YAML Conformance
Lanexio™ Parser targets full YAML 1.2.2 conformance against the yaml-test-suite, the official YAML language test corpus. Conformance is measured on two independent axes: structural validity (does the parser produce correct event streams for valid input) and error rejection (does the parser correctly reject malformed input).
Structural conformance
Section titled “Structural conformance”268 of 268 valid cases pass under the exact-count conformance gate. Every YAML document in the test suite that the spec defines as valid parses to the correct event stream.
The conformance gate is an exact-count assertion: expect(passed).toBe(268). This is not a ceiling or a “less than or equal” check. If a future change regresses a single case, the gate fails.
Error rejection
Section titled “Error rejection”82 of 82 error cases rejected under the exact-count error-rejection gate. The parser identifies and rejects every intentionally malformed YAML document in the test suite.
Error rejection is verified independently from structural conformance. Both axes carry exact-count gates that can only rise.
Four-axis bar
Section titled “Four-axis bar”YAML is verified on all four invariant axes:
| Axis | Result |
|---|---|
| never-throw | 0 throws across full corpus + adversarial fuzz |
| well-formed | corpus WF = 0, 7 fuzz harnesses clean |
| lossless | corpus lossless = 0, byte-exact round-trip |
| conformance | 268/268 valid + 82/82 error |
Test corpus
Section titled “Test corpus”The yaml-test-suite consists of 268 valid input files and 82 error input files organized by case ID. Each case includes the input YAML and the expected event stream. Conformance is measured by comparing the parser’s event output against the expected stream — not by comparing AST structures, which can vary between implementations.
Corpus conformance
Section titled “Corpus conformance”pnpm conformance:suite measured this family over the test_files/yaml corpus on 2026-10-06 at
Lanexio™ Parser version 1.0.0:
| family | valid | invalid | raw | contract-subset | REAL-DEFECT |
|---|---|---|---|---|---|
| yaml | 2068 | 9 | 98.7% | 99.1% (2050/2068) | 18 |
The contract-subset here is the clean valid inputs over all valid inputs (this family carries no artifact buckets), and the 18 REAL-DEFECT entries are valid-classified files that report an error.