Adds SurfaceNetsTests.cs and QuadNormalsTests.cs covering the sign
convention, edge naming, outward winding, vertex placement (midpoint and
unequal-crossing means, origin/cellSize), closed-sphere welding and
Euler characteristic, an ambiguous checkerboard cell's even-but-not-2 edge
usage, open-boundary quad suppression, determinism/ordering, and
face-weighted normals (sliver-vs-large-quad area weighting, unit cube
normals, zero-area/untouched-vertex degenerate case). Adds
stryker-config.json (vstest runner; this project is NUnit 4, not xunit.v3)
and records GameCult.Geometry as scoped, diff-only, in
docs/mutation-testing.md's follow-ups.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
CultMath.Tests is on xunit.v3. Stryker's default vstest runner cannot
capture coverage against xunit.v3's test host and hangs retrying test
sessions indefinitely (observed: 2096 mutants queued, zero completed after
~9 minutes of retries). Stryker's Microsoft.Testing.Platform runner
(-t mtp, still preview) works correctly against xunit.v3 and completed the
same 1351-mutant run in ~4.5 minutes. Pin it in config so a plain
`dotnet stryker` works without a CLI flag.
Add docs/mutation-testing.md: how to run it, the --since form for a single
cut, the triage rules, a known coverage-capture caveat in the mtp runner
(confirmed by hand-mutation against static readonly fields), and the
packages still needing their own config.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
