In this demonstration we will show the flow of the Mock Object development process by pair-programming to develop a code example. During the session, we will introduce the declarative jMock API and show how we use it to describe relationships between objects when developing test-first. We will show how this approach helps developers concentrate on real requirements and how it encourages a design in which objects are focused with well-defined responsibilities. We will also show our practices for maintaining the readability of tests written using jUnit with jMock. This work is described in a Practitioner Report at this conference, "Mock Roles, Not Objects".