Conformance plan

NUIF conformance is split into independently testable profiles.

Required suites

1. model — stable IDs, containment, graph references, cycle rules.
2. canonicalization — deterministic text/binary representation and hashes.
3. extensions — used/required negotiation and opaque preservation.
4. layout — authored→resolved fixtures across viewport/context matrices.
5. render — normative geometry/paint/text behavior with declared tolerances.
6. operations — patch replay, inversion, preconditions and deterministic results.
7. merge — three-way semantic conflicts and move/reorder cases.
8. provenance — correspondence retention and fidelity diagnostics.
9. adapter — import/export loss reports and foreign-extension preservation.
10. security — parser depth/size limits, malicious assets and renderer budgets.
11. independent-reproduction — a non-reference package parses/writes the fixture and independently reproduces resolved layout, raster and fidelity.

Test techniques

• golden structural fixtures;
• property-based tests for operation sequences;
• fuzz parsers/codecs and path geometry;
• differential layout checks against browser/Taffy where semantics match;
• metamorphic tests such as encode→decode→encode stability;
• deterministic operation replay;
• visual snapshots with perceptual thresholds only where exact pixels are not normative.

A test result must include implementation version, capability profile, fixture ID and evaluation context. Foreign-reference results additionally include exact oracle versions, generator source revision, raw per-engine observations, a fixture-local measured bound and typed classifications for every divergence.

The implemented adapter suite covers nuif-html-css-0, the separately declared nuif-html-css-v0 responsive-card profile, nuif-svg-0 and nuif-dtcg-scalar-0 with exact export/import, byte-local synchronization and property-attributed rejection. Arbitrary web or SVG source, non-scalar DTCG and other adapter targets remain non-conformant until separately declared profiles pass.

The implemented independent-reproduction suite covers the complete v0 fixture in canonical text and the declared profile-0 layout/render subset. The Python standard-library implementation computes its own boxes and pixels, and the harness compares decoded RGBA so PNG encoder behavior is not mistaken for render divergence. This is an in-repository mechanical reproduction, not evidence of external implementation provenance or standards adoption.

Canonical source.