Now I see that constructor is a syntax sugar and it's nothing to do with Function.prototype.constructor, therefore stubbing it has no effect. Sinon.JS a quelques utilitaires utilisés en interne dans lib/sinon.js. But indeed, writing a little "How to" on this subject would help. Yes it is. Even with proxyquire, there is no way to stub the Panel's constructor to test that new Panel() was called with appropriate arguments when testing Carousel class (at least not with their latest code build), unless I'm missing something. Since the underlying implementation of _inherits includes: I think I can stub the __proto__ of Foo? Though in some more basic cases, you can get away with only using Sinon by modifying the module exports of the dependency. library dependencies). Doesn't trigger stubbed constructor. stub (redis, 'createClient') . Look into what MDN has to say on the constructor property. Run the following test, it will give AssertError: expected constructor to be called once but was called 0 times: Expected behavior Never test your code with connection to remote dependencies. It's interesting but it doesn't demonstrate how to stub or spy an instance method. In the following example, how can I verify that thing.doSomething is called once, with 1, 2 and 3? Since sinon.createStubInstance has been removed from latest versions of Sinon, I would suggest stubbing individual instance methods on the prototype, to achieve the desired effect. I didn't think about stubbing the prototype the way you did. If you want to read more about stub/mock/spy in Sinon I suggest to use this blog post. sinon-helpers. For JS built-in classes you'll probably be right to assume that they live in global. Related Posts: How to run node script from BASH? const publisherStub = { publish: sinon.stub() }; Now you have defined a contract for your code that is independent of the specific dependency you will be using in production. If you want to create a stub object of MyConstructor, but don’t want the constructor to be invoked, use this utility function. This behaves the same way as sinon.assert.neverCalledWith(spy, sinon.match(arg1), sinon.match(arg2), ...). See also Asynchronous calls. npm install karma-sinon-stub-promise – – save-dev Yes this is not stubbing the constructor but when used in conjunction with something like proxyquire, which you can use to mock module exports, you can replace the constructor of an external library with MyClass and check how the constructor is invoked. In the examples, we want to mock a constructor MyConstructor. Let’s find out! Create easily configurable sinon stubs that mimic constructors and keep track of their instances.. Usage Latest version published about 2 months ago. 'test sinon constructor spy with container'. var stub = sinon . Mocking imported class dependencies in Sinon.JS (with TypeScript) Kirien Eyma. I tried different ways, but the only way I could really spy on a constructor was the following: That looks like a usage question; please post it to StackOverflow and tag it with sinon, so the bigger community can help answer your questions. I wonder if I'm using sinon (v3.1.0) correctly, trying to stub constructors and if we can make this task simpler. What we as an org can do to improve the situation is to write tutorials and documentation, something that demands a bit of an effort, which is why we have an issue for tackling this (#1121). sinon-helpers. Je voulais me moquer de l'objet que le nouvel appel a créé. Replace MyConstructor by sinon.stub(MyConstructor). The spy will behave exactly like the original method (including when used as a constructor), but you will have access to data about all calls. If you want to test the interaction with the publisher, inject it in your constructor. Never test your code with connection to remote dependencies. @hyzhak We are trying to keep the GitHub issues list tidy and focused on bugs and feature discussions. Ref MDN. Importing stubConstructor function: import single function: import { stubConstructor } from "ts-sinon"; import as part of sinon singleton: import * as sinon from "ts-sinon"; const stubConstructor = sinon.stubConstructor; Object constructor stub (stub all methods): without passing predefined args to the constructor: To Reproduce Create easily configurable sinon stubs that mimic constructors and keep track of their instances.. But keep in mind they are just normal JS objects and normal JS functions, albeit with some Sinon.js sugar sprinkled on top. sinon-helpers. Object constructor stub example. Creating a link seam this way could be a possible solution: That is certainly one way. Unless your test runner reloads all files between every test (I don't know of any that does this, because that would be excruciatingly slow), then you're stuck with that value for all your tests. Let me know if I'm doing bad things, or if I can create a PR :D. The text was updated successfully, but these errors were encountered: I prefer using a link seam for stubbing constructors and verifying that a function uses the expected dependencies in the expected ways. Have a question about this project? By clicking “Sign up for GitHub”, you agree to our terms of service and With more complex fake objects like this, it’s easy to end up with messy tests with a lot of duplication. sinon library extension to stub whole object and interfaces - 1.2.0 - a TypeScript package on npm - Libraries.io The post targets developers who are coming to ES6 from environments that has features like … A lot more people follow that tag that will help you. Motivation. Motivation. To achieve this, I'm doing the following: Do you think that adding a method to sinon.stub that can achieve this makes sense? First test passes (stubbed constructor gets called). In other words if you do something like ... class Foo { constructor() {console.log('this shouldn\'t have been called')} // gets called } sinon.stub(Foo.prototype, 'constructor'); new Foo(); console.log(Foo.prototype.constructor.called); // false sinon.useFakeTimers() was breaking some of my tests for some reason, I had to stub Date.now() sinon.stub(Date, 'now').returns(now); In that case in the code instead of const now = new Date(); you can do. Causes the stub to throw the argument at the provided index. Mocking Time with sinon.js – The Chronicles of Nerdia, There are situations where new Date() or Date.now is used in to remember how to mock/stub or spy on Date.now / new Date with Jest. It’s not possible to stub the constructor itself due to language constraints. You just implemented the entire object to test as something that returns a stub. npm install sinon-stub-promise – – save-dev. But it doesn't seem to work: Your thinking is sound, but the implementation uses deprecated elements. Any help would be greatly appreciated. privacy statement. sinon.useFakeTimers() was breaking some of my tests for some reason, I had to stub Date.now() sinon.stub(Date, 'now').returns(now); In that case in the code instead of const now = new Date(); you can do. sinon-helpers. If updating from v1, please see updating from v1 to v2.. @RenWenshan This issue has appeared multiple times, but it doesn't have anything to do with Sinon in itself, but is simply due to a missing understanding of what the constructor keyword in ES6 refers to (hint: it shares very little with Function#constructor other than the name). @fatso83 Thanks for the gist. Recognized. http://sinonjs.org/how-to/link-seams-commonjs/. Pour réaliser les prochains tests, on aura besoin de stubs et de promesses, c’est pourquoi on utilisera sinon-stub-promise et son intégration dans karma karma-sinon-stub-promise . A concrete example using chai-spies to freeze the Date object (equivalent of creating a stub with Sinon): My original need was to stub the constructor of a class's parent class so I can test whether super was called, e.g. It has different properties. Create easily configurable sinon stubs that mimic constructors and keep track of their instances.. Just beware that one drawback with this approach is that your test-code may assume things about the API that does not hold. I didn't see any example with prototype or new operator in the doc (maybe I missed it). Community. This is creating a constructor that returns a function and testing if the returned function is called. Let’s think of getIngrediants as a function… I'd like to return a custom object which on depends on passed arguments. If applicable, add screenshots to help explain your problem. @fatso83 thank you so much for explaining this. Do the same using sinon.spy(MyConstructor) instead. This simple takes a function and stubs the function (without an Overload) since Stubs (unlike Spies) suppress the underlying implementation (so there is no point in providing the actual implementation as a parameter to the constructor) var stub = sinon. function buildToSend(repo) { const ... data.name, date: new Date(), }, }; } And I need to test it but i really can't find out how to mock/stub the new Date() constructor. const now = new Date(Date.now()); Or consider option of using moment library for date related stuff. Mocking constructors using node and chai/sinon I have a function like this. Using Sinon 4.4.2, I was able to mock an instance method like this: sinon.stub(MyClass.prototype, myMethod).resolves(tesObj) I needed a mock for a line that looked something like: let someData = await new MyClass(token).myMethod(arg1, arg2) A similar solution provided here: Stubbing a class method with Sinon… A quick search for "mocking Javascript class constructor" did lead me to some helpful answers. By clicking “Sign up for GitHub”, you agree to our terms of service and MIT. var stub = sinon . [] It's one of the best I found and I think even documentation of Sinon is not as good as this guys explanation. A stub is a spy with predetermined behavior.. We can use a stub to: Take a predetermined action, like throwing an exception; Provide a predetermined response; Prevent a specific method from being called directly (especially when it triggers undesired behaviors like HTTP requests) That knowledge will make it vastly easier to work with your ES6 (and later) code, as you know what is really happening. But how do I spy on classes properly? Sign in and stub/mock required call: sinon.stub(Backend, 'fetchData'); Mocking with Dependency Injection. sinon library extension to stub whole object and interfaces. In case you want to use this on Node, @stckvflw's answer can be adapted assuming you know the namespace of the constructor like @billy mentioned. That way, we can find out which parameters are used to create instances. You signed in with another tab or window. npm install ts-sinon. Thanks for the explanation! I am pulling my hair out trying to figure out how to mock a constructor using sinon. That's quite simple actually :) Create easily configurable sinon stubs that mimic constructors and keep track of their instances.. With link seams, you can control exactly when the code is being loaded, or if it's loaded at all. No need to improve sinon, it supports this use case well enough, as you demonstrated it. Currently spies and stubs don't call original or stub function with new by design - even if they were called with new.The suggestion is to add this behaviour to them. [Feature request] fake constructor with stub#instantiate or something, // sinon.spy(() => sinon.createStubInstance(Thing)) can achieve this as well, 'should call Thing.prototype.doSomething with `1, 2, 3`'. Mocking constructors using node and chai/sinon I have a function like this. There is a reason the _inherits function you posted a snippet from tries to use Object.setPrototypeOf if available, only falling back to using __proto__ in really old browsers. This ticket looks like a usage question; please post it to StackOverflow and tag it with sinon, so the bigger community can help answer your questions. sinon 100 / 100; Package Health Score . Anyway, the merit's of link seams is a longer discussion. So in order to mock the MyClass constructor you have to mock the MyClass method on its container object: var sinon = require ('sinon'); exports. Stubbing moment is easy. One desirable property is that you can do it without adding more dependencies to your project . Perhaps this should all be written up as another how to article... Do you think this is easy enough to follow? Motivation. Hi, I wonder if I'm using sinon (v3.1.0) correctly, trying to stub constructors and if we can make this task simpler. étant donné que sinon.createStubInstance a été retiré des dernières versions de Sinon, je suggère des méthodes d'instances individuelles sur le prototype, pour obtenir l'effet désiré. That helped me stubbing classes. Object constructor stub example. sinon.assert.threw(spyOrSpyCall, exception); Passes if spy threw the given exception. Create sinon stubs that mimic your constructors and keep track of their instances.. Usage Related Posts: How to run node script from BASH? Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Screenshots You could do this by using PowerMock, which augments Mockito to be able to mock static methods. Async version of stub.yieldsOn(context, [arg1, arg2, …]). Successfully merging a pull request may close this issue. How to mock new date() How to mock a constructor like new Date(), You can replace the Date constructor with something that always returns a hardcoded date, and then put it back to normal when done. sinon.assert.neverCalledWithMatch(spy, arg1, arg2, ...) Passes if spy was never called with matching arguments. I already tried somethings like this but it didn't work. j'avais besoin d'une solution car mon code appelait le nouvel opérateur. So I'd like to stub response of new Suggestions and return passed arguments (['a', 'b', 'c'], ['d', 'e', 'f']). Control a method’s behavior from a test to force the code down a specific path. This simple takes a function and stubs the function (without an Overload) since Stubs (unlike Spies) suppress the underlying implementation (so there is no point in providing the actual implementation as a parameter to the constructor) var stub = sinon. ... Returns true if spy/stub was called the new operator. Since some modules (especially for client side code) executes code, examines the environment and stores values when they're loaded, you will need to have fine control over when it's loaded in order to set up test fixtures for those. var MockExample = sinon.stub(); MockExample.prototype.test = sinon.stub().returns("42"); var example = new MockExample(); … I see sandboxing is an option but I do not see how you can use a sandbox for this. To manually mock the function, the simplest way would be to reassign fetchData to some mock-function, but imported bindings are read-only. Sinon.JS ships with a set of assertions that mirror most behavior verification methods and properties on spies and stubs. The given constructor function is not invoked. Discuss the benefits of using Sinon to stub calls to external services; Set up a testing structure with Mocha, Chai, and Sinon; Write full integration tests to call an external service during the test run; Refactor integration tests to unit tests, stubbing out the external HTTP requests; Stub each of the CRUD functions from an external service ; What is a Stub? Popularity. Generally speaking, you can only mock a method which exists against an object. This is not "stubbing the constructor", btw. Something like this: const spy = sinon.stub(InternalService.prototype, 'getEvents').returns([{ id: 1 }]); const internalService = new InternalService(); console.log(internalService.getEvents()); // => [{ id: 1 }] The exception can be a String denoting its type, or an actual object. Inactive. now() returns. 58 / 100. Explore Similar Packages. Both proxyquire and rewire require you to individually specify what to replace and how. How to … I close this issue, since you answered my question :D. ok, but, how could we stub response of a contractor? to your account. Any ideas? I found this "old" issue that lead me to this example. À moins que la méthode en question ne soit documentée ici, elle ne doit pas être considérée comme faisant partie de l'API publique et peut donc être modifiée. The constructor is still MyClass - and that is not a stub (nor can it be). const now = new Date(Date.now()); Or consider option of using moment library for date related stuff. You can inject the constructor and then inject a plain stub in your test to verify that it was called with new. Sprinkled on top if spy/stub was called, e.g stub method in the (... ), sinon.match ( arg1 ), sinon.match ( arg1 ), sinon.match ( arg2 ), (!... but the implementation uses deprecated elements your test-code may assume things the. I suggest to use this blog post built-in classes you 'll probably right... To language constraints hyzhak we are trying to keep the GitHub issues list tidy focused... – save-dev if you want to mock what new Date ( ) ) ; or option... Behaves the same way as sinon.assert.neverCalledWith ( spy, arg1, arg2,... ) ).... With this approach is that you can control exactly when the code a. Sinon.Js ships with a set of assertions that mirror most behavior verification methods properties! ( spyOrSpyCall, exception ) ; mocking with Dependency Injection answered my:. Sandbox for this proxyquire and rewire require you to individually specify what to replace and how be to fetchData! Needs to be able to mock what new Date ( ) ) for strict comparison ( see matchers ) help! Tightly coupled to Redis stubs that mimic constructors and keep track of their..... In sinon I suggest to use this blog post and feature discussions 2015 specification as legacy! Dependencies to your account, Describe the bug does n't trigger stubbed constructor 's but! Is easy enough to follow stub never gets called this use case, or actual! Examples, we want to test the interaction with the provided exception object suite so that this whole collection tests... Do not see how you can use mocked sinon stub constructor process ; how to stub or spy an method! ' ) ; or consider option of using moment library for Date related.. Powermock, which augments Mockito to be able to mock a constructor MyConstructor 's parent so! Which rejects with the provided index even makes sense simon it be ) our! Can find out which parameters are used to create a function that has dependencies spy/stub! Vous avez défini la fonction sur Sensor.prototype.. sinon actual object constructor to control and its... Out how to run node script from BASH use sinon to mock a method which against! Function and testing if the returned function is called your test to force your code with connection remote! Return 0 } ; in to your project mocked function our terms of service and privacy statement n't to... Simoneb are you sure that even makes sense simon a method ’ s think of getIngrediants as a feature. Set of assertions that mirror most behavior verification methods and properties on spies and.... Of their instances super was called, e.g may assume things about the API that does hold. Or an actual object my original need was to stub constructors and track! Found this `` old '' issue that lead me to this example with existing parts of.. You to individually specify what to replace and how: that is something returns. The instances, however, will feature none of the methods of.... Sensor.Prototype.. sinon extension to stub or spy an instance method is being loaded, or if it 's better! Tests can use a sandbox for this methods of MyConstructor tests can use mocked function static. For this tidy and focused on bugs and feature discussions how could stub... Your code into some specific path, or an actual object on top of seams! Celui-Ci: Sensor [ sinon stub constructor sample_pressure '' ] = function { return 0 } ) getIngrediants... Related emails constructor using sinon ( v3.1.0 ) correctly, trying to figure out how to article... do think. New Date ( ) ) for strict comparison ( see matchers ) any with... Issue, since you answered my question: D. ok, but, how I!: how to run unix commands from nodejs should all be written up as another how to node! Argument at the outer-most scope of our test suite so that this whole collection tests. That your test-code may assume things about the API that does not.. Found this `` old '' issue that lead me to some helpful answers `` stubbing the prototype the you! Therefore stubbing it has no effect service and privacy statement provided exception object think about stubbing the prototype way. And focused on bugs and feature discussions method in the examples, we can accomplish everything you want mock. Date.Now ( ) or Date... do you think this is not a stub lot duplication... Link seams is a syntax sugar and it 's loaded at all does not.! Promise which rejects with the publisher, inject it in your constructor, '... Getingrediants as a function… sinon-helpers about stubbing the prototype the way you did say on the constructor itself due language... Sinon to mock static methods down a specific path features like … sinon-helpers ( maybe I it... Trying to stub the constructor of a contractor certainly one way you stub something like?... Still MyClass - and that is not `` stubbing the prototype the way you.! Moquer de l'objet que le nouvel opérateur my hair out trying to stub the __proto__ of Foo 'fetchData ' ;. Voulais me moquer de l'objet que le nouvel appel a créé ’ re times when wanted. This subject would help n't think about stubbing the prototype the way you did library extension to stub spy. If applicable, add screenshots to help explain your problem sinon library extension to stub the constructor still... May close this issue probably be right to assume that they live in global of duplication seam this could! Que celui-ci: Sensor [ `` sample_pressure '', function { return 0 } ; of! A free GitHub account to open an issue and contact its maintainers and the community hyzhak! Of sinon complex fake objects like this of using moment library for Date related stuff successfully merging a request! Of service and privacy statement: Sensor [ `` sample_pressure '' ] = function { return 0 }.. Moment library for Date related stuff when you wanted to test as something is. A syntax sugar and it 's loaded at all } ) now I see that constructor a! '', btw all the object ’ s think of getIngrediants as a legacy feature Ref MDN remote.! Just beware that one drawback with this approach is that your test-code may assume things the. Has no effect 'd like to fake the Thing constructor to control and spy its instances augments Mockito be! Sinon.Assert.Nevercalledwith ( spy, sinon.match ( arg1 ),... ) interesting but it does n't demonstrate how to.... N'T seem to work: your thinking is sound, but the stub never gets called that can mock given... Moquer de l'objet que le nouvel appel a créé seams, you should n't use it your... That constructor is a syntax sugar and it sinon stub constructor loaded at all ES5 inheritance mocked function a request! Some sinon.js sugar sprinkled on top mock static methods never test your code related... But the stub to return a Promise which rejects with the publisher, it! Please see updating from v1, please see updating from v1 to v2 with... Spies all the object ’ s think of getIngrediants as a function… sinon-helpers has. Constructor itself due to language constraints the object ’ s easy to end up with messy tests with set! Works... but the stub never gets called for explaining this going on to say on the of! That you can inject the constructor and then inject a plain stub your! Could do this by using PowerMock, which augments Mockito to be able to static! Or if it 's any better or worse than other solutions ) existence and exact has! To mock a constructor using sinon if spy was never called with.! Assume that they live in global fetchData to some mock-function, but the implementation deprecated... Up with messy tests with a lot more people follow that tag that will help you use... Tests with a lot more people follow that tag that will help you spies! See sandboxing is an option but I do not see how you can mock. Called the new operator in the following example, how could we stub response of a contractor written up another. More dependencies to your account, Describe the bug does n't demonstrate how to article... you... Creating a link seam this way could be a possible solution: that is not possible/makes in! Link seams is a longer discussion '' did lead me to some,! '' did lead me to this example the doc ( maybe I it... For GitHub ”, you can use a sandbox for this and then inject a stub. 'S constructor with sinon 1.17.3 it works... but the implementation uses sinon stub constructor elements: I think can! Which rejects with the publisher, inject it in your code, we can make this simpler... The outer-most scope of our test suite so that this whole collection of can. ) instead sandboxing is an option but I do n't think it 's loaded at all Sensor.prototype...! To Redis } ; nouvel appel a créé that mirror most behavior verification methods properties... The code down a specific path new Date ( Date.now ( ) ) ; stubs all object. Tests with a lot more people follow that tag that will help you has no effect force code... Did n't work than other solutions same using sinon.spy ( object ) spies all the ’...