I'm trying to unit test a simple http REST client using mocha and chai libraries for Node.js with this code:
var chai = require('chai');
var asrt = require('chai').assert;
var client = require('../index');
describe('#Do successful', function () {
it('should pass when schema, host and port are provided', function () {
client.do('http:', 'localhost', '8080', '', function (result) {
console.log("starting assertions");
asrt.isAbove(result.items.length,0);
// ... other assertions
});
});
});
when I run the test with npm test, the test "passes" but the line that logs "starting assertions" is never printed, because the client.do function callback is never called, but I see that the server properly received the request and responded.
I'm obviously missing something, but I can't understand what in particular. Please notice that:
1) a very similar piece of code used in a non-test file produces the expected outcome (which is: the callback is called and the result data if filled with the response data).
2) Again, I'm testing a client, not a server, so I suppose I shuldn't use the done() function (but I tried as well, and didn't work).
Have you any hint on how to fix this? Thanks
Assuming that client.do is asynchronous because what you described is inline with the test executing, firing of asynchronous request, and not waiting for the response.
In this case the solution IS to use an asynchronous test with the done parameter:
var chai = require('chai');
var asrt = require('chai').assert;
var client = require('../index');
describe('#Do successful', function () {
it('should pass when schema, host and port are provided', function (done) {
client.do('http:', 'localhost', '8080', '', function (result) {
console.log("starting assertions");
asrt.isAbove(result.items.length,0);
// ... other assertions
// TEST WAITS FOR TIMEOUT OR UNTIL done() IS CALLED
done();
});
});
});
Related
I would like to test my simple API that has /groups URL.
I want to make an API request to that URL (using Axios) before all tests begin and make the response visible to all test functions.
I am trying to make the response visible but not able to make it work. I followed a similar case with filling out the DB upfront but no luck with my case.
My simple test file below:
var expect = require('chai').expect
var axios = require('axios')
var response = {};
describe('Categories', function() {
describe('Groups', function() {
before(function() {
axios.get(config.hostname + '/groups').then(function (response) {
return response;
})
});
it('returns a not empty set of results', function(done) {
expect(response).to.have.length.greaterThan(0);
done();
})
});
});
I tried also a sligh modification of before function:
before(function(done) {
axios.get(config.hostname + '/groups')
.then(function (response) {
return response;
}).then(function() {
done();
})
});
but no luck too.
The error I am getting is simply that response isn't changing nor is visible within it. AssertionError: expected {} to have property 'length'
Summarising: How can I pass response from axios inside to in()?
Your first form is incorrect, because you're not returning the chained promise. As such, mocha has no way of knowing when your before is finished, or even that it's async at all. Your second form will solve this problem, but since axios.get already returns a promise, it's kind of a waste not to use mocha's built-in promise support.
As for making the response visible in the it, you need to assign it to a variable in a scope that will be visible within the it.
var expect = require('chai').expect
var axios = require('axios')
var response;
describe('Categories', function() {
describe('Groups', function() {
before(function() {
// Note that I'm returning the chained promise here, as discussed.
return axios.get(config.hostname + '/groups').then(function (res) {
// Here's the assignment you need.
response = res;
})
});
// This test does not need the `done` because it is not asynchronous.
// It will not run until the promise returned in `before` resolves.
it('returns a not empty set of results', function() {
expect(response).to.have.length.greaterThan(0);
})
});
});
I have some mocha tests I run with Nodejs to test a web server.
Many of the tests should cause the server to return an error, e.g. 400 Bad Request.
Currently the tests are peppered with many copies of the following code:
it('should respond with 400 (Bad Request)', function (){
expect(httpResponse.statusCode).to.equal(httpstatus.BAD_REQUEST);
});
Here's a simplified pseudocode example:
describe('When passing bad JSON data', function(){
var response
before(function(done){
callUrlToInsert(url, badJson, function(err, resp){
response = resp
done()
}
}
it('should respond with 400 (Bad Request)', function (){
expect(httpResponse.statusCode).to.equal(httpstatus.BAD_REQUEST)
})
}
This bugs me because as a programmer I avoid duplicate code wherever possible.
However, putting this into a function does not work:
function verifyItReturnedBadRequest400(httpResponse)
{
it('should respond with 400 (Bad Request)', function (){
expect(httpResponse.statusCode).to.equal(httpstatus.BAD_REQUEST);
});
}
because the call to it() doesn't test the assertion right then; my [limited] understanding is that it() adds the closure to the list of tests. So by the time that check is done, the httpResponse variable has gone out of scope. (I don't understand why that is the case, because in both cases there is a call to it(); why would it matter that in one case it's inside another level of function call? I'm probably missing something with regard to Javascript scoping.)
Is there a common way to avoid all this duplicate code? Or is everyone out there duplicating all their assertion code everywhere? This is my first foray into Mocha so I am probably missing something obvious.
Also, bonus points for explaining why doesn't the function approach work?
Thanks!
There is an article on wiki about this.
https://github.com/mochajs/mocha/wiki/Shared-Behaviours
I guess you have some bugs in your test. Placing it() into wrapper function works fine. Here's a small working demo.
'use strict';
const assert = require('assert');
const xEqualsOne = () => {
it('should be equal 1', () => {
assert.equal(this.x, 1);
});
};
describe('async number', () => {
this.x = 0;
before(done => {
this.x++
setTimeout(done, 100);
});
xEqualsOne();
});
I guess your code looks something like this:
describe('When passing bad JSON data', function(){
var response
before(function(done){
callUrlToInsert(url, badJson, function(err, resp){
response = resp
done()
}
}
verifyItReturnedBadRequest400(httpResponse)
}
Think about it like this:
it() creates a test.
All the calls to it happen before any tests are actually run (you have to create tests before you run them)
The function passed to `before' is run after the tests have been created, but before they are run.
verifyItReturnedBadRequest400 calls it, to create a test, but you're passing in httpResponse right then before any tests have run, so before hasn't run yet either.
You could continue to use that sort of pattern, but you'll need to put the httpresponse in a container so you can pass a reference to it:
describe('When passing bad JSON data', function(){
var data = {};
before(function(done){
callUrlToInsert(url, badJson, function(err, resp){
data.response = resp
done()
}
}
verifyItReturnedBadRequest400(data)
}
and then your verifyItReturnedBadRequest400 becomes:
function verifyItReturnedBadRequest400(data) {
it('should respond with 400 (Bad Request)', function (){
expect(data.response.statusCode).to.equal(httpstatus.BAD_REQUEST);
});
}
Brand new to testing. Trying to figure out why mocha is passing this test when it should be failing.
var assert = require('assert');
var nock = require('nock');
var https = require('https');
describe('thing', function() {
describe('foo', function () {
it('makes the correct https call to API', function () {
nock('https://example.com')
.get('/foo')
.reply(404);
https.get('https://example.com/foo', function (response) {
console.log(response.statusCode); // returns 404
assert.equal(response.statusCode, 200); //passes
});
});
});
});
Mocha, just like any other [properly-written] Node.js module/app, runs asynchronously out of the box. Because your https call takes longer to execute than the entire Mocha test, Mocha never has a chance to perform its assertions before the process completes.
That said, Mocha tests also supports a callback that let you execute long-running activities before performing your assertions:
var assert = require('assert');
var nock = require('nock');
var https = require('https');
describe('thing', function() {
describe('foo', function () {
it('makes the correct https call to API', function (done) {
nock('https://example.com')
.get('/foo')
.reply(404);
https.get('https://example.com/foo', function (response) {
console.log(response.statusCode); // returns 404
assert.equal(response.statusCode, 200); //passes
done();
});
});
});
});
I have the following route (express) for which I'm writing an integration test.
Here's the code:
var q = require("q"),
request = require("request");
/*
Example of service wrapper that makes HTTP request.
*/
function getProducts() {
var deferred = q.defer();
request.get({uri : "http://localhost/some-service" }, function (e, r, body) {
deferred.resolve(JSON.parse(body));
});
return deferred.promise;
}
/*
The route
*/
exports.getProducts = function (request, response) {
getProducts()
.then(function (data) {
response.write(JSON.stringify(data));
response.end();
});
};
I want to test that all the components work together but with a fake HTTP response, so I am creating a stub for the request/http interactions.
I am using Chai, Sinon and Sinon-Chai and Mocha as the test runner.
Here's the test code:
var chai = require("chai"),
should = chai.should(),
sinon = require("sinon"),
sinonChai = require("sinon-chai"),
route = require("../routes"),
request = require("request");
chai.use(sinonChai);
describe("product service", function () {
before(function(done){
sinon
.stub(request, "get")
// change the text of product name to cause test failure.
.yields(null, null, JSON.stringify({ products: [{ name : "product name" }] }));
done();
});
after(function(done){
request.get.restore();
done();
});
it("should call product route and return expected resonse", function (done) {
var writeSpy = {},
response = {
write : function () {
writeSpy.should.have.been.calledWith("{\"products\":[{\"name\":\"product name\"}]}");
done();
}
};
writeSpy = sinon.spy(response, "write");
route.getProducts(null, response);
});
});
If the argument written to the response (response.write) matches the test passes ok. The issue is that when the test fails the failure message is:
"Error: timeout of 2000ms exceeded"
I've referenced this answer, however it doesn't resolve the problem.
How can I get this code to display the correct test name and the reason for failure?
NB A secondary question may be, could the way the response object is being asserted be improved upon?
The problem looks like an exception is getting swallowed somewhere. The first thing that comes to my mind is adding done at the end of your promise chain:
exports.getProducts = function (request, response) {
getProducts()
.then(function (data) {
response.write(JSON.stringify(data));
response.end();
})
.done(); /// <<< Add this!
};
It is typically the case when working with promises that you want to end your chain by calling a method like this. Some implementations call it done, some call it end.
How can I get this code to display the correct test name and the reason for failure?
If Mocha never sees the exception, there is nothing it can do to give you a nice error message. One way to diagnose a possible swallowed exception is to add a try... catch block around the offending code and dump something to the console.
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.