sinon spy constructor

The returned spy is the function object which replaced the original method. // Check that spy was called with `new` operator and uses constructor calledWithNew // Check that spy threw an exception at least once threw threw ("string") threw ... Sinon Spy Archi - Wrap old fn with new fn and use new fn in place of old one WITHOUT SPY - MyFn —-> Orig Fn; It’s possible to assert on a dedicated spy call: sinon.assert.threw(spy.thirdCall, exception);. The function sinon.spy returns a Spy object, which can be called like a function, but also contains properties with information on any calls made to it. spy (); myAsyncFunction (spy) ... Constructor functions and ES6 classes are also supported. Spying on a constructor in javascript with sinon (2) Considering your constructor is bound to 'window' which means that if you open developer console on your browser, you should be able to intantiate an object by using the related function/constructor as such: Something like this: const spy = sinon.stub(InternalService.prototype, 'getEvents').returns([{ id: 1 }]); const internalService = new InternalService(); console.log(internalService.getEvents()); // => [{ id: 1 }] I'm using sinon-chai so the syntax is valid, but both tests fail. This post intends to show how to mock a class in JavaScript for the purpose of Unit Testing. On Thursday, February 23, 2017 at 2:38:03 AM UTC+9, Christian Johansen wrote: Private properties are implementation details. @fatso83 Sure, I've already read related issues prior to posting this one.. Spy call, Spy call - Sinon.JS. var c = new MyClass() var spy = sinon.spy(c, "myFunc"); Clearly the spy is not in place when the constructor is called. In Safari or PhantomJs it fails with TypeError: Attempted to wrap object property WebSocket as function spy === object.method. 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) Creates a spy for object.method and replaces the original method with the spy. Sinon mock javascript class. Any kind of help wou this answer edited Aug 15 '14 at 20:43 Aurélien Gasser ♦ 1,033 8 17 answered Jan 28 '13 at 21:12 ppoliani 2,299 1 15 47 Thanks ppoliani. I have changed my code to inject the dependency into the constructor. However, you create a new Paper object with an Origami property in your test. Unless the method in question is documented here, it should not be considered part of the public API, and thus is subject to change. A spy call is an object representation of an invididual call to a spied function, which could be This is actually pretty bad answer because OP obviously does not want to use sinon's spy. The thing that differs ES6 classes from ES5 constructor functions is a safeguard that prevents them from being used like var bar = Object.create(Bar.prototype); Bar.call(bar).. sinon.assert.alwaysThrew(spy, exception); Like above, only required for all calls to the spy. Another approach to isolating dependencies is to initialize them in the constructor of the class. When doing so, the original function will behave just as normal (including when used as a constructor) but you will have access to data about all calls. sinon.spy can also spy on existing functions. It sounds like what I'd like to do is impossible, but for reasons that have nothing to do with ES6. require resolves paths before looking in its cache, so it should not matter that the paths are different. For example, a spy can tell us how many times a function was called, what arguments each call had, what values were returned, what errors were thrown, etc. Stub. Test constructor calling a method with Sinon I'd like to ensure that the constructor is calling a method when instantiated with Sinon, however, I can't seem to get this to work, as I believe the sinon is not watching the correct instantiation: To solve this problem you can move the method myFunc in the prototype of the MyClass object and then spy the methods in the prototype. and.returnValue() A spy can be made to return a preset/fixed value (without the need for calling the actual methods using and.callThrough()). Instead of calling sinon.stub or sinon.spy, sandbox.stub and sandbox.spy are used instead. spy (exports, 'MyClass'); var MyClass = exports. How to properly mock ES6 classes with sinon, Sinon allows you to easily stub individual instance methods of objects. This discrepancy occurs because Sinon wraps exports.MyClass with its own mechanism, which means that the MyClass local variable which points directly to the constructor remains unaffected. A test spy is an object that records its interaction with other objects throughout the code base. Hi, I wonder if I'm using sinon (v3.1.0) correctly, trying to stub constructors and if we can make this task simpler. After stub a es6 class, I want to mock the return value when instantiating it. In Chrome it fails with Uncaught TypeError: Failed to construct 'WebSocket': Please use the 'new' operator, this DOM object constructor cannot be called as a function. What I'm trying to … As such, a spy is a good choice whenever the goal of a test is to verify something happened. MyClass = function {this. But I could not understand where I should use sinon.spy() to check whether this function has called or not. For example: Hence, when you spy on Paper, 'Origami', it is the property Origami of the Paper object you created locally in your test file which is replaced with a spy. It does not spy on another function. Standalone test spies, stubs and mocks for JavaScript. So, sinon.spy(s,'nextSeason'); in Sinon is equivalent to spyOn(s,'nextSeason').and.callThrough(); in Jasmine. In Sinon, a spy calls through the method it is spying on. Utils API sinon.createStubInstance(constructor); Creates a new object with the given function as the protoype and stubs all implemented functions. var spy = sinon. var foo = function(arg) { }; var Combined with Sinon’s assertions, we can check many different results by using a simple spy. a = 1;}; var spy = sinon. class B { constructor() {} doOther(number) { return new var mock = sinon.mock(obj); Creates a mock for the provided object. OP wants to SPY ON the standalone function. Sinon spy() creates function. 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All implemented functions calling object.method.restore ( ), created for publish property it sounds what.

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