a promise | get |
mockGetAllTransaction |
Assert transaction.getAll is called with correct params. Returns a promise | get |
mockSetTransaction |
Assert transaction.set is called with correct params. Returns the transaction object | set |
mockUpdateTransaction |
Assert transaction.update is called with correct params. Returns the transaction object | update |
mockDeleteTransaction |
Assert transaction.delete is called with correct params. Returns the transaction object | delete |
Method | Use | Method in Firebase |
---|---|---|
mockCreateUserWithEmailAndPassword |
Assert correct email and password are passed. Returns a promise | createUserWithEmailAndPassword |
mockGetUser |
Assert correct user IDs are passed. Returns a promise | getUser |
mockDeleteUser |
Assert correct ID is passed to delete method. Returns a promise | deleteUser |
mockSendVerificationEmail |
Assert request for verification email was sent. Lives on the currentUser |
sendVerificationEmail |
mockCreateCustomToken |
Assert correct user ID and claims are passed. Returns a promise | createCustomToken |
mockSetCustomUserClaims |
Assert correct user ID and claims are set. | setCustomUserClaims |
mockSignInWithEmailAndPassword |
Assert correct email and password were passed. Returns a promise | signInWithEmailAndPassword |
mockSendPasswordResetEmail |
Assert correct email was passed. | sendPasswordResetEmail |
mockVerifyIdToken |
Assert correct token is passed. Returns a promise | verifyIdToken |
mockUseEmulator |
Assert correct emulator url is passed | useEmulator |
mockSignOut |
Assert sign out is called. Returns a promise | signOut |
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