# An Experimental Evaluation of Path-Based Product Line Integration Testing and Test Coverage Metrics
###### Abstract  
Product line testing is significant because any faults in a product line platform can lead to widespread impacts on multiple products configured from that platform within a product line. Due to the shared platform, certain testing can be repeatedly performed across different products, leading to unnecessary costs. To enhance quality and reduce costs in product line testing, it is essential to minimize redundant testing of the products in a product line. Because test coverage provides a way to explicitly state the extent to which a software item has been tested, having a clear understanding of test coverage helps avoid unnecessary repetition of tests and ensures that the testing efforts are focused on areas that require attention, ultimately leading to more efficient and effective product line testing. It is necessary to define appropriate test coverage metrics of product line testing that enable testers to identify redundancies in their testing efforts. Path-based integration testing has been proven to be an effective approach to product line integration testing. This paper defines coverage metrics for path-based product line integration testing and demonstrates their effectiveness in preventing redundant testing between platform testing and testing for individual products, while also effectively detecting faults. The experiment results highlight the coverage metrics' effectiveness in avoiding redundant testing, reducing costs, and covering interfacing across different modules.  
software product line testing; software product line integration testing; path-based integration testing; test coverage metrics; test coverage measurement +
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line [4; 5; 6]. Thus, it is essential to measure test coverage using the test coverage metrics of SPLT to find out the extent of redundancy.  
However, in SPLT, there has been limited discussion regarding SPL integration testing and test coverage metrics, except SPL system testing, particularly when compared to the extensive discussion about them in single software testing [7]. Recognizing this gap, [PERSON] [8] proposed basic concepts for path-based integration testing and coverage metrics applicable to SPL integration testing. This paper builds upon and refines these concepts, offering comprehensive path-based integration testing and test coverage metrics to address redundant testing issues by providing clear test coverage measurement for both platform testing and product testing. Furthermore, this paper confirms the effectiveness of path-based SPL integration testing and test coverage metrics with respect to test redundancy, test costs, and fault detection.  
This paper is structured as follows: Related work is discussed in Section 2. Section 3 presents the path-based SPL integration testing method, along with the associated test coverage metrics and the essential concepts necessary to extend the MM-path-based integration testing method from a single software system to SPLT. Section 4 defines cost and benefit functions used to assess the effectiveness of the proposed method. Section 5 describes experimental evaluation results, including two experiments that provide answers to research questions. Section 6 covers discussions of the experimental evaluation of path-based SPL integration testing, while Section 7 addresses threats to validity. Section 8 concludes this paper.