I'm trying to write unit tests for parts of my Node app. I'm using Mongoose for my ORM.
I've searched a bunch for how to do testing with Mongoose and Node but not come with anything. The solutions/frameworks all seem to be full-stack or make no mention of mocking stuff.
Is there a way I can mock my Mongoose DB so I can return static data in my tests? I'd rather not have to set up a test DB and fill it with data for every unit test.
Has anyone else encountered this?
I too went looking for answers, and ended up here. This is what I did:
I started off using mockery to mock out the module that my models were in. An then creating my own mock module with each model hanging off it as a property. These properties wrapped the real models (so that child properties exist for the code under test). And then I override the methods I want to manipulate for the test like save. This had the advantage of mockery being able to undo the mocking.
but...
I don't really care enough about undoing the mocking to write wrapper properties for every model. So now I just require my module and override the functions I want to manipulate. I will probably run tests in separate processes if it becomes an issue.
In the arrange part of my tests:
// mock out database saves
var db = require("../../schema");
db.Model1.prototype.save = function(callback) {
console.log("in the mock");
callback();
};
db.Model2.prototype.save = function(callback) {
console.log("in the mock");
callback("mock staged an error for testing purposes");
};
I solved this by structuring my code a little. I'm keeping all my mongoose-related stuff in separate classes with APIs like "save", "find", "delete" and no other class does direct access to the database. Then I simply mock those in tests that rely on data.
I did something similar with the actual objects that are returned. For every model I have in mongoose, I have a corresponding class that wraps it and provides access-methods to fields. Those are also easily mocked.
Also worth mentioning:
mockgoose - In-memory DB that mocks Mongoose, for testing purposes.
monckoose - Similar, but takes a different approach (Implements a fake driver). Monckoose seems to be unpublished as of March 2015.
Related
Im trying to get familiar with using MOQ and mocking in general. So I want to test an api controller which uses an assembly which serves as a repository for getting/updating data etc.
eg a structure like this.
HomeController
Index
Repository.GetSomeData (returns JSON object)
This repository class has an interface, and that is what is injected via the .net core startup class. The method in this case, GetSomeData does a number of steps via calls to the Db, as well as reading a file from the file system, parsing it and moving it off to another folder.
Question: How can a "mocked" Repository work without doing the things that the "real" object does? All the examples I see are simple addition, returning strings etc.
When you mock something like your repository, you going to stub out methods on the repository to return some canned result. Calls to those methods on the repository mock, then, bypass the real methods and instead just do what you've stubbed.
Essentially, you need to first identity what methods will be utilized. Then, you should determined appropriate responses those methods should return based on the particular scenario you're attempting to unit test. Then, you create the mock and add stubs for those methods with those responses.
The whole point of mocking is to remove variables, so you're intentionally trying to get to the "happy path": the set of internal responses that put the action in the state you need it to be in for specific test you're conducting.
I am working in a Python project where I have some classes that extend from another that gives them an "ORM Layer" to call it in some way. These objects are persistent in the DB when their attributes change.
The big problem comes when I want to test the logics of these objects, it really gets close to impossible to mock everything and I'm going nuts.
Is there any strategy or directives to test this kind of situation? Thanks.
The generic strategy is not to test the database or other frameworks. Assume that they work.
I don't know which persistance / ORM framework is used. But a good strategy here is monkey patching: Instead of mocking the framework, you overwrite methods in your test that try to access the database with empty ones:
def nop(*args, **kw): pass
ORFramework.BaseObject.messThingsUp = nop
where messThingsUp is a method of the class BaseObject that you want to get rid of.
I am sorry if this question is already been asked. I am very new to Unit Testing and I am suppose to use Rhino for mocking.
So the problem is...I have a method to test and that method is suppose to do retrive some data based on input parameter and return as datatable.
It also do some calculation for finding out which stored procedure should be called and with which set of parameters.
I issue is that, When I call the method with mock objects....it throws an error at date from database retrival line of code as object is not set to an instanse. That is expected as their is no data retruning from database since we are mocking it.
so what could be done it that case.
Seems like it is a good time to introduce Repository Pattern.
If you introduce than, the logic to generate query to DB and the logic to read data from DB will be encapsulated in the Repository.
In this case you can mock/stub the Repository in your tests and you can unit test all the classes, which use Repository, without creation test DB at all.
The Repository mock will verify whether incoming parameters are correct.
And the Repository stub will return any test-specific data which you need for each particular test.
I have a number of simple controller classes that use Doctrine's entity manager to retrieve data and pass it to a view.
public function indexAction() {
$pages = $this->em->getRepository('Model_Page')->findAll();
$this->view->pages = $pages;
}
What exactly should we be testing here?
I could test routing on the action to ensure that's configured properly
I could potentially test that the appropriate view variables are being set, but this is cumbersome
The findAll() method should probably be in a repository layer which can be tested using mock data, but then this constitutes a different type of test and brings us back to the question of
What should we be testing as part of controller tests?
Controller holds core logic for your application. Though simple "index" controller actions don't have any specific functions, those that verify/actively use data and generate viewmodels have pretty much the most functionality of the system.
For example, consider login form. Whenever the login data is posted, controller should validate login/password and return: 1) to index page whenever logins are good. Show welcome,{user} text. 2) to the login page saying that login is not found in db. 3) to the login page saying that password is not found in db.
These three types of outputs make perfect test cases. You should validate that correct viewmodels/views are being sent back to the client with the appropriate actions.
You shouldn't look at a controller like at something mysterious. It's just another code piece, and it's tested as any other code - any complicated logic that gives business-value to the user should be tested.
Also, I'd recommend using acceptance testing with framework like Cucumber to generate meaningful test cases.
Probably the controller is the hardest thing to test, as it has many dependencies. In theory you should test it in full isolation, but as you already seen - it has no sense.
Probably you should start with functional or acceptance test. It tests your controller action in a whole. I agree with previous answer, that you should try acceptance testing tools. But Cucumber is for Ruby, for PHP you can try using Codeception. It makes tests simple and meaningful.
Also on a Codeception page there is an article on how to test sample controllers.
I'm writing some unit tests in my project and I have a datacontext dependency on the controller containing the methods I'd like to test.
I'm using Ninject to inject the dependency and Moq to create my mock datacontext. My DI makes use of an interface IDataContext which my dbml impliments and is used through out the injection process.
In my unit test I'm creating my mock datacontext as follows:
var mock = new Mock<IDataContext>();
var myController = new MyController(mock.Object);
This throws a Object reference not set to an instance of an object. exception on the second line whilst executing the datacontexts constructor.
I'm clearly missing a fundamental piece in setting this up however most of the Moq examples I've seen involve some kind of test against the mocked object using Setup().
Am I going about this the right way? Should I be creating a mock of my IDataContext interface or something else?
haha,
the answer came while i was reading through emad's blog on unit testing in ASP.Net MVC.
I'm guessing that you didn't add the connection string to the app.config of your test project right? :)
And that's the database dependency way because you're still not mocking the database end.
So if you want to do that, you need to google up for some codes, there are a few ways to do that.
i find these few references below to be quite useful, but since i don't really have a need to mock the database end, i'm just using my test DB server for now.
link