Impact of Test Design Technique Knowledge on Test Driven Development: A Controlled Experiment

Agile development approaches are increasingly being followed and favored by the industry. Test Driven Development (TDD) is a key agile practice and recent research results suggest that the successful adoption of TDD depends on different limiting factors, one of them being insufficient developer testing skills. The goal of this paper is to investigate if developers who are educated on general testing knowledge will be able to utilize TDD more effectively. We conducted a controlled experiment with master students during the course on Software Verification & Validation (V&V) where source code and test cases created by each participant during the labs as well as their answers on a survey questionnaire were collected and analyzed. Descriptive statistics indicate improvements in statement coverage. However, no statistically significant differences could be established between the preand post-course groups of students. By qualitative analysis of students’ tests, we noticed a lack of test cases for non-stated requirements (“negative”tests) resulting in a non-detection of bugs. Students did show preference towards TDD in surveys. Although further research is required to fully establish this, we believe that identifying specific testing knowledge which is complementary to the testing skills of a new TDD developer would enable developers to perform their tasks in a more efficient manner.