The old fixture ran the branch into the end of p1, so the T-patch lived
beyond the host (x>100) and the probe point [92,0] sat outside it under
any code behaviour: deleting the cutPartitionBody flatMap over patches
kept all subtests green (#188, found at the #132 code review).
The branch now meets the middle of the span, putting both node patches
inside the default opening's slot. The test proves its own fixture first:
an uncut run must show the patches bridging the slot, so if the geometry
ever stops producing them the control goes red instead of silently
devaluing the real assertion. Mutation-checked: reverting the flatMap
fails exactly this test, 888/889.
Issue: #188
User-Visible: no
Sergey Matyunin