Modern integrated circuits contain far more internal states and physical nodes than can be directly controlled or observed from package pins. Effective verification and manufacturing test therefore depend on structured methods for generating stimulus, observing responses, detecting physical faults, and diagnosing silicon failures. Functional verification uses golden models, testbenches, directed and random vectors, regression testing, version control, and bug tracking to establish repeatable evidence that RTL and implementation behavior remain correct throughout development. Post-silicon testing introduces physical effects that are absent or simplified during logical verification. Laboratory bring-up requires controlled power, clocking, register access, test fixtures, and systematic debug procedures. Internal probe points, electrical and optical probing, thermal analysis, voltage-frequency-temperature characterization, and shmoo testing help isolate manufacturing, functional, and electrical failures. Fault models such as stuck-at, open, short, and delay faults provide practical abstractions for manufacturing defects, while fault simulation measures whether test patterns can activat...