When creating test cases for software, a common approach is to create tests that exercise requirements. Determining the adequacy of test cases, however, is generally done through inspection or indirectly by measuring structural coverage of an executable artifact (such as source code or a software model). We present ReqsCov, a tool to directly measure requirements coverage provided by test cases. ReqsCov allows users to measure Linear Temporal Logic requirements coverage using three increasingly rigorous requirements coverage metrics: naive coverage, antecedent coverage, and Unique First Cause coverage. By measuring requirements coverage, users are given insight into the quality of test suites beyond what is available when solely using structural coverage metrics over an implementation.

An extension of symbolic transition graphs with assignment is proposed which combines the advantages of both the assignment-before-action and the assignment-after-action approaches: like the former it allows a simple set of rules to be designed for generating finite symbolic graphs from regular value-passing process descriptions; like the later it avoids creating multiple copies in the graph for a recursive process definition. Experiences show that, in most cases, considerable reductions in verification time and space can be achieved using the new approach.