Mutating database queries

A set of mutation operators for SQL queries that retrieve information from a database is developed and tested against a set of queries drawn from the NIST SQL Conformance Test Suite. The mutation operators cover a wide spectrum of SQL features, including the handling of null values. Additional experiments are performed to explore whether the cost of executing mutants can be reduced using selective mutation or the test suite size can be reduced by using an appropriate ordering of the mutants. The SQL mutation approach can be helpful in assessing the adequacy of database test cases and their development, and as a tool for systematically injecting faults in order to compare different database testing technique

Comparison of Fault Classes in Specification-Based Testing

Our results extending Kuhn’s fault class hierarchy provide a justification for the focus of fault-based testing strategies on detecting particular faults and ignoring others. We develop a novel analytical technique which allows us to elegantly prove that the hierarchy applies to arbitrary expressions, not just those in disjunctive normal form. We also use the technique to extend the hierarchy to a wider range of fault classes. To demonstrate broad applicability, we compare faults in practical situations and analyze previous results. In particular, using our technique, we show that the basic meaningful impact strategy of Weyuker et al. tests for stuck-at faults, not just variable negation faults. Key words: Fault-based testing; Specification-based testing; Kuhn’s hierarchy; Fault classe