1. A method comprising: generating a virtualized Application Programming Interface (API) implementation that simulates an API based upon narrative API documentation that comprises sentences that describe the API, wherein the generating is performed by processor circuitry, wherein generating the virtualized API implementation based upon narrative API documentation that comprises sentences that describe the API comprises: generating programming statements for the virtualized API implementation based upon parsing the narrative API documentation that comprises sentences that describe the API; and generating the virtualized API implementation based upon the programming statements for the virtualized API implementation, wherein generating programming statements for the virtualized API implementation based upon parsing the narrative API documentation that comprises sentences that describe the API comprises parsing the narrative API documentation using a domain-specific ontology for the API, wherein parsing the narrative API documentation using the domain-specific ontology for the API comprises: identifying parameters of the API from the narrative API documentation; and identifying normal and abnormal behaviors of the API from the narrative API documentation, wherein the identifying parameters of the API from the narrative API documentation comprises: identifying a type of a parameter; identifying syntactical constraints on a parameter; identifying range constraints on a parameter; identifying invariants of a parameter; identifying transforms of a parameter; and identifying semantic inferences of a parameter, and wherein the method further comprises: converting the parameters of the API and the normal and abnormal behaviors of the API into the programming statements for the virtualized API implementation.