Extending the fault classification hierarchy for software with relational operators

Testing is a simple and direct way for making software more reliable. Many specification-based software testing mechanisms utilize test points generated based on fault hierarchies, classes of which are categorized by common faults frequently introduced during software implementation. The testing method is effective to identify Boolean faults but has a severe drawback, which is not applicable to testing software with relational operators such as “>” or “!=”. This paper carefully investigates the characteristic of relational operator faults and proposes a unique way to find relational operator reference faults in software. Its feasibility is also shown by applying the proposed method to a HVAC (Heating/Ventilating/Air-Conditioning) system of commercial vehicle. Key-Words: Specification-based test, Boolean fault, relational operator reference fault. Fault classes hierarchy