I want to ask how to write unit test for this function. I've tried to mock it with mock-fs with keep getting the undefined for the result. Sorry I'm new to JavaSCript.
async getAllSongs(): String[] {
const songs = await readdir(this.storageDirectory);
return songs;
}
Okay it looks like your function is part of an object/class but since I am not 100%, i will use a contrived example.
Lets assume that in my sample.js file, I have some code like so:
//sample.js
const fs = require("fs").promises;
async function getAllSongs() {
const songs = await fs.readdir(".");
return songs;
}
module.exports = { getAllSongs };
To mock fs.readdir, you can use jest.mock and replace it with a function which return a promise since thats essentially what fs.readdir does.
//sample.test.js
const fs = require("fs").promises;
const { getAllSongs } = require("./sample.js");
fs.readdir = jest.fn(() => Promise.resolve(["lol.js", "lmao.js", "wow.txt"]));
test("tests stuff", async () => {
const result = await getAllSongs();
expect(result).toEqual(["lol.js", "lmao.js", "wow.txt"]);
});
Because i stubbed out fs.readdir with a fake function from jest, when getAllSongs is executed, jest will use my fake function instead of the original implementation.
Related
I am writing unit test for my auth.service module validateReader unit,
async validateReader(username: string, password: string): Promise<any> {
const reader = await this.readerService.findOne(username);
const match = await bcrypt.compare(password, reader.password);
if (match) {
const { password, ...result } = reader.toJSON();
this.logger.info(
`Reader ${reader.username} username & password validation passed`,
);
return result;
}
this.logger.warn(`Incorrect password in reader ${reader.username} login`);
return null;
}
I tried to mock readerService.findOne function as following:
jest
.spyOn(readerService, 'findOne')
.mockImplementationOnce(() => Promise.resolve(readerStub()));
but did not work, always got error - Cannot spy the findOne property because it is not a function; I think the reason is the returned value must be mongoose document object (need toJSON() method), but my readerStub() just return a reader object, missing lots of document properties. Is there anyway I can set up stub for document & reader? And maybe my analysis is wrong, there is other reason to got this error.
Following is my mock readerService:
export const ReaderService = jest.fn().mockReturnValue({
register: jest.fn().mockResolvedValue(readerStub()),
findOne: jest.fn().mockResolvedValue(readerStub()),
getProfile: jest.fn().mockResolvedValue(readerStub()),
updateProfile: jest.fn().mockResolvedValue(readerStub()._id),
changePwd: jest.fn().mockResolvedValue(readerStub().username),
login: jest.fn().mockResolvedValue(accessTokenStub()),
tokenRefresh: jest.fn().mockReturnValue(accessTokenStub()),
logout: jest.fn().mockResolvedValue(readerStub()._id),
});
Im five hours trying solve it, doesn't work nothing. I wanna test bloc class that use stream and sink data after load data from internet. The use case test work well but the bloc class was a huge headache today, this already work on app, but the test I really dont know how to solve
file bloc.dart
class Bloc {
final UseCase _useCase;
Bloc(this._useCase);
final _controller = StreamController.broadcast();
Stream get stream => _controller.stream;
doSomething() async {
ResponseModel responseModel = await _useCase.call();
_controller.sink.add(responseModel);//<-- I would like test this
}
dispose() {
_controller.close();
}
}
This is the unit test class bloc_test.dart
class UseCaseMock extends Mock implements UseCase {}
main() {
UseCase useCase;
Bloc bloc;
setUp(() async {
useCase = UseCaseMock();
bloc = Bloc(useCase);
});
tearDown(() {
bloc.dispose();
});
group('Test Bloc', () {
test('load stuff must sink Response ', () async {
when(useCase.call())
.thenAnswer((_) async => ResponseModel('id','name'));
//FIRST I TRY It, DOESNT WORK
// await expectLater( bloc.stream, emits(isA<ResponseModel>()));
bloc.stream.listen((response) {
//print(response) <-----return null I THINK HERE IS THE PROBLEM
expect(response, isA<ResponseModel>());
});
await bloc.doSomething();
});
});
}
Please, would you know how to solve it? Thanks
Solved here
Solved! my usecase has a method "call" with an optional parameter
Future<ResponseModel> call( {String value });
I was mocking wrong as below
when(useCase.call()) <----------------here is the error
.thenAnswer((_) async => ResponseModel('id','name'));
Inside true Bloc class(not a pseudocode that I had posted) I execute a usecase using the parameter
// this is the true doSomething() method on my app
loadCoupons(String storeId) async {
final result = await searchCouponUseCase(storeId: storeId);
_controller.sink.add(result);
}
And the solution is:
Mock using optional parameter(if it will be called)! I was testing without parameter because when putting "any" inside the test like a when( useCase.call( any))... not compile.
when(useCase.call( value: '' )) <-----solved
.thenAnswer((_) async => ResponseModel('id','name'));
You can run your async operation before using expectLater for assertion. Also remove the await from bloc.doSomething() as it times out otherwise.
This will work.
test('load stuff must sink Response ', () async {
when(useCase.call())
.thenAnswer((_) async => ResponseModel('id','name'));
bloc.doSomething();
await expectLater(bloc.stream, emits(isA<Response>()));
});
Sorry if this seems a dumb question. I'm learning clean architecture as dictated by Rob Martin, and I've having a tiny bit of trouble writing one of my tests.
I wrote a couple functions in a Hive repo. Here's the code
import 'package:hive/hive.dart';
import 'package:movie_browser/features/SearchMovie/domain/entities/movie_detailed_entity.dart';
abstract class HiveMovieSearchRepoAbstract {
Future<void> cacheMovieDetails(MovieDetailed movie);
Future<MovieDetailed> getCachedMovieDetails(String id);
}
// const vars to prevent misspellings
const String MOVIEDETAILSBOX = "MovieDetailedBox";
const String SEARCHBOX = "SearchBox";
class HiveMovieSearchRepo implements HiveMovieSearchRepoAbstract {
Box movieDetailsBox = Hive.box(MOVIEDETAILSBOX) ?? null;
// TODO implement searchbox
// final searchBox = Hive.box(SEARCHBOX);
Future<void> cacheMovieDetails(MovieDetailed movie) async {
/// expects a MovieDetailed to cache. Will cache that movie
movieDetailsBox ?? await _openBox(movieDetailsBox, MOVIEDETAILSBOX);
movieDetailsBox.put('${movie.id}', movie);
}
Future<MovieDetailed> getCachedMovieDetails(String id) async {
/// expects a string id as input
/// returns the MovieDetailed if cached previously
/// returns null otherwise
movieDetailsBox ?? await _openBox(movieDetailsBox, MOVIEDETAILSBOX);
return await movieDetailsBox.get('$id');
}
_openBox(Box box, String type) async {
await Hive.openBox(type);
return Hive.box(type);
}
}
I can't think of how to test this? I want two cases, one where the box is already opened, and one case where it isn't.
Specifically, it's these lines I want to test
movieDetailsBox ?? await _openBox(movieDetailsBox, MOVIEDETAILSBOX);
_openBox(Box box, String type) async {
await Hive.openBox(type);
return Hive.box(type);
}
I thought about mocking the Box object then doing something like....
when(mockHiveMovieSearchRepo.getCachedMovieDetails(some_id)).thenAnswer((_) async => object)
but wouldn't that bypass the code I want tested and always show as positive?
Thanks so much for the help
i don't know if i fully understand your question but you can try something like this
abstract class HiveMovieSearchRepoAbstract {
Future<void> cacheMovieDetails(MovieDetailed movie);
Future<MovieDetailed> getCachedMovieDetails(String id);
}
// const vars to prevent misspellings
const String MOVIEDETAILSBOX = "MovieDetailedBox";
const String SEARCHBOX = "SearchBox";
class HiveMovieSearchRepo implements HiveMovieSearchRepoAbstract {
final HiveInterface hive;
HiveMovieSearchRepo({#required this.hive});
#override
Future<void> cacheMovieDetails(MovieDetailed cacheMovieDetails) async {
/// expects a MovieDetailed to cache. Will cache that movie
try {
final moviedetailbox = await _openBox(MOVIEDETAILSBOX);
moviedetailbox.put('${movie.id}', movie);
} catch (e) {
throw CacheException();
}
}
Future<MovieDetailed> getCachedMovieDetails(String id) async {
/// expects a string id as input
/// returns the MovieDetailed if cached previously
/// returns null otherwise
try {
final moviedetailbox = await _openBox(MOVIEDETAILSBOX);
if (moviedetailbox.containsKey(boxkeyname)) {
return await movieDetailsBox.get('$id');
}
return null;
} catch (e) {
return CacheException();
}
}
Future<Box> _openBox(String type) async {
try {
final box = await hive.openBox(type);
return box;
} catch (e) {
throw CacheException();
}
}
}
And to test it you can do something like this
class MockHiveInterface extends Mock implements HiveInterface {}
class MockHiveBox extends Mock implements Box {}
void main() {
MockHiveInterface mockHiveInterface;
MockHiveBox mockHiveBox;
HiveMovieSearchRepo hiveMovieSearchRepo;
setUp(() {
mockHiveInterface = MockHiveInterface();
mockHiveBox = MockHiveBox();
hiveMovieSearchRepo = HiveMovieSearchRepo(hive: mockHiveInterface);
});
group('cacheMoviedetails', () {
test(
'should cache the movie details',
() async{
//arrange
when(mockHiveInterface.openBox(any)).thenAnswer((_) async => mockHiveBox);
//act
await hiveMovieSearchRepo.cacheMovieDetails(tcacheMovieDetails);
//assert
verify(mockHiveBox.put('${movie.id}', tmovie));
verify(mockHiveInterface.openBox("MovieDetailedBox"));
});
});
group('getLocalCitiesAndCountriesAtPage', () {
test('should when', () async {
//arrange
when(mockHiveInterface.openBox(any))
.thenAnswer((realInvocation) async => mockHiveBox);
when(mockHiveBox.get('$id'))
.thenAnswer((realInvocation) async => tmoviedetails);
//act
final result =
await hiveMovieSearchRepo.getCachedMovieDetails(tId);
//assert
verify(mockHiveInterface.openBox(any));
verify(mockHiveBox.get('page${tpage.toString()}'));
expect(result, tmoviedetails);
});
});
}
You should add some tests also for the CacheExeption().
Hope this help you.
So, I wrote this post 9 months. Stackoverflow just sent me a notification saying it's a popular question, so I'll answer it for anyone else wondering the same thing
Easy way to make this testable is change Box to an arg passed into the class, like so
abstract class ClassName {
final Box movieDetailsBox;
final Box searchBox;
ClassName({
this.moveDetailsBox,
this.searchBox,
});
}
this makes the boxes mockable and testable
You should mock the hive interface and box;
I would like let the mock method enable different responses for consecutive calls to the same method.
I found that Sinon has onCall, it allowed I can stub method like below,
let stubCall = sandbox.stub(Math, 'random');
stubCall.onCall(0).returns(Promise.resolve(0));
stubCall.onCall(1).returns(Promise.resolve(-1));
but I don't know how to let this work on AWS mock framework like this.
AWS.mock('CloudFormation', 'describeStacks', Promise.resolve(stackResponse));
I tried
AWS.mock('CloudFormation', 'describeStacks', Promise.resolve(stackResponse)).onCall(0).returns(Promise.resolve(res));
and
let mockCall = AWS.mock('CloudFormation', 'describeStacks', Promise.resolve(res));
mockCall.onCall(0).returns(Promise.resolve(res));
both of them didn't work.
I found people discuss this issue , mentioned since this aws-mock use sinon, it should able to use onCall. Is anyone use it successfully?
Since I use promise, I don't know what else I can do to return the different response for the same method has been called several times.
First, set the AWS SDK instance to be mocked
const sinon = require('sinon');
const AWS_Mock = require('aws-sdk-mock');
const AWS_SDK = require('aws-sdk');
AWSMock.setSDKInstance(AWS_SDK);
Configure stub that will be called
const stub = sinon.stub();
stub.onCall(0).returns(1);
stub.onCall(1).returns(2);
Mock Service method
Make sure that you're mocking the exact signature of the method.
AWSMock.mock('CloudFormation', 'describeStacks', function(params, cb) {
cb(null, stub());
});
Our Mocked method in action
const cf = new AWS_SDK.CloudFormation();
cf.describeStacks({}, (err, data) => {
if(err) {
console.err(err);
}
console.log(data); // 1
});
cf.describeStacks({}, (err, data) => {
if (err) {
console.err(err);
}
console.log(data); // 2
});
I'm trying to write a basic unit test to work on the function below, but can't get it to work. How do I test that something like a proper npm-express response is returned?
I already looked at Using Sinon to stub chained Mongoose calls, https://codeutopia.net/blog/2016/06/10/mongoose-models-and-unit-tests-the-definitive-guide/, and Unit Test with Mongoose, but still can't figure it out. My current best guess, and the resulting error, is below the function to be tested. If possible, I don't want to use anything but Mocha, Sinon, and Chai.expect (i.e. not sinon-mongoose, chai-as-expected, etc.). Any other advice, like what else I can/should test here, is welcome. Thank you!
The function to be tested:
function testGetOneProfile(user_id, res) {
Profiles
.findOne(user_id)
.exec()
.then( (profile) => {
let name = profile.user_name,
skills = profile.skills.join('\n'),
data = { 'name': name, 'skills': skills };
return res
.status(200)
.send(data);
})
.catch( (err) => console.log('Error:', err));
}
My current best-guess unit test:
const mongoose = require('mongoose'),
sinon = require('sinon'),
chai = require('chai'),
expect = chai.expect,
Profile = require('../models/profileModel'),
foo = require('../bin/foo');
mongoose.Promise = global.Promise;
describe('testGetOneProfile', function() {
beforeEach( function() {
sinon.stub(Profile, 'findOne');
});
afterEach( function() {
Profile.findOne.restore();
});
it('should send a response', function() {
let mock_user_id = 'U5YEHNYBS';
let expectedModel = {
user_id: 'U5YEHNYBS',
user_name: 'gus',
skills: [ 'JavaScript', 'Node.js', 'Java', 'Fitness', 'Riding', 'backend']
};
let expectedResponse = {
'name': 'gus',
'skills': 'JavaScript, Node.js, Java, Fitness, Riding, backend'
};
let res = {
send: sinon.stub(),
status: sinon.stub()
};
sinon.stub(mongoose.Query.prototype, 'exec').yields(null, expectedResponse);
Profile.findOne.returns(expectedModel);
foo.testGetOneProfile(mock_user_id, res);
sinon.assert.calledWith(res.send, expectedResponse);
});
});
The test message:
1) testGetOneProfile should send a response:
TypeError: Profiles.findOne(...).exec is not a function
at Object.testGetOneProfile (bin\foo.js:187:10)
at Context.<anonymous> (test\foo.test.js:99:12)
This is a bit of a tricky scenario. The problem here is that the findOne stub in your test returns the model object - instead, it needs to return an object which contains a property exec which in turn is a promise-returning function that finally resolves into the model value... yeah, as mentioned, it's a bit tricky :)
Something like this:
const findOneResult = {
exec: sinon.stub().resolves(expectedModel)
}
Profile.findOne.returns(findOneResult);
You also need to have the status function on the response object return an object containing a send function
//if we set up the stub to return the res object
//it returns the necessary func
res.status.returns(res);
I think you shouldn't need to change anything else in the test and it might work like that. Note that you sinon 2.0 or newer for the resolves function to exist on the stub (or you can use sinon-as-promised with sinon 1.x)
This post goes into a bit more detail on how you can deal with complex objects like that:
https://codeutopia.net/blog/2016/05/23/sinon-js-quick-tip-how-to-stubmock-complex-objects-such-as-dom-objects/