Mock4JS: stubs() versus expects()

In the previous examples, I have used expects() like this:

mockObject.expects(once()).someMethod().will(returnValue("result"))

This says that the mock object expects exactly one call to someMethod(). If there is not exactly one call, the test will fail. If for a particular test case it is not interesting to make this assertion, then you should use stubs() instead:

mockObject.stubs().someMethod().will(returnValue("result"))

In this case, the mock object does not care how many times someMethod() is called, but each time it does get called it will return "result"

Use of stubs() for uninteresting/unimportant method invocations is recommended because it helps keep the test focussed on the specific test case intent. Additionally, any changes in the real object's behaviour will break less tests.