I'm doing some integration testing in my Node app and at some point in my code I call the following function:
async.parallel([
function foo(callback){
setTimeout(function(){
//DO SOMETHING HERE;
callback(null, result);
}, 500);
},
function bar(callback){
//DO SOMETHING HERE;
callback(null, result);
}],
function(err, results){
//Process results here and continue
});
This code is part of a larger node app.
Now when I try to test my code with Mocha the test hangs because the timeout in foo() is never fired and therefore the parallel execution never finishes. When I remove the setTimeout the execution is completed just fine.
Here's the test code:
it("test something", function(done) {
request(app)
.post(requestUrl)
.send(testRequest)
.expect(200)
.end(function(err, res){
(res.body.text).should.equal('Hello World');
done();
});
});
What I tried:
Apparently, the clock is disbaled during testing so I tried using Sinon to simulate the passing of time but to no avail.
How can I solve this?
Well I had a similar problem today.
I was using var clock = sinon.useFakeTimers() without clock.restore().
To try that, you can use:
console.log(new Date().getTime());
console.log(new Date().getTime());
If you get twice the same value, it means that you may have change the clock.
Related
I have a function which resolves by taking a callback like function(error, result) { ... } as a parameter. I'm trying to use mocha to test this function, but the problem is that the function returns asynchronously, so there's no good place for me to put the done(). If I put inside my result handler, it takes too long and mocha times out. If I put it outside, the test always passes because the handler hasn't been called yet. Here is my code. What's the best way to get around this?
lbl.createLabels is a function that takes an array of customers, and a directory, and creates a bunch of files in that directory, and then asynchronously calls the callback of type: function(error, callback).
describe('Tests', () => {
it('returns a list of customer objects', (done) => {
lbl.createLabels(customers, __dirname + "/..", (err, result) => {
err.should.equal(undefined)
result.should.be.a('array')
result[0].should.have.property('id')
result[0].should.have.property('tracking')
result[0].should.have.property('pdfPath')
const a = {prop:3}
a.prop.should.be.an('array')
done() // putting done() here results in a timeout
})
done() // putting done here results in the test exiting before the callback gets called
})
})
Mocha's documentation has an entire section describing how to test asynchronous code:
https://mochajs.org/#asynchronous-code
Testing asynchronous code with Mocha could not be simpler! Simply invoke the callback when your test is complete. By adding a callback (usually named done) to it(), Mocha will know that it should wait for this function to be called to complete the test.
describe('User', function() {
describe('#save()', function() {
it('should save without error', function(done) {
var user = new User('Luna');
user.save(function(err) {
if (err) done(err);
else done();
});
});
});
});
I'm writing test cases with mocha in Nodejs and want to reset database data before running the tests. I'm using Knex as query builder for executing queries.
I wrote following logic:
describe('Activities:', function() {
before(funtion(){
activityDBOperations.deleteAll()
.then(function(){
// all records are deleted
});
});
it('it should add a record into Activities table: multiple time activity', function(done) {
activityDBOperations.addRecord(requestParams)
.then(function(data) {
expect(data.length > 0).to.equal(true);
done();
});
});
});
The problem is that test cases start executing and not waiting for deleteAll operation to finish. What I understand is since deleteAll is returning promise, the program execution move forward because of asynchronous nature of promises.
How can I make sure that test cases should run only when deleteAll has finished?
Either provide a callback to your before hook and call it in then:
before(function(done) {
activityDBOperations.deleteAll()
.then(function() {
// all records are deleted
done();
});
});
or, according to Mocha docs, just return a promise from before:
before(function() {
return activityDBOperations.deleteAll();
});
Add return statements so the Promises are actually returned.
I am trying to prototype a load testing scenario on socket interactions using Mocha and should.js. I have an array of user details which I want to authenticate using socket communication and wish to verify their responses. It works fine for a single user, however when I try to loop for multiple users - I end up with issues. Had gathered some inputs based on the post:Tests from looping through async JavaScript (Mocha) .
Below is the code snippet:
var users = [{name:'A',password:'password',expected:'success'},{name:'B',password:'badPass',expected:'failure'}];
describe('socket Interaction test' , function() {
function socketInteraction(users, done) {
client.emit('userAuthentication', {'name':users.name,'password':users.password}, function(callback) {
console.log('Emit' + users.name);
});
client.on('userAuthenticationResponse', function(response) {
console.log('Resp' + response.status + 'Expected' + users.expected);
response.status.should.equal(users.expected);
done();
});
}
it('Dummy', function(done) {
describe('Mutiple login Test Async', function() {
it('User Login Test', function(done) {
users.forEach(function(users, callback) {
console.log(users.name);
socketInteraction(users, function(err) {
if (err) {
return;
}
done();
});
});
});
});
});
});
The response I get upon running the test is:
socket Interaction test
✓ Dummy
Mutiple login Test Async
A
B
RespsuccessExpectedsuccess
✓ User Login Test
RespsuccessExpectedfailure
2 passing (43ms)
The second test has to fail. Not sure where I have messed up the code. Appreciate some pointers to fix this. Thanks.
The done Parma should be called in the second param of the async.forEach. The done you call in the loop function should be callback(), to tell async that just that user is finished.
You don't have the async finished callback yet at all.
Would have posted code but am on my phone. I can add later if it's not clear.
Given the following gulp tasks I'm able to successfully start the gulp, webpack and nodemon process, but the webpack tasks are open ended, so they will continue to fire the completion handler when their watch / compile cycle is complete.
The server task depends on the client task output, so I need these operations to be synchronous, hence the done
function onBuild(done) {
return function(err, stats) {
if(err) {
gutil.log('Error', err);
if(done) {
done();
}
} else {
Object.keys(stats.compilation.assets).forEach(function(key){
gutil.log('Webpack: output ', gutil.colors.green(key));
});
gutil.log('Webpack: ', gutil.colors.blue('finished ', stats.compilation.name));
if(done) {
done();
}
}
}
}
//dev watch
gulp.task('webpack-client-watch', function(done) {
webpack(devConfig[0]).watch(100, function(err, stats) {
onBuild(done)(err, stats);
});
});
gulp.task('webpack-server-watch', function(done) {
webpack(devConfig[1]).watch(100, function(err, stats) {
onBuild(done)(err, stats);
nodemon.restart();
});
});
gulp.task('webpack-watch',function(callback) {
runSequence(
'webpack-client-watch',
'webpack-server-watch',
callback
);
});
gulp.task('nodemon', ['webpack-watch'], function() {
nodemon({
script: path.join('server/dist/index.js'),
//ignore everything
ignore: ['*'],
watch: ['foo/'],
ext: 'noop'
}).on('restart', function() {
gutil.log(gutil.colors.cyan('Restarted'));
});
});
When I change a file, the watcher does its thing and gulp complains about the callback being called yet again.
[15:00:25] Error: task completion callback called too many times
I've looked at this, but not sure if its applicable.
Why might I be getting "task completion callback called too many times" in gulp?
Basically, I just want this to work synchronously and continuously without error.
gulp nodemon
This solved it for me: Just don't call the callback parameter in your webpack-watch task. Leave it out completely.
After that, the watcher works fine and fast without complaining.
If public folder exists in your application. Please remove and re-run, after you can see this issue resolved.
In my node application I'm using mocha to test my code. While calling many asynchronous functions using mocha, I'm getting timeout error (Error: timeout of 2000ms exceeded.). How can I resolve this?
var module = require('../lib/myModule');
var should = require('chai').should();
describe('Testing Module', function() {
it('Save Data', function(done) {
this.timeout(15000);
var data = {
a: 'aa',
b: 'bb'
};
module.save(data, function(err, res) {
should.not.exist(err);
done();
});
});
it('Get Data By Id', function(done) {
var id = "28ca9";
module.get(id, function(err, res) {
console.log(res);
should.not.exist(err);
done();
});
});
});
You can either set the timeout when running your test:
mocha --timeout 15000
Or you can set the timeout for each suite or each test programmatically:
describe('...', function(){
this.timeout(15000);
it('...', function(done){
this.timeout(15000);
setTimeout(done, 15000);
});
});
For more info see the docs.
I find that the "solution" of just increasing the timeouts obscures what's really going on here, which is either
Your code and/or network calls are way too slow (should be sub 100 ms for a good user experience)
The assertions (tests) are failing and something is swallowing the errors before Mocha is able to act on them.
You usually encounter #2 when Mocha doesn't receive assertion errors from a callback. This is caused by some other code swallowing the exception further up the stack. The right way of dealing with this is to fix the code and not swallow the error.
When external code swallows your errors
In case it's a library function that you are unable to modify, you need to catch the assertion error and pass it onto Mocha yourself. You do this by wrapping your assertion callback in a try/catch block and pass any exceptions to the done handler.
it('should not fail', function (done) { // Pass reference here!
i_swallow_errors(function (err, result) {
try { // boilerplate to be able to get the assert failures
assert.ok(true);
assert.equal(result, 'bar');
done();
} catch (error) {
done(error);
}
});
});
This boilerplate can of course be extracted into some utility function to make the test a little more pleasing to the eye:
it('should not fail', function (done) { // Pass reference here!
i_swallow_errors(handleError(done, function (err, result) {
assert.equal(result, 'bar');
}));
});
// reusable boilerplate to be able to get the assert failures
function handleError(done, fn) {
try {
fn();
done();
} catch (error) {
done(error);
}
}
Speeding up network tests
Other than that I suggest you pick up the advice on starting to use test stubs for network calls to make tests pass without having to rely on a functioning network. Using Mocha, Chai and Sinon the tests might look something like this
describe('api tests normally involving network calls', function() {
beforeEach: function () {
this.xhr = sinon.useFakeXMLHttpRequest();
var requests = this.requests = [];
this.xhr.onCreate = function (xhr) {
requests.push(xhr);
};
},
afterEach: function () {
this.xhr.restore();
}
it("should fetch comments from server", function () {
var callback = sinon.spy();
myLib.getCommentsFor("/some/article", callback);
assertEquals(1, this.requests.length);
this.requests[0].respond(200, { "Content-Type": "application/json" },
'[{ "id": 12, "comment": "Hey there" }]');
expect(callback.calledWith([{ id: 12, comment: "Hey there" }])).to.be.true;
});
});
See Sinon's nise docs for more info.
If you are using arrow functions:
it('should do something', async () => {
// do your testing
}).timeout(15000)
A little late but someone can use this in future...You can increase your test timeout by updating scripts in your package.json with the following:
"scripts": {
"test": "test --timeout 10000" //Adjust to a value you need
}
Run your tests using the command test
For me the problem was actually the describe function,
which when provided an arrow function, causes mocha to miss the
timeout, and behave not consistently. (Using ES6)
since no promise was rejected I was getting this error all the time for different tests that were failing inside the describe block
so this how it looks when not working properly:
describe('test', () => {
assert(...)
})
and this works using the anonymous function
describe('test', function() {
assert(...)
})
Hope it helps someone, my configuration for the above:
(nodejs: 8.4.0, npm: 5.3.0, mocha: 3.3.0)
My issue was not sending the response back, so it was hanging. If you are using express make sure that res.send(data), res.json(data) or whatever the api method you wanna use is executed for the route you are testing.
Make sure to resolve/reject the promises used in the test cases, be it spies or stubs make sure they resolve/reject.