Requirements are often reported as not suitable for testing, because they are, for instance, incomplete. We argue in this paper for early steps in requirements engineering to ensure the testability of requirements in the context of product families. This paper describes the early derivation of test scenarios from use cases represented as activity diagrams. Use cases are often supplemented with activity diagrams if the control structure of the use case includes loops or branches. The use of activity diagrams allows defining a coverage criterion to ensure a particular degree of completeness of the test scenarios. The approach described in this paper is intended for use cases at the domain engineering level. It is discussed how variability in these use cases can be captured in activity diagrams, and, most important, how to address variability while deriving test scenarios so that a particular degree of completeness is reached. For this purpose, we adapt the existing branch coverage criterion to the needs of product families and provide an operational procedure that helps in deriving a set of test scenarios that fulfills our extended coverage criterion. Eventually, the derivation of test scenarios gives an early feedback to the requirements engineer when performed from the tester?s perspective. This increases the requirements quality.