Pairwise testing, also known as pairwise combinatorial testing, is a software testing technique that involves testing all possible discrete combinations of pairs of input parameters. This method is particularly useful for systems with numerous input variables, where testing all possible combinations (exhaustive testing) is impractical due to time and resource constraints.
Key Concepts of Pairwise Testing
- Combinatorial Testing: Pairwise testing is a subset of combinatorial testing, focusing specifically on testing the interactions between pairs of input variables. The assumption is that most defects are caused by interactions between two variables rather than more complex interactions.
- Coverage: The primary goal is to ensure that all possible pairs of input variables are tested at least once. This provides a balance between thoroughness and efficiency, ensuring that significant combinations are covered without requiring an excessive number of test cases.
- Efficiency: By focusing on pairs rather than all combinations, pairwise testing significantly reduces the number of test cases compared to exhaustive testing. This makes it a practical approach for larger systems with many input variables.
Steps in Pairwise Testing
- Identify Input Parameters: List all input parameters that can affect the behavior of the system. Each parameter can have several possible values.
- Create Value Ranges for Parameters: Define the possible values for each parameter. These could be specific values, ranges, or conditions.
- Generate Test Cases: Use pairwise testing tools or manual methods to generate test cases that cover all possible pairs of values for the parameters. Various algorithms and tools, such as Orthogonal Array Testing and All-Pairs Testing, can be used to generate these test cases efficiently.
- Execute Test Cases: Run the generated test cases on the system and observe the outcomes.
- Analyze Results: Review the test results to identify defects or unexpected behavior.