Do Null-Type Mutation Operators Help Prevent Null-Type Faults?
This addresses a specific issue for Java developers by providing incremental improvements to mutation testing for preventing null-type faults.
The authors tackled the problem of null-type faults in Java programs by designing four new mutation operators that explicitly model these faults, demonstrating their capability to reveal missing tests and analyzing their practical utility in 15 open-source projects.
The null-type is a major source of faults in Java programs, and its overuse has a severe impact on software maintenance. Unfortunately traditional mutation testing operators do not cover null-type faults by default, hence cannot be used as a preventive measure. We address this problem by designing four new mutation operators which model null-type faults explicitly. We show how these mutation operators are capable of revealing the missing tests, and we demonstrate that these mutation operators are useful in practice. For the latter, we analyze the test suites of 15 open-source projects to describe the trade-offs related to the adoption of these operators to strengthen the test suite.