Coverage testing

Playing walks one route at a time. Coverage testing walks thousands: it runs your story through automatically, picking a random option at each choice, and counts how often every beat is reached. It’s the fast way to answer “does anything ever actually get here?” and to catch dead content before a player does.

Running the test

Review ▸ Run Coverage Test… opens a window that stays open while you edit, so you can act on what it finds. Up top: Runs, Max steps, Seed (the same seed replays the same run, for repeatable checks), and a Start scene. Press Run test for a per-scene table of every line, narration, and game event beat with its reached % and hit count.

The story needs a start point for the test (and for Play ▸ Play from Start); if you haven’t set one, you’ll be asked to pick a scene, saved to Project Settings ▸ General ▸ Start.

Click any row to jump the editor straight to that beat. The window can pin itself on top (on by default) and keeps your last results for the session.

What it flags

Beats that never come up are flagged two ways:

• ‼ (dead): nothing ever reaches it. Usually a branch that can’t be taken, or a condition that’s never true.
• ? (needs input): it turns on a value your game owns (@world.*) that nothing in the story sets, so the test can’t reach it on its own. The row reads gated on @x; click that name to see everywhere @x is used. Add a driver and the test can reach it.

Choices that ran dry

If a choice ever ends up with nothing the player can take and no fallback, it silently steps past itself at runtime rather than dead-ending the game. That is easy to author by accident, so the test also flags any choice it actually saw run dry, with the run count and a click-through to the choice. Give such a choice a fallback option, or one unconditional option, to guarantee the player a way through. (Patterpad also warns about this statically, in the Problems panel.)

World Properties and input drivers

Some branches turn on values your game owns rather than the story, written as @world.name and declared up front in Project Settings ▸ World Properties. Declaring them is part of setting up the project; what matters here is that a declared @world value gives the test a default to fall back on, and a place to hang a driver.

Input drivers

Since your game sets these while it runs, the coverage test can’t know them, so a branch that turns on @world.alarm reads as needs input. To exercise it, add a coverage driver in the same tab: name a @world value and give the test a pool to draw from (once at the start, or re-rolled at each choice). Propose from story fills these in for you by reading your conditions (@world.threat >= 50 becomes 49, 50, 51; a pick-list becomes its options), ready for you to tweak.

On the command line

The same coverage test runs headlessly as patter coverage (with --fail-on-gap for CI): see the CLI page.