The browser workbench¶
app is a PDF workbench that runs in a
browser tab and nowhere else.
Open a file, turn its pages, rotate one, drop one, lay it out two to a sheet, write across it, strip what runs rather than shows, save it back out — and none of it leaves the machine, because there is nowhere for it to go. The whole tool is one wasm binary the browser downloads once and a service worker then keeps, so the second visit works with the network off and so does the first, once loaded.
then serve web/ over HTTP.
Every change is applied, written, and read back¶
Before it is drawn. So what is on the screen is what would come out of Save, rather than a picture of what was meant to happen.
How it is checked¶
The workbench is a plain Go type with no build tag, so a native test drives the whole of it against a byte buffer: it opens a document built in the test, presses a control at a pixel on the strip rather than calling its handler, and looks at what got drawn.
Then in a real browser, over the DevTools protocol with nothing eyeballed: Chrome loads the shell, the wasm starts, the file picker is intercepted and handed a PDF, and the canvas pixels are read back to prove the page arrived. That check runs in CI, and it earned its keep at once — a file arriving from the browser has no event to be drawn on, so the canvas simply never changed.