Question

What is the difference between a mock and a stub, they both seem very similar to me?

It would be nice if someone could give a real world example of when to use which, or are they interchangeable but there is a best-practise like when to use a mock or a stub?

Answer 1

This is the reference in most articles, pretty generic and clear explanation:

http://martinfowler.com/articles/mocksArentStubs.html

In a nutshell:

Stubs provide canned answers to calls
made during the test, usually not
responding at all to anything outside
what’s programmed in for the test.
Stubs may also record information
about calls, such as an email gateway
stub that remembers the messages it
‘sent’, or maybe only how many
messages it ‘sent’.

And

Mocks are objects pre-programmed with
expectations which form a
specification of the calls they are
expected to receive.