SinonJS provides stand-alone test spies, stubs and mocks. It is a library that we can use to create object mocks for unit testing.
Spies − Fake functions that we can use to track executions.
Stubs −Functions replacements from which we can return whatever we want or have our functions work in a way that suites us to be able to test multiple scenarios.
Mocks −Fake methods
All these objects help in unit testing our code.