{
  "specVersion": "1.0",
  "description": "LC-JSON 1.0 conformance test corpus. Conforming consumers MUST pass every valid case and fail every invalid case.",
  "valid": [
    {
      "file": "valid/01-course-minimal.json",
      "schema": "course.schema.json",
      "demonstrates": ["§3.2 root fields", "§3.3 course artifact", "§4.5 camelCase property naming"]
    },
    {
      "file": "valid/02-question-set-minimal.json",
      "schema": "question-set.schema.json",
      "demonstrates": ["§3.2 root fields", "§3.3 questionSet artifact", "§4.2 canonical camelCase question discriminator"]
    },
    {
      "file": "valid/03-unknown-optional-field.json",
      "schema": "course.schema.json",
      "demonstrates": ["§5.4 unknown fields ignored — forward-compat reservation"]
    },
    {
      "file": "valid/04-reserved-question-type.json",
      "schema": "question-set.schema.json",
      "demonstrates": ["§5.5 reserved enum values accepted on import", "§6 Reserved and unknown types — base case"]
    },
    {
      "file": "valid/05-reserved-type-with-extensions.json",
      "schema": "question-set.schema.json",
      "demonstrates": ["§6.4 round-trip preservation — reserved type with tool-specific extension fields (imageUrl, regions, correctRegionId) MUST be preserved in full across consumer read/write cycles (semantic preservation; key order is producer-discretion per §6.2)"]
    },
    {
      "file": "valid/06-html-with-video-track.json",
      "schema": "course.schema.json",
      "demonstrates": ["§11 + HTML_SAFETY.md §7 — <video> with captions <track>, conforming media handling (controls, poster, preload, no autoplay/loop)"]
    },
    {
      "file": "valid/07-placement-sentence.json",
      "schema": "placement.schema.json",
      "demonstrates": ["placement.schema.json — sentence-mode placement with placements:[{gap, item}] and a distractor item"]
    },
    {
      "file": "valid/08-placement-paragraph.json",
      "schema": "placement.schema.json",
      "demonstrates": ["placement.schema.json — paragraph-mode placement with @@@N markers alone on their paragraphs"]
    },
    {
      "file": "valid/09-placement-section-label.json",
      "schema": "placement.schema.json",
      "demonstrates": ["placement.schema.json — sectionLabel-mode placement with markers at section starts (IELTS Matching Headings / analytical meta-labels)"]
    },
    {
      "file": "valid/10-placement-toefl-decoy-gaps.json",
      "schema": "placement.schema.json",
      "demonstrates": ["placement.schema.json — TOEFL Sentence Insertion variant: 4 @@@N markers in passage but a single placements[] entry; the unanswered markers are valid decoy positions"]
    },
    {
      "file": "valid/11-rtl-writing-systems.json",
      "schema": "course.schema.json",
      "demonstrates": ["ACCESSIBILITY.md §6.2 — `language` propagation and `dir` preservation on HTML-bearing fields", "HTML_SAFETY.md §3.1 — universal `lang`/`dir` attributes on inline (span) and block (blockquote) elements", "mixed-direction content: LTR document with embedded RTL spans + per-block RTL blockquotes across four major RTL writing systems (Arabic, Urdu, Persian, Hebrew)"]
    },
    {
      "file": "valid/12-accessibility-round-trip.json",
      "schema": "course.schema.json",
      "demonstrates": ["NORMATIVE §12.1 — base-conformance accessibility-preservation floor: `alt` on `<img>`, `<track>` on `<video>`, `lang`/`dir` on HTML spans, document-root `language`/`supportLanguage`, and `x-`-namespaced accessibility metadata on a reserved-type question MUST all round-trip through any conforming consumer"]
    },
    {
      "file": "valid/13-symbolic-empty-prompt.json",
      "schema": "question-set.schema.json",
      "demonstrates": ["TD-212 / rc.2 — `prompt` is non-authoritative for symbolic types: a simpleGapFill with `prompt: \"\"` is valid (minLength 0), meaning carried by the structured `sentence`/`acceptedAnswers` fields"]
    },
    {
      "file": "valid/14-simple-gap-fill.json",
      "schema": "simple-gap-fill.schema.json",
      "demonstrates": ["simple-gap-fill.schema.json — per-type valid case: single @@@ marker in `sentence`, non-empty `acceptedAnswers`"]
    },
    {
      "file": "valid/15-multiple-choice.json",
      "schema": "multiple-choice.schema.json",
      "demonstrates": ["multiple-choice.schema.json — per-type valid case: `options` fully covered by `optionsAndPoints` with exactly one positive-points entry (VALIDATION.md §9.3)"]
    },
    {
      "file": "valid/16-word-bank-cloze.json",
      "schema": "word-bank-cloze.schema.json",
      "demonstrates": ["word-bank-cloze.schema.json — per-type valid case: @@@N marker set equals `gapAcceptedAnswers` key set (VALIDATION.md §9.4 / KG-1), word bank includes a distractor"]
    },
    {
      "file": "valid/17-multi-gap-cloze.json",
      "schema": "multi-gap-cloze.schema.json",
      "demonstrates": ["multi-gap-cloze.schema.json — per-type valid case: free-text gaps, multiple accepted answers per gap, no commas/colons in answers (VALIDATION.md §9.5)"]
    },
    {
      "file": "valid/18-multiple-choice-cloze.json",
      "schema": "multiple-choice-cloze.schema.json",
      "demonstrates": ["multiple-choice-cloze.schema.json — per-type valid case: `gapOptions` and `correctAnswers` key sets equal the @@@N marker set, indices in bounds (VALIDATION.md §9.6 / KG-5)"]
    },
    {
      "file": "valid/19-short-answer.json",
      "schema": "short-answer.schema.json",
      "demonstrates": ["short-answer.schema.json — per-type valid case: non-empty `acceptedAnswers`, first entry canonical"]
    },
    {
      "file": "valid/20-essay.json",
      "schema": "essay.schema.json",
      "demonstrates": ["essay.schema.json — per-type valid case: `expectedAnswer` model answer present, maxWords >= minWords (VALIDATION.md §9.8)"]
    },
    {
      "file": "valid/21-sentence-transformation.json",
      "schema": "sentence-transformation.schema.json",
      "demonstrates": ["sentence-transformation.schema.json — per-type valid case: exactly one @@@ in `targetSentence`, sequential 1-based `acceptedChunks` keys, uppercase `keyword` (VALIDATION.md §9.9)"]
    },
    {
      "file": "valid/22-matching-pairs.json",
      "schema": "matching.schema.json",
      "demonstrates": ["matching.schema.json — pairs sub-shape: matchingMode:'pairs' with `pairs[]` (and no `categories[]`), distractor in the match pool (NORMATIVE §5.6 randomization applies on render)"]
    },
    {
      "file": "valid/23-matching-classification.json",
      "schema": "matching.schema.json",
      "demonstrates": ["matching.schema.json — classification sub-shape: matchingMode:'classification' with `categories[]` (and no `pairs[]`), many-to-one item-into-category"]
    },
    {
      "file": "valid/24-ordering-kendall.json",
      "schema": "ordering.schema.json",
      "demonstrates": ["ordering.schema.json — per-type valid case: orderingUnit:'sentence' with scoringMode:'kendall' partial credit (TD-163)"]
    },
    {
      "file": "valid/25-grading-combination-matrix.json",
      "schema": "course.schema.json",
      "demonstrates": ["exercise-item.schema.json + quiz-item.schema.json — grading combination matrix: all four graded/ungraded × exercise/quiz combinations are valid (`isGraded` is policy, item type is structure — see ITEM_PATTERNS.md)", "VALIDATION.md §4 / KG-6 — objectives pool with resolvable courseObjectiveIds/objectiveIds references"]
    }
  ],
  "invalid": [
    {
      "file": "invalid/01-missing-document-type.json",
      "violatedClause": "§3.2",
      "violation": "Missing required root field: documentType"
    },
    {
      "file": "invalid/02-missing-spec-version.json",
      "violatedClause": "§3.2",
      "violation": "Missing required root field: specVersion"
    },
    {
      "file": "invalid/04-pascal-case-question-type.json",
      "violatedClause": "§4.2",
      "violation": "Question type discriminator emitted in PascalCase ('TrueFalseQuestion') instead of canonical camelCase ('trueFalseQuestion')"
    },
    {
      "file": "invalid/05-non-uuid-global-id.json",
      "violatedClause": "§4.4",
      "violation": "Question globalId is not a valid RFC 4122 UUID"
    },
    {
      "file": "invalid/06-pascal-case-property.json",
      "violatedClause": "§4.5",
      "violation": "Property name emitted in PascalCase ('Title') instead of canonical camelCase ('title')"
    },
    {
      "file": "invalid/07-spec-version-2-0.json",
      "violatedClause": "§5.2",
      "violation": "specVersion '2.0' has major version > 1; consumer MUST reject"
    },
    {
      "file": "invalid/08-spec-version-malformed.json",
      "violatedClause": "§3.2",
      "violation": "specVersion 'one-point-zero' does not match the required pattern ^[0-9]+\\.[0-9]+(\\.[0-9]+)?$"
    },
    {
      "file": "invalid/09-uppercase-item-type.json",
      "violatedClause": "§4.2",
      "violation": "Item type discriminator emitted in uppercase ('CONTENT') instead of canonical lowercase ('content')"
    },
    {
      "file": "invalid/10-wrapped-envelope.json",
      "violatedClause": "§4.1",
      "violation": "Document uses a wrapped envelope ({\"course\":{...}}) instead of the canonical flat root"
    },
    {
      "file": "invalid/11-bare-payload.json",
      "violatedClause": "§4.1",
      "violation": "Document uses a bare payload (no documentType, no $schema) instead of the canonical flat root"
    },
    {
      "file": "invalid/12-unit-missing-global-id.json",
      "violatedClause": "§4.4",
      "violation": "Unit is missing the required globalId field — every Unit/Lesson/Item/Question MUST carry a globalId for stable identity across re-imports"
    },
    {
      "file": "invalid/13-html-with-script.json",
      "violatedClause": "§11 + HTML_SAFETY.md §2.4 + §3.5",
      "violation": "ContentItem.html contains a forbidden <script> element and an onclick event handler — both are XSS-class violations the consumer MUST reject"
    },
    {
      "file": "invalid/14-placement-missing-placements.json",
      "violatedClause": "placement.schema.json (required: placements)",
      "violation": "placement question is missing the required placements[] array"
    },
    {
      "file": "invalid/15-placement-empty-placements.json",
      "violatedClause": "placement.schema.json (placements.minItems: 1)",
      "violation": "placement.placements[] is an empty array; minItems is 1 (the TOEFL variant still requires at least one placement entry — the unanswered markers are decoy gaps, not zero placements)"
    },
    {
      "file": "invalid/16-placement-orphan-gap.json",
      "violatedClause": "placement domain rule (validate_course.py)",
      "violation": "placements[].gap = 7 references a marker (@@@7) that is not present in passage; orphan placement entries fail validation"
    },
    {
      "file": "invalid/17-placement-duplicate-gap.json",
      "violatedClause": "placement domain rule (validate_course.py)",
      "violation": "placements[] contains duplicate gap value (gap: 1 appears twice); each gap may only have one placement entry"
    },
    {
      "file": "invalid/18-placement-bad-placement-unit.json",
      "violatedClause": "placement.schema.json (placementUnit.enum)",
      "violation": "placementUnit value 'word' is outside the enum — placement supports only 'sentence', 'paragraph', and 'sectionLabel'; word-level placement is covered by wordBankCloze"
    },
    {
      "file": "invalid/19-placement-gap-as-string.json",
      "violatedClause": "placement.schema.json (placements[].gap.type: integer)",
      "violation": "placements[].gap is a string ('1') rather than an integer (1); the @@@N marker convention is integer-keyed"
    },
    {
      "file": "invalid/20-missing-language.json",
      "violatedClause": "question-set.schema.json (required: language) + ACCESSIBILITY.md §6.1 / WCAG 3.1.1 Language of Page",
      "violation": "QuestionSet root is missing the required `language` field. As of rc.1, `language` is in the required[] list of both course.schema.json and question-set.schema.json because a delivering consumer needs it to set the rendering surface's `lang` attribute (WCAG 3.1.1) and to drive RTL detection. A document without root `language` cannot be rendered accessibly."
    },
    {
      "file": "invalid/21-mcq-no-correct-option.json",
      "violatedClause": "VALIDATION.md §9.3 (KG-3 closure) — multipleChoice domain rule (validate_course.py: validate_multiple_choice)",
      "violation": "MultipleChoice with all-zero `optionsAndPoints` values. An MCQ MUST have at least one option with points > 0; otherwise no submission can earn credit. Surfaced as an ERROR by validate_course.py's validate_multiple_choice domain pass."
    },
    {
      "file": "invalid/22-mcq-options-points-missing-entry.json",
      "violatedClause": "VALIDATION.md §9.3 (KG-4 closure) — multipleChoice domain rule (validate_course.py: validate_multiple_choice)",
      "violation": "MultipleChoice `optionsAndPoints` is missing an entry for the third option (`gamma`). Every value in `options` MUST appear as a key in `optionsAndPoints` so the consumer can score it deterministically."
    },
    {
      "file": "invalid/23-word-bank-cloze-gap-count-mismatch.json",
      "violatedClause": "VALIDATION.md §9.4 (KG-1 closure) — wordBankCloze domain rule (validate_course.py: validate_word_bank_cloze + _check_cloze_gap_consistency)",
      "violation": "wordBankCloze passage contains @@@1, @@@2, @@@3 but `gapAcceptedAnswers` only has keys for gaps 1 and 2. The marker set in `passage` MUST equal the key set in `gapAcceptedAnswers`; otherwise the third gap has no accepted answer and the question cannot be graded."
    },
    {
      "file": "invalid/24-multiple-choice-cloze-index-out-of-bounds.json",
      "violatedClause": "VALIDATION.md §9.6 (KG-5 closure) — multipleChoiceCloze domain rule (validate_course.py: validate_multiple_choice_cloze)",
      "violation": "multipleChoiceCloze `correctAnswers['1']` is 5 but `gapOptions['1']` has only 2 options (valid indices 0..1). The correctAnswers index MUST be within the bounds of the corresponding gapOptions array; otherwise no submission can match the correct answer."
    },
    {
      "file": "invalid/25-sentence-transformation-multiple-markers.json",
      "violatedClause": "VALIDATION.md §9.9 — sentenceTransformation domain rule (validate_course.py: validate_sentence_transformation)",
      "violation": "SentenceTransformation `targetSentence` contains two `@@@` markers ('The @@@ was three @@@ ago.'). The convention is exactly one `@@@` regardless of `acceptedChunks` count — chunks are sequential answer pieces typed at that single position, not separate gaps. Multiple markers are ambiguous (which chunk goes where?) and are rejected with an ERROR."
    },
    {
      "file": "invalid/26-real-content-empty-prompt.json",
      "violatedClause": "VALIDATION.md (question-base prompt rule) — real-content empty-prompt domain rule (validate_course.py: validate_question)",
      "violation": "trueFalseQuestion with `prompt: \"\"`. The schema permits an empty prompt (minLength 0), but for the four real-content types (trueFalseQuestion, multipleChoice, shortAnswer, essay) the prompt IS the question, so an empty prompt is an authoring error caught by the validator's domain pass with an ERROR. (The same empty prompt on a symbolic type — see valid/13 — is valid.)"
    },
    {
      "file": "invalid/27-true-false-non-boolean-answer.json",
      "violatedClause": "true-false-question.schema.json (correctAnswer.type: boolean)",
      "violation": "trueFalseQuestion `correctAnswer` is the string 'absolutely' rather than a JSON boolean. `correctAnswer` is the single source of truth for scoring and MUST be a boolean."
    },
    {
      "file": "invalid/28-simple-gap-fill-no-marker.json",
      "violatedClause": "simple-gap-fill.schema.json (sentence.pattern: @@@)",
      "violation": "simpleGapFill `sentence` contains no `@@@` gap marker, so there is no gap for the learner to fill. The schema requires the marker via the `@@@` pattern."
    },
    {
      "file": "invalid/29-simple-gap-fill-missing-accepted-answers.json",
      "violatedClause": "simple-gap-fill.schema.json (required: acceptedAnswers)",
      "violation": "simpleGapFill is missing the required `acceptedAnswers` array — without it no submission can be scored."
    },
    {
      "file": "invalid/30-multi-gap-cloze-comma-in-answer.json",
      "violatedClause": "VALIDATION.md §9.5 — multiGapCloze domain rule (validate_course.py: validate_multi_gap_cloze)",
      "violation": "multiGapCloze accepted answer 'bread, butter and jam' contains a comma. Some consuming applications encode multi-gap submissions as 'gap:answer,gap:answer' on the wire, so commas or colons inside an answer can be silently truncated during scoring — a learner typing the exact accepted answer would be marked wrong. ERROR-tier."
    },
    {
      "file": "invalid/31-short-answer-missing-accepted-answers.json",
      "violatedClause": "short-answer.schema.json (required: acceptedAnswers)",
      "violation": "shortAnswer is missing the required `acceptedAnswers` array — without it no submission can be scored."
    },
    {
      "file": "invalid/32-essay-missing-expected-answer.json",
      "violatedClause": "essay.schema.json (required: expectedAnswer)",
      "violation": "essay is missing the required `expectedAnswer` (model answer / sample response) field."
    },
    {
      "file": "invalid/33-matching-pairs-missing-pairs.json",
      "violatedClause": "matching.schema.json (if matchingMode:'pairs' then required: pairs)",
      "violation": "matching with matchingMode:'pairs' but no `pairs[]` array. The matchingMode discriminator selects the required sub-shape: 'pairs' requires `pairs[]`, 'classification' requires `categories[]`."
    },
    {
      "file": "invalid/34-matching-mode-shape-collision.json",
      "violatedClause": "matching.schema.json (then.not.required: categories)",
      "violation": "matching carries BOTH `pairs[]` and `categories[]`. The two sub-shapes are mutually exclusive — a document carrying both is ambiguous about which one scores, and the schema's conditional `not` clauses reject the collision."
    },
    {
      "file": "invalid/35-ordering-single-item.json",
      "violatedClause": "ordering.schema.json (items.minItems: 2)",
      "violation": "ordering `items` has a single tile; with fewer than two tiles there is no ordering task. minItems is 2."
    },
    {
      "file": "invalid/36-ordering-bad-scoring-mode.json",
      "violatedClause": "ordering.schema.json (scoringMode.enum)",
      "violation": "ordering `scoringMode` is 'lenient', outside the enum — only 'strict' (exact-order, all-or-nothing) and 'kendall' (Kendall tau partial credit) are defined."
    },
    {
      "file": "invalid/37-content-sequence-orphan-related-id.json",
      "violatedClause": "VALIDATION.md §7.4 — ContentSequence referential-integrity domain rule (validate_course.py: validate_item)",
      "violation": "ContentSequence `relatedItemIds` references a globalId that does not exist in the lesson. Every relatedItemId MUST resolve to an exercise/quiz item declared earlier in the same lesson; orphan references are an ERROR. (Note: objectiveIds referential integrity — KG-6 — is deliberately WARN-tier and therefore exercised by valid/25, not by an invalid fixture.)"
    },
    {
      "file": "invalid/38-word-bank-cloze-empty-word-bank.json",
      "violatedClause": "word-bank-cloze.schema.json (wordBank.minItems: 1)",
      "violation": "wordBankCloze `wordBank` is an empty array — the learner has no words to choose from. minItems is 1."
    },
    {
      "file": "invalid/39-question-missing-global-id.json",
      "violatedClause": "§4.4 + question-base.schema.json (required: globalId)",
      "violation": "Question is missing the required `globalId` field — every Unit/Lesson/Item/Question MUST carry a globalId for stable identity across re-imports. Complements invalid/12 (unit-level) at the question level."
    },
    {
      "file": "invalid/40-duplicate-global-id.json",
      "violatedClause": "§4.4 — globalId uniqueness domain rule (validate_course.py: _collect_duplicate_global_id_errors)",
      "violation": "Two questions in different items carry the same globalId (case-varied: ...000d vs ...000D). Within a single document, globalId values MUST be unique across all entities; comparison is case-insensitive. A consumer keyed on globalId cannot tell the entities apart, so re-import matching breaks."
    }
  ]
}