bf-3y9r (verify position propagation). The wiring from prior children
(bf-5lii -> bf-69ym -> bf-u7ds -> bf-95tx) already traces a posted node
position through simulator VirtualNodeStore -> fleet.Registry (SQLite) ->
fusion.Engine.nodePos mirror, and bf-95tx's TestPositionPropagation_
FullPipeline logs the value agreeing at all three stages. What was missing
was a single end-to-end assertion that those positions reach the engine's
*accumulation grid* and actually drive localization -- the last inch the
bead's acceptance criterion ("Verify positions reach the fusion engine
accumulation grid") asks for.
Add TestPositionPropagation_ReachesAccumulationGrid: posts two
explicitly-positioned nodes through the simulator REST API, runs one Fuse
step with a link between the two MACs the engine now holds, and asserts a
blob localizes near the link midpoint (confidence 1.0, 1 active link). A
blob there is only reachable if both endpoints' positions are in the grid
lookup -- AddLinkInfluence reads nodePos[mac] for both endpoints, and a
missing/co-located position yields no peak
(cf. TestEngine_CoLocatedOriginYieldsNoPeaks). The grid trace logs the
value's path under `go test -v`:
[grid] position propagation midpoint=(3.00,1.00) peak=(2.90,0.90,0.90) conf=1.000 activeLinks=1
No production wiring change was needed -- prior children completed it; this
bead is verification, with this test as its lock-in.
Co-Authored-By: Claude <noreply@anthropic.com>
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