About

Mocking is just replacing or wrapping a function by another function at runtime called a mocking function.

Example:

var request = new HttpRequest(); // the real request
var mockRequest = new HttpMock(request); // the request is wrapped

This function overrule the actual implementation of a function during a test.

It permits then to:

• control the passed parameters
• return a known value or behavior.

Mock function are generally used to simulate a integration test with third party services such as:

• a database
• a http fetch (for rest API and other http services)
• a remote server

Articles Related

Framework

Java:

• mockito
• PowerMock
• https://github.com/powermock/powermock/wiki/Mockito

Javascript:

• https://jestjs.io/docs/en/mock-functions