How do you stub a promise in Sinon?

How do you stub a promise in Sinon?

Very simple, one just have to stub the function that will return the Promise, use the function returnsPromise. After that, you just have to the if the Promise will resolve and reject. Oh yeah! And if you’re using karma to run your tests there’s even a plugin for that karma-sinon-stub-promise.

How do I use stub function in Sinon?

How To Stub A Function Using Sinon

1. module.
2. // app.js file const lib = require(‘./lib’) console.
3. # run the app.js file node app.js.
4. # installing sinon npm install –save-dev sinon.

How do I restore my Sinon stub?

var stub = sinon. The original function can be restored by calling object. method. restore(); (or stub. restore(); ).

How do I stub an object in Sinon?

Stubbing an entire complex object In a situation like this, the easiest way to stub this is to just create a new object which you can then pass in as a parameter in your test: var elStub = { id: ‘foo’, children: [], setAttribute: sinon.

What is Sinon restore?

restore() just restores the behavior of the stubbed functionality but it doesn’t reset the state of the stubs. You’ll have to either wrap your tests with sinon.test and use this.stub or individually call reset() on the stubs.

What is Sinon chai?

Sinon–Chai provides a set of custom assertions for using the Sinon. JS spy, stub, and mocking framework with the Chai assertion library. You get all the benefits of Chai with all the powerful tools of Sinon.

What does stub restore do?

reset() and restore() reset() . Another is stub. restore() , which is used to restore the original functionality to the stubbed function. You want your tests to be independent of each other and adding this to stubbed methods will help guarantee that.

What is Sinon spy?

sinon.spy(object, “property”, [“get”, “set”]) creates spies that wrap the getters and setters for object.property . The spies will behave exactly like the original getters and setters, but you will have access to data about all calls. Example: var object = { get test() { return this.

What is Sandbox Sinon?

JS. Sandboxes simplify working with fakes that need to be restored and/or verified. If you’re using fake timers, fake XHR, or you are stubbing/spying on globally accessible properties you should use a sandbox to ease cleanup.

What is Sinon in testing?

Sinon JS is a popular JavaScript library that lets you replace complicated parts of your code that are hard to test for “placeholders,” so you can keep your unit tests fast and deterministic, as they should be.

How do you mock in Sinon?

The rule of thumb is: if you wouldn’t add an assertion for some specific call, don’t mock it. Use a stub instead. In general you should have no more than one mock (possibly with several expectations) in a single test. Expectations implement both the spies and stubs APIs.

How to resolve a promise in Sinon?

At current sinon version v2.3.1, you can use stub.resolves (value) and stub.rejects (value) function You just have to resolve the promise before you call the search function. This way your stub will return a resolved promise and then will be called immediately.

How to stub tests using Sinon?

Recently I’ve found a small and nice package to help to stub tests using Sinon, and the library is sinon-stub-promise. So, imagine you have a code like the following: A test for this code would be something like: Very simple, one just have to stub the function that will return the Promise, use the function returnsPromise.

How to return a value from a Sinon function?

At current sinon version v2.3.1, you can use stub.resolves (value) and stub.rejects (value) function For example, you can stub myClass.myFunction with following code sinon.stub (myClass, ‘myFunction’).resolves (‘the value you want to return’);

How to return a promise from a test?

Very simple, one just have to stub the function that will return the Promise, use the function returnsPromise. After that, you just have to the if the Promise will resolve and reject. Oh yeah! And if you’re using karma to run your tests there’s even a plugin for that karma-sinon-stub-promise.