The development team at your company is ready to test a new application. It has been user-tested and subjected to stringent code review, static analysis, and dynamic analysis. It passes all tests and has been approved to be implemented. However, when the software is implemented, other applications cannot communicate securely with it, and sometimes it fails to negotiate a secure encryption method, instead falling back to an older insecure method. Which of the following types of tests would have discovered this issue?