Cutdown conformance corpus

This directory contains the golden test fixtures for the Cutdown language spec. A compliant parser must pass all of them.

Structure

Fixtures are organized by spec section. Each subdirectory maps to one section:

tests/
  003-document-model/
  004-block-segments/
  005-inline-segments/
  006-universal-attributes/
  008-escaping/
  010-block-structure/
  012-whitespace-rules/
  diagnostics/          ← one fixture per CDN-xxxx diagnostic code

A test runner must walk all *.yaml files recursively — loading only the top level will silently pass zero tests.

Fixture format

Each .yaml file is a single fixture:

id: emphasis-basic
section: "5.2"
description: "__ delimiters produce Emphasis; single _ is literal text"

input: "__bold__"

ast:
  - type: Paragraph
    children:
      - type: Emphasis
        children:
          - type: Text
            value: bold

Fields

Exactly ONE OF ast or pages MUST be present.

Assertions

AST matching uses a deep subset match:

• All keys present in the expected object MUST exist in the actual output with identical values.
• Extra keys in the actual output MAY exist and are ignored (implementations may add position info, etc.).
• Arrays MUST be the same length; each element is subset-matched recursively.
• Primitives MUST be compared by value (===).

This means a minimal fixture only needs to assert the fields it cares about — it will not break if the parser adds new optional fields later.

Diagnostics matching is order-independent:

• Every { code, level } entry listed under diagnostics MUST appear in the actual output.
• No diagnostic MAY appear in the actual output that is not listed in the fixture.
• If diagnostics is omitted entirely, the parser MUST produce zero diagnostics.

ast vs pages

ast matches the children array of the first page — the common case for single-page documents:

ast:
  - type: Paragraph
    children:
      - type: Text
        value: Hello

pages matches the full Document.children array and is used when the fixture tests page-splitting (PageBreak, Meta block pagination). A Ghost Page is written {}:

pages:
  - children:
      - type: Paragraph
        children:
          - type: Text
            value: First
  - {}

Attribute fixtures

Attributes are asserted as an ordered array of { key, value } objects. The class shorthand (.class) produces value: string[] (array of strings); all other values are plain strings:

ast:
  - type: List
    attributes:
      - key: class
        value: [list-class]
    children:
      - type: ListItem
        attributes:
          - key: class
            value: [item-class]

Diagnostic fixtures

Fixtures in diagnostics/ test warning behaviour. The fixture asserts both the AST produced (recovery output) and the diagnostic code emitted:

id: cdn-0001-unclosed-codeblock
section: "4.4"
description: "Unclosed ``` fence; content runs to end of document; CDN-0001 warning emitted"

input: "```python\nx = 1\n"

ast:
  - type: CodeBlock
    language: python
    content: x = 1

diagnostics:
  - code: CDN-0001
    level: warning

ID and filename conventions

• ID is kebab-case: code-block-basic, cdn-0001-unclosed-codeblock
• Filename matches ID exactly: code-block-basic.yaml
• Diagnostic fixtures are prefixed with the code: cdn-0001-*.yaml
• Variant fixtures suffix the base name: emphasis-basic, emphasis-triple, emphasis-unclosed

Contributing a test

1. Identify the spec section the fixture covers.
2. Create tests/<section-dir>/<id>.yaml. Use an existing fixture in that directory as a template.
3. Fill all required fields. Keep input minimal — test one behaviour per fixture.
4. Verify the id is unique across the entire corpus (no two fixtures share an id).
5. Open a PR. See CONTRIBUTION.md for process.