1. A system comprising: a communication interface configured to receive, from an application prototyping tool: an interactive wireframe representation of a graphical user interface (GUI) of an application, and application behavior data for the application, wherein both the interactive wireframe representation and the application behavior data were captured by the application prototyping tool; a GUI information database configured to store the interactive wireframe representation and the application behavior data after the prototyping tool captures the interactive wireframe representation and the application behavior data; test case generation circuitry in communication with the GUI information database, the test case generation circuitry configured to: extract GUI information from the interactive wireframe representation and the application behavior data stored in the GUI information database, wherein the GUI information comprises Graphical User Interface Components (GUIC), GUIC behavior, and GUIC events for the GUI; determine relationships between the GUICs and the GUIC events as part of the GUI information; determine semantic knowledge from the relationships between the GUICs and the GUIC events, and store the semantic knowledge in a semantic knowledge database; generate a summarized model of the GUI from the GUI information; generate a screen model for selected screens of the GUI using a subset of extracted GUI information in the summarized model, wherein the screen model comprises a behavioral flow for each screen, and the subset of the extracted GUI information for generating the screen model comprises the relationships between the GUICs and structural positioning of the GUICs; generate an application model by combining the screen models for each screen into a unified representation; traverse the application model to generate a test path comprising a sequence of the GUICs and event types for the GUICs; and generate test cases using the sequence of the GUICs and the event types included in the test path and the semantic knowledge stored in the semantic knowledge database for the GUI; and display generation circuitry configured to display the generated test cases in a test case window.