A typing test where you're breaking in, and every keystroke makes a sound, race the words while the guard's back is turned, then freeze when it listens.
Type the words on screen to make progress, but each keystroke is noise. A guard patrols on a rhythm: while it's looking away you can hammer the keys and burst through text, but when it turns to listen you have to go silent. Type at the wrong moment and your noise is heard, three strikes and you're caught.
Typing words on screen as the mechanic rather than the interface is the typing game, whose best-known example is The Typing of the Dead — Sega's 1999 arcade machine that took House of the Dead 2 and replaced the light gun with a keyboard.
The original idea is to treat keystrokes as noise. A guard patrols on a rhythm; while it is looking away you can hammer the keys, and when it turns to listen you must go silent.
That makes typing fast actively dangerous, which no typing game does. Crossed with the stealth genre's patrol-and-hide loop, speed stops being the score and becomes a resource you spend in windows — so the skill is knowing when to stop, which is the opposite of what a typing test measures.
Quietype is an original free browser game that fuses the typing-speed test with stealth mechanics, turning the act of typing into a noise you have to time around a patrolling guard.