15. The system of claim 14 , wherein the natural language processing system is implemented at least in part by a knowledge base, the knowledge base including a plurality of concept-based components that each associate a pattern of concepts with a response.
15. The system of claim 14 , wherein the natural language processing system is implemented at least in part by a knowledge base, the knowledge base including a plurality of concept-based components that each associate a pattern of concepts with a response. 16. The system of claim 15 , wherein the particular result that is associated with the test user input comprises a concept-based component of the plurality of concept-based components, and the operations further comprise: determining that the processing does not satisfy the one or more criteria based at least in part on a concept-based component that is identified from the processing not matching the concept-based component that is associated with the test user input.