A computer system verifies functional test patterns for diagnostics, characterization and manufacture testing. The system generates, by a system designer, verification sequences including initial trace traces selected from a verification sequence data to test system functional design. The system includes a trace module, an emulated pattern generator module, and a test pattern verification and debug module. The trace module adds custom information to the traces to generate modified traces and the system executes the verification sequences against a device to generate traces. The trace module further processes the modified traces by parsing the captured modified traces. The system verifies data integrity and summarizes statistics of the captured traces. The emulated pattern generator module generates emulated test patterns, which are based on the output of the trace module and have independent format streams compatible with a device test port. The test pattern verification and debug module verifies the emulated test patterns.