The already-committed nav_briennecarlus.af/nav_empyrean.af/nav_lockandkeyjaw.af
fixtures (checkpoint/recall/portal2 node coverage, clean metaf headers)
were exercised by the model-equality proofs (parse, parse-write-parse,
binary-import-matches-af) but never by the REAL byte-identical writer-output
theory, which only ever covered nav_ab.af. Converted
WriterOutputMatchesMetafCanonicalEmissionNavOnly into a Theory over all
four nav-only fixtures.
Added two more coverage gaps this round's audit named:
- StringCellStripsEmbeddedNewlineAtConstructionNotJustOnWrite pins
VtankCell.String's gy.cs:84 newline strip (construction-time, not just
at WriteTo).
- RealAstFixturesRoundTripByteIdentical extends the existing schema-only
owner-{a,b,c}.ast coverage to a real parse -> Render() byte-identity
round trip, the same proof-4 rigor MetafSerializerTests already applies
to .af fixtures.
No writer bug surfaced in the extended nav theory or the .ast round trip —
both already passed; these are coverage-closing additions, not fixes.
Verified each new test has teeth via a temporary synthetic mutation rather
than a real revert (there is no production fix to revert here): the
string-cell test was checked against a temporarily-unstripped VtankCell.String
(failed, restored), and the .ast round-trip was checked against a
temporarily LF-only VtankWriter.AppendLine (all three .ast cases failed,
the four nav cases were unaffected since MetafSerializer's .af writer is a
separate code path from VtankUsdDocument's "y" grammar writer — restored).
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
2566dad1d3