Evaluation of Modified Condition/Decision Coverage in Testing a Web Server

Modified Condition/Decision Coverage (MC/DC) is a structural coverage criterion widely used in testing aviation software. Aviation software has a high level of state-based behavior, typically implemented with complex Boolean expressions. MC/DC was developed to provide the benefits of exhaustive testing of the Boolean expressions, without the overhead. Web servers are also state-based systems, and the purpose of this research is to determine whether the benefits of MC/DC also apply to these systems. In this paper, a unit-testing case-study on a typical web server Culture Object Management Web Server (COMWS) was performed to evaluate the effectiveness of MC/DC in this context. For each method in COMWS, Black-Box testing was carried out first, followed by MC/DC testing. The Black-Box testing was used as a control group for MC/DC testing. The comparison focuses on three criteria: Testing Cost, Faults Found and Program Coverage. Based on the experimental results and comparative evaluation, two main conclusions were obtained: MC/DC is an additional effective testing technique to complement Black-Box testing for testing web servers, and it provides extra test capability where some of the variables used in Boolean expression are not directly derived from the input parameters