A software product testing system may include a knowledge base with a data set that includes multiple possible actions and, for each action, language-specific format rules for inputs and outputs associated with the action. The software product testing system may include a test case generator that selects a test case in a target language for a software product. The test case may include a selected action to be taken by a software product, an input to prompt the action, and an expected output that corresponds to the selected action and the input. The expected output has a format corresponding to a language-specific format rule of the target language. The software product testing system may also include a test verifier that determines whether an output generated by application of the test case to the software product matches the expected output.