The uncomfortable question of this project: how do you review a visual change in a shell that runs on a 386 from 1992? You cannot scroll a pixel diff on a CRT, and real mode has no screenshot button. Castalia 92's answer is not to reimplement the drawing on the host: it is to boot the real binary and photograph it.
The trick: CI stands up a 386
The smoke pipeline (`ci/smoke.sh`) takes the .EXE Open Watcom has just built, boots it in DOSBox under a virtual X server (Xvfb) and captures the screen with ImageMagick. There is no second implementation of the renderer that could drift from the first: what comes out in the image is exactly what the 386 would paint, because it is the same executable that ships.
What comes free with it
With that in place CI does not only check that the project compiles: it checks that it boots. A change that breaks mode 13h, the window Z-order or the default theme stops being a bug report from a tester with a modem — it is an image attached to the build. And the other gates run in the same pipeline: the 57 KB DGROUP memory watermark, the C89 lint, the build-consistency check.
If it is in a screenshot, it is because the binary drew it. Zero mockups.
D. ABELLÁN · FOUNDER · PRINCETON, IL · 2026.06.05