Techniques are described for checking whether system properties meet the requirements of a software application. These checks are performed by executing validation checks associated with the application, which often include validation checks associated with other applications with which the application integrates. A validation engine takes several inputs that drive the validation checking that is performed in conjunction with an operation associated with the application. In one aspect, a modular approach to integrating an application's validation checks with other applications' validation checks is provided via a properties file that contains metadata for all the files in an application's validation module. In another aspect, conditional logic is introduced into a knowledge source so that similar logic does not need to be in the validation test code. In another aspect, the validation test identifiers input is extended to support multiple modes of operations.