Upstream here. The reason the suite fails like that is that mandatory-for-testing dependencies were also removed.
The test suite runs on Travis CI in 10-12 minutes. On Debian CI, 15 minutes. For comparison ffmpeg, another compute intensive CLI program, takes 10 minutes. This is an OCR program and OCR takes a long time. There are opportunities to speed up testing on my end but no low hanging fruit without removing tests. I've done the obvious: use all cores, use caches and dummies where possible. Some OCR on the fly is essential because Tesseract is complex enough that output is not identical across platforms. Preserving the dynamically created tests/cache/ folder between test runs, if possible in Debian CI, would speed it up a lot. I could mark a subset of essential tests for packagers so that Debian CI can specify it only wants those. There's a number of tests that are very unlikely to pass upstream testing (macOS and Ubuntu) then somehow fail downstream in Debian.
