Building a NodeJS REST API.
Trying to send load data from FireBase collection, then sending it to the user (as API response).
Looks like the problem is that it's not waits for the firebase fetch to resolve, but send back a response without the collection data. (tried to use ASYNC-AWAIT but its not working)
exports.getChatMessages = async (req, res, next) => {
const chatId = req.params.chatId
const getChatData = () => {
db
.collection('chats')
.doc(chatId)
.collection('messages')
.orderBy('timeStamp', 'asc')
.onSnapshot((snapshot) => {
snapshot.docs.forEach(msg => {
console.log(msg.data().messageContent)
return {
authorID: msg.data().authorID,
messageContent: msg.data().messageContent,
timeStamp: msg.data().timeStamp,
}
})
})
}
try {
const chatData = await getChatData()
console.log(chatData)
res.status(200).json({
message: 'Chat Has Found',
chatData: chatData
})
} catch (err) {
if (!err.statusCode) {
err.statusCode(500)
}
next(err)
}
}
As you can see, I've used 2 console.logs to realize what the problem, Terminal logs looks like:
[] (from console.logs(chatData))
All messages (from console.log(msg.data().messageContent))
Is there any way to block the code unti the firebase data realy fetched?
If I correctly understand, you want to send back an array of all the documents present in the messages subcollection. The following should do the trick.
exports.getChatMessages = async (req, res, next) => {
const chatId = req.params.chatId;
const collectionRef = db
.collection('chats')
.doc(chatId)
.collection('messages')
.orderBy('timeStamp', 'asc');
try {
const chatsQuerySnapshot = await collectionRef.get();
const chatData = [];
chatsQuerySnapshot.forEach((msg) => {
console.log(msg.data().messageContent);
chatData.push({
authorID: msg.data().authorID,
messageContent: msg.data().messageContent,
timeStamp: msg.data().timeStamp,
});
});
console.log(chatData);
res.status(200).json({
message: 'Chat Has Found',
chatData: chatData,
});
} catch (err) {
if (!err.statusCode) {
err.statusCode(500);
}
next(err);
}
};
The asynchronous get() method returns a QuerySnapshot on which you can call forEach() for enumerating all of the documents in the QuerySnapshot.
You can only await a Promise. Currently, getChatData() does not return a Promise, so awaiting it is pointless. You are trying to await a fixed value, so it resolves immediately and jumps to the next line. console.log(chatData) happens. Then, later, your (snapshot) => callback happens, but too late.
const getChatData = () => new Promise(resolve => { // Return a Promise, so it can be awaited
db.collection('chats')
.doc(chatId)
.collection('messages')
.orderBy('timeStamp', 'asc')
.onSnapshot(resolve) // Equivalent to .onSnapshot((snapshot) => resolve(snapshot))
})
const snapshot = await getChatData();
console.log(snapshot)
// Put your transform logic out of the function that calls the DB. A function should only do one thing if possible : call or transform, not both.
const chatData = snapshot.map(msg => ({
authorID: msg.data().authorID,
messageContent: msg.data().messageContent,
timeStamp: msg.data().timeStamp,
}));
res.status(200).json({
message: 'Chat Has Found',
chatData
})
Right now, getChatData is this (short version):
const getChatData = () => {
db
.collection('chats')
.doc(chatId)
.collection('messages')
.orderBy('timeStamp', 'asc')
.onSnapshot((snapshot) => {}) // some things inside
}
What that means is that the getChatData function calls some db query, and then returns void (nothing). I bet you'd want to return the db call (hopefully it's a Promise), so that your await does some work for you. Something along the lines of:
const getChatData = async () =>
db
.collection('chats')
// ...
Which is the same as const getChatData = async() => { return db... }
Update: Now that I've reviewed the docs once again, I see that you use onSnapshot, which is meant for updates and can fire multiple times. The first call actually makes a request, but then continues to listen on those updates. Since that seems like a regular request-response, and you want it to happen only once - use .get() docs instead of .onSnapshot(). Otherwise those listeners would stay there and cause troubles. .get() returns a Promise, so the sample fix that I've mentioned above would work perfectly and you don't need to change other pieces of the code.
I have got myself to the stage of unit testing, and to be honest, with all the different examples online I have got myself confused. I have a good understanding of Mocha & Chai, but Sinon is a different story.
So I have what I think is a pretty straight forward setup. I have a POST route that calls a controller. This controller is like so (removed some basic validation code)
const { createUser } = require('../services/user.service');
const apiResponse = require('../helpers/apiResponse');
const postUser = async (req, res) => {
const user = {
account_id: req.body.id,
status: req.body.status,
created_at: new Date(),
updated_at: new Date(),
};
const result = await createUser(user);
return apiResponse.successResponseWithData(res, 'User added.', result.affectedRows);
} catch (err) {
return apiResponse.errorResponse(res, err);
}
};
module.exports = {
postUser,
};
So all it really does is validate, and then creates a user object with the req and pass that to a service class. This services class does nothing more than pass the data to a database class.
const { addUserToDb } = require('../database/user.db');
const createUser = async (user) => {
try {
const createdUser = await addUserToDb(user);
return createdUser;
} catch (err) {
throw new Error(err);
}
};
module.exports = {
createUser,
};
I wont show the database class because what I want to focus on first is the controller, and then I can hopefully do the rest myself.
So from what I understand, I should be testing functions. If a function makes an external call, I should spy, mock, stub that call? I should only spy, mock or stub this functions dependencies, if one of the dependencies
has its own dependency (like the service module above having a database call dependency), this should be performed in another test? Sorry, just a few questions to help me understand.
Anyways, so I have created a user.controller.test.js file. I have not got far with it, but this is what I have so far
const chai = require('chai');
const sinon = require('sinon');
const { expect } = chai;
const faker = require('faker');
const controller = require('../controllers/user.controller');
const service = require('../services/user.service');
const flushPromises = () => new Promise(setImmediate);
describe('user.controller', () => {
describe('postUser', () => {
beforeEach(() => {
//I see a lot of code use a beforeEach, what should I be doing here?
});
it('should create a user when account_id and status params are provided', async () => {
const req = {
body: { account_id: faker.datatype.uuid(), status: 'true' },
};
const stubValue = {
id: faker.datatype.id(),
account_id: faker.datatype.uuid(),
status: 'true',
created_at: faker.date.past(),
updated_at: faker.date.past(),
};
});
});
});
If I am being totally honest I am pretty lost as to what I should be testing here. From my understanding, I need to mock the service module I think.
Could someone kindly provide some insight as to what I should be doing in this test?
Many thanks
Update
Thank you for your detailed response, I have managed to get a spy working which is a step forward. So I want to do a test on my service module, createUser method.
You can see that my createUser method takes a user Object as a parameter and passes this to a database module where it is inserted into the database and then the user object returned.
So when testing my service class, I need to mock this call to my database module.
const chai = require('chai');
const sinon = require('sinon');
const { expect } = chai;
const faker = require('faker');
const service = require('../services/user.service');
const database = require('../database/user.db');
describe('user.service', () => {
describe('createUser', () => {
it('should create a user when user object is provided', async () => {
const user = {
id: faker.datatype.string(),
status: 'true',
created_at: faker.date.past(),
updated_at: faker.date.past(),
};
const expectedUser = {
id: user.id,
status: user.status,
created_at: user.created_at,
updated_at: user.updated_at,
};
const mockedDatabase = sinon.mock(database);
mockedDatabase.expects('addUserToDb').once().withArgs(expectedUser);
await service.createUser(user);
mockedDatabase.verify();
mockedDatabase.restore();
});
});
});
When I test this, I seem to be getting this response, and it still seems to be inserting the record into my database.
ExpectationError: Expected addUserToDb({
id: 'yX7AX\\J&gf',
status: 'true',
created_at: 2020-06-03T03:10:23.472Z,
updated_at: 2020-05-24T14:44:14.749Z
}, '[...]') once (never called)
at Object.fail (node_modules\sinon\lib\sinon\mock-expectation.js:314:25)
Do you have any idea what I am doing wrong?
Thanks
before I try, I would like to suggest to drop the try/catch blocks everywhere, I will assume you're using expressJs in your Node application, and for such, take a look at express-promise-router as using that Router (instead the default one) will automatically catch anything it was thrown and you just need to focus on the code...
taking your example, you would write:
const { addUserToDb } = require('../database/user.db');
const createUser = async (user) => addUserToDb(user);
module.exports = {
createUser,
};
and
const { createUser } = require('../services/user.service');
const apiResponse = require('../helpers/apiResponse');
const postUser = async (req, res) => {
const { id: account_id, status } = res.body;
const result = await createUser({ account_id, status }); // set the date in the fn
return apiResponse.successResponseWithData(res, 'User added.', result.affectedRows);
};
module.exports = {
postUser,
};
if there's an error and in some place on the route an error is thrown, you will get a nice message back in the response with the error
regarding the code it self, seems a lot cleaner to read - keep in mind that code is for humans, the machine does not even care how you name your variables 😊
Now, regarding the tests ... I do tend to split things into 3 parts
unit tests: the functions itself, single one, like validation, helpers, etc
integration tests: when you call your API endpoint what should be returned
GUI tests (or end-to-end/e2e): applied when a GUI exists, will skip this for now
so in your case, the first thing to make sure of is what are you testing... and taking that, start from the small blocks (unit tests) and move up to the blocks that make sure all is glued together (e2e)
So all it really does is validate, and then creates a user object with the req and pass that to a service class. This services class does nothing more than pass the data to a database class.
Seems a great way to start, so it "validates" ... let's test our validation, let's pass null, undefined, string when all you want is int and so on, until we get a pretty good idea that whatever it passes, we will reply correctly with and without an error
Note I tend to use OpenAPI specs, which makes things easier for me as it provides 2 things
documentation of the endpoints
validation of the endpoints with a nice error message to the consumer
and yes, I always test some validation just to make sure it's working as expected, even though I trust the tool 100% 😜
So from what I understand, I should be testing functions.
well, an application is a group of functions, so all good there 💪
If a function makes an external call, I should spy, mock, stub that call?
I'll try to explain as best as I can what spies, stubs and mocks in Sinon are, please be gentle 🙏
Spies
they tell us information about functions calls, like, number of times called, arguments, return value, and more - they have two types, anonymous spies or spies that wrap methods in our code
function testMyCallback(callback) { callback(); }
describe('testMyCallback fn', function() {
it('should call the callback', function() {
const callbackSpy = sinon.spy(); // anonymous spy - no arguments
testMyCallback(callbackSpy);
expect(callbackSpy).to.have.been.calledOnce;
});
});
const user = {
setNname: function(name) {
this.name = name;
}
}
describe('setname fn', function() {
it('should be called with name', function() {
const setNameSpy = sinon.spy(user, 'setName'); // wrap method spy
user.setName('Katie');
expect(setNameSpy).to.have.been.calledOnce;
expect(setNameSpy).to.have.been.valledWith('Katie');
setNameSpy.restore(); // to remove the Spy and prevent future errors
});
});
Stubs
are power-spies, as they have all the functionality of Spies, but they replace the target function, they have methods that can return a specific value or throw a specific exception and a bit more
they are great to be used with your question regarding external calls, as they replace calls (so you can mock the call behavior and never use the original call)
the simplest of the examples is:
function isAdult(age) {
return age > 21;
}
describe('Sinon Stub Example', () => {
it('should pass', (done) => {
const isAdult = sinon.stub().returns('something');
isAdult(0).should.eql('something');
isAdult(0).should.not.eql(false);
done();
});
});
we've STUB'ed our function, and explicitly said it's a "function" that returns a string something... and for now on, we will never need to go to the function itself, as we have STUB it, we've replaced the real behavior with our own
another example of using STUBs when calling our API application in our integration tests
describe('when we stub our API call', () => {
beforeEach(() => {
this.get = sinon.stub(request, 'get'); // stub "request.get" function
});
afterEach(() => {
request.get.restore(); // remove our power-spy
});
describe('GET /api/v1/accounts', () => {
const responseObject = {
status: 200,
headers: {
'content-type': 'application/json'
}
};
const responseBody = {
status: 'success',
data: [
{
accountId: 1,
status: 'active'
},
{
accountId: 2,
status: 'disabled'
}
]
};
it('should return all accounts', (done) => {
// the 3 objects of our callback (err, res, body)
this.get.yields(null, responseObject, JSON.stringify(responseBody));
request.get(`${base}/api/v1/movies`, (err, res, body) => {
expect(res.statusCode).to.be.eql(200);
expect(res.headers['content-type']).to.contain('application/json');
body = JSON.parse(body);
expect(body).to.be.an('array').that.includes(2);
done();
});
});
});
});
you can also stub axios, but you will need a new library, either moxios, or proxyquire or more...
Mocks
are a bit similar to Stubs (our Power-Spies) but they can be used to replace whole objects and alter their behavior, they are mostly used when you need to stub more than one function from a single object - if all you need is to replace a single function, a stub is easier to use
Mocks can make things oversimplify and you could break your application without even knowing, so be aware...
a normally use is, for example
function setupNewAccount(info, callback) {
const account = {
account_id: info.id,
status: info.status,
created_at: new Date(),
updated_at: new Date()
};
try { Database.save(account, callback); }
catch (err) { callback(err); }
}
describe('setupNewAccount', function() {
it('', function() {
const account = { account_id: 1, status: 'active' };
const expectedAccount = {
account_id: account.id, status: account.status
};
const database = sinon.mock(Database);
database.expectes('save').once().withArgs(expectedAccount);
setupNewAccount(account, function() {});
database.verify();
database.restore();
});
});
something that we will keep forgetting is the .restore() part, and for that, there's a package (one more...) called sinon-test that will auto cleanup at the end of a test
I just hope it helped you with some of your questions and it's a bit clearer now 😏
BTW, for stubbing HTTP requests, I use nock as I think it's much easier to read and use than Sinon, especially for anyone that is reading code for the first time and has no experience in either Sinon or Nock...
I am wondering how to properly test Azure Functions with Jest. I have read the online documentation provided by MSoft but it's very vague, and brief. There are also some outdated articles I found that don't really explain much. Here is what I understand: I understand how to test normal JS async functions with Jest. And I understand how to test very simple Azure Functions. However I am not sure how to go about properly testing more complex Azure Functions that make multiple API calls, etc.
For example I have an HTTP Function that is supposed to make a few API calls and mutate the data and then return the output. How do I properly mock the API calls in the test? We only have one point of entry for the function. (Meaning one function that is exported module.exports = async function(context,req). So all of our tests enter through there. If I have sub functions making calls I can't access them from the test. So is there some clever way of mocking the API calls? (since actually calling API's during tests is bad practice/design)
Here is a sample of code to show what I mean
module.exports = async function (context, req)
{
let response = {}
if (req.body && req.body.id)
{
try
{
//get order details
response = await getOrder(context, req)
}
catch (err)
{
response = await catchError(context, err);
}
}
else
{
response.status = 400
response.message = 'Missing Payload'
}
//respond
context.res =
{
headers: { 'Content-Type': 'application/json' },
status: response.status,
body: response
}
};
async function getOrder(context, req)
{
//connection to db
let db = await getDb() // <- how to mock this
//retrieve resource
let item = await db.get...(id:req.body.id)... // <- and this
//return
return {'status':200, 'data':item}
}
Consider this (simplified) example.
src/index.js (Azure Function entry point):
const { getInstance } = require('./db')
module.exports = async function (context) {
// assuming we want to mock getInstance and db.getOrder
const db = await getInstance()
const order = await db.getOrder()
return order
}
src/db.js:
let db
async function getInstance() {
if (db === undefined) {
// connect ...
db = new Database()
}
return db
}
class Database {
async getOrder() {
return 'result from real call'
}
}
module.exports = {
getInstance,
Database,
}
src/__tests__/index.test.js:
const handler = require('../index')
const db = require('../db')
jest.mock('../db')
describe('azure function handler', () => {
it('should call mocked getOrder', async () => {
const dbInstanceMock = new db.Database() // db.Database is already auto-mocked
dbInstanceMock.getOrder.mockResolvedValue('result from mock call')
db.getInstance.mockResolvedValue(dbInstanceMock)
const fakeAzureContext = {} // fake the context accordingly so that it triggers "getOrder" in the handler
const res = await handler(fakeAzureContext)
expect(db.getInstance).toHaveBeenCalledTimes(1)
expect(dbInstanceMock.getOrder).toHaveBeenCalledTimes(1)
expect(res).toEqual('result from mock call')
})
})
> jest --runInBand --verbose
PASS src/__tests__/index.test.js
azure function handler
✓ should call mocked getOrder (4 ms)
For a complete quickstart, you may want to check my blog post
I have recently started writing tests and I don't have much experience.If any of the community member could point me in the right direction I would be really thankful. My scenario is simple I am half way through it but unable to solve my exact problem. Below is my code..
return generateServiceToken(req.body.appId, req.body.token, req.auth.userId)
.then(result => {
someService
.createCredentialsForUser(
req.auth.userId,
result.user.uid,
result.user.token
)
.then(result => {
return res.status(201).send(result);
});
})
.catch(error => {
return res.status(500).send({ error: `Credentials not valid - ${error}` });
});
The generateToken function is responsible to call a third party api to generate some credentials for their platform and return us the create credentials.
function generateServiceToken(appId: String, token: String, userId: String) {
return new Promise ((resolve, reject)=>{
const apiURL = `https://someapi.com/api/api.php?op=useradd&token=${token}&addr=${userId}&appid=${appId}`;
request.post(apiURL, (error, response, body) => {
const resp = JSON.parse(body);
if (resp.error) return reject(resp.error);
return resolve(resp);
});
});
}
Whereas, the someService.createCredentialsForUser function is responsible to save those credentials in database and return back the result in simple json format.
I am just stuck in stubbing someService.createCredentialsForUser function while writing the test case for happy-path
My test case is below..
describe.only("controllers/v3/some/", () => {
const c = {};
before(() => {
c.sandbox = sinon.createSandbox();
c.someServiceStub = c.sandbox
.stub(someService, "createCredentialsForUser")
.resolves(VALID_OUTPUT);
});
describe("when the request is valid", () => {
before(() => {
c.agent = setupApp(authenticationMiddleware(USER_ID));
return test(c, VALID_REQUEST_BODY);
});
it("should return 201", () => {
expect(c.response.statusCode).to.equal(201);
});
it("should call createCredentialsForUser", () => {
expect(c.stubs.createCredentialsForUser.called).to.equal(true);
});
});
});
The TestCase function is as follows..
function testCase(context, body = VALID_REQUEST_BODY) {
context.sandbox.resetHistory();
console.log(body.length);
const c = context;
return context.agent
.put(`/v3/some/`)
.send(body)
.then(r => {
c.response = r;
});
//.catch(err=>{c.response=err});
}
My someService.createCredentialsForUser function is responsible to save data into database I want to stub that that in a way that I could expect response return from generateServiceToken
I tried couples of ways which are as follows ..
First, I tried to stub that function in before() but no luck it fails with
error : IllegalArgumentError: init() must be called prior to use.
Second, I tried
c.response = c.sandbox.stub(someService, 'createCredentialsForUser').returns(Promise.resolve(r));
in my test function to stub with the value of resolved promise but no luck in this case it fails with the same error as mentioned above.
// Balance.jsx
...
updateToken () {
const parseResponse = (response) => {
if (response.ok) {
return response.json()
} else {
throw new Error('Could not retrieve access token.')
}
}
const update = (data) => {
if (data.token) {
this.data.accessTokenData = data
} else {
throw new Error('Invalid response from token api')
}
}
if (this.props.balanceEndpoint !== null) {
return fetch(this.props.accessTokenEndpoint, {
method: 'get',
credentials: 'include'
})
.then(parseResponse)
.then(update)
.catch((err) => Promise.reject(err))
}
}
componentDidMount () {
this.updateToken()
.then(() => this.updateBalance())
}
}
// Test
it('updates the balance', () => {
subject = mount(<Balance {...props} />)
expect(fetchMock.called('balance.json')).to.be.true
})
I can't figure out how to test the above using Mocha. The code is does work the method updateBalance is called and the fetch api call actually does happen, but the test still fails. If I call updateBalance() synchronously it passes... How do I tell the test to wait for the promise to resolve?
You don't really say what you want to test that the
method does, but if all you want to test is that the method resolves on a network call, then there is no need for Sinon or any of that, as this is all you need:
describe("BalanceComponent", () => {
it("should resolve the promise on a successful network call", () => {
const component = new BalanceComponent({any: 'props', foo: 'bar'});
// assumes you call a network service that returns a
// successful response of course ...
return component.updateToken();
});
});
This will test that the method actually works, but it is slow and is not a true unit test, as it relies on the network being there and that you run the tests in a browser that can supply you with a working implementation of fetch. It will fail as soon as you run it in Node or if the service is down.
If you want to test that the method actually does something specific, then you would need to to that in a function passed to then in your test:
it("should change the token on a successful network call", () => {
const component = new BalanceComponent({any: 'props', foo: 'bar'});
const oldToken = component.data.accessTokenData;
return component.updateToken().then( ()=> {
assert(oldToken !== component.data.accessTokenData);
});
});
If you want to learn how to test code like this without being reliant on there being a functioning link to the networked service you are calling, you can check out the three different techniques described in this answer.