The environment reacts

Reactive Events & Fault Recovery

Model errors, asynchronous interrupts, firmware handshakes, recovery paths, and deliberately hostile conditions as first-class scenarios.

The environment reactsThe shared verification responsibilities

01TRIGGERInject a fault or observe an asynchronous event
02DETECTPredict the exact exception or service obligation
03CONTAINPrevent corrupted state from becoming architectural
04RECOVERClear, acknowledge, retry, or restore useful work

Negative testing · IRQ Testing · Deadlock Detection · Firmware DV

Build reactive stimulus that pre-empts normal traffic, predicts expected exceptions, observes side effects, and proves recovery rather than merely detecting corruption.

The case library

Start with a failure.

Pick a mechanism. Open an experiment.

4 case studies

Negative testingReject the packet. Reuse its ID.

Failure to investigateEvents & recovery

Negative Testing and Exception Scoreboarding

An expected CRC or ECC rejection appears as a false data mismatch.

Enter the lab ↗

InterruptsThe tenth event—or the timeout?

Failure to investigateEvents & recovery

IRQ Subsystem Verification

An event is dropped and the expected IRQ never arrives.

Enter the lab ↗

Deadlock & livelockNo progress. What does that prove?

Failure to investigateEvents & recovery

Deadlock, Livelock & Credit Watchdogs

Items remain in flight while the completion counter does not change for the watchdog window.

Enter the lab ↗

Firmware ↔ hardwareWhat arrives at the timeout?

Failure to investigateEvents & recovery

Firmware & Hardware-Software Interface Verification

A firmware-equivalent sequence no longer matches the current software driver or header definitions.

Enter the lab ↗

Practice with real interview promptsPractice this verification family in the question bank

Continue the evidence chain

Connect cases to system strategy.

Move from focused failure modes to a complete plan, executable architecture, coverage model, regression system, and sign-off argument.