A first computer receives a first and a second test sample. The first computer executes the first and second test sample. The first computer determines that the value exposed by a first parameter in the second test sample is different from the value exposed by the first parameter in first test sample. The first computer creates a first value driven equivalence class. The first computer determines the value exposed by the second parameter in the second test sample is different from the value exposed by the second parameter in the first test sample and the value exposed by the second parameter in the second test sample is equivalent to the value exposed by the first parameter in the second test sample. The first computer adds the second parameter to the first value driven equivalence class and creates a generalized test case, including at least the first value driven equivalence class.