This directory contains comprehensive language-agnostic JSON test fixtures for validating TOON implementations against the specification. These fixtures cover all specification requirements and provide a standardized conformance test suite.

The test fixtures serve multiple purposes:

• Conformance validation: Verify implementations follow the specification
• Regression testing: Catch behavioral changes across versions
• Implementation guide: Demonstrate expected encoding/decoding behavior
• Cross-language consistency: Ensure all implementations produce identical output

tests/
├── fixtures.schema.json    # JSON Schema for fixture validation
├── fixtures/
│   ├── encode/             # Encoding tests (JSON → TOON)
│   │   ├── primitives.json
│   │   ├── objects.json
│   │   ├── arrays-primitive.json
│   │   ├── arrays-tabular.json
│   │   ├── arrays-nested.json
│   │   ├── arrays-objects.json
│   │   ├── delimiters.json
│   │   ├── whitespace.json
│   │   ├── options.json
│   │   └── key-folding.json
│   └── decode/             # Decoding tests (TOON → JSON)
│       ├── primitives.json
│       ├── numbers.json
│       ├── objects.json
│       ├── arrays-primitive.json
│       ├── arrays-tabular.json
│       ├── arrays-nested.json
│       ├── delimiters.json
│       ├── whitespace.json
│       ├── root-form.json
│       ├── validation-errors.json
│       ├── indentation-errors.json
│       ├── blank-lines.json
│       └── path-expansion.json
└── README.md               # This file

All test fixtures follow a standard JSON structure defined in fixtures.schema.json:

{
  "version": "1.4",
  "category": "encode",
  "description": "Brief description of test category",
  "tests": [
    {
      "name": "descriptive test name",
      "input": "JSON value or TOON string",
      "expected": "TOON string or JSON value",
      "options": {},
      "specSection": "7.2",
      "note": "Optional explanation"
    }
  ]
}

{
  "delimiter": ",",
  "indent": 2,
  "keyFolding": "safe",
  "flattenDepth": 3
}

• delimiter: "," (comma, default), "\t" (tab), or "|" (pipe). Affects encoder output; decoders parse the delimiter declared in array headers
• indent: Number of spaces per indentation level (default: 2)
• keyFolding: "off" (default) or "safe". Enables key folding to collapse single-key object chains into dotted-path notation (v1.5+)
• flattenDepth: Integer. Maximum depth to fold key chains when keyFolding is "safe" (default: Infinity). Values less than 2 have no practical folding effect (v1.5+)

{
  "indent": 2,
  "strict": true,
  "expandPaths": "safe"
}

• indent: Expected number of spaces per indentation level (default: 2)
• strict: Enable strict validation (default: true). When expandPaths is "safe", strict mode controls conflict resolution: errors on conflicts when true, LWW when false (v1.5+)
• expandPaths: "off" (default) or "safe". Enables path expansion to split dotted keys into nested object structures (v1.5+)

Error tests use shouldError: true to indicate that the test expects an error to be thrown:

{
  "name": "throws on array length mismatch",
  "input": "tags[3]: a,b",
  "expected": null,
  "shouldError": true,
  "options": { "strict": true }
}

Note: Error tests do not specify expected error messages, as these are implementation-specific and vary across languages.

To validate your TOON implementation against these fixtures:

1. Load a fixture file from fixtures/encode/ or fixtures/decode/.
2. Iterate through the tests array in the fixture.
3. For each test case:
   • If shouldError is true: verify your implementation throws an error.
   • Otherwise: assert that your encoder/decoder produces the expected output when given the input.
4. Pass options from test.options to your encoder/decoder (if present).

The fixture format is language-agnostic JSON, so you can load and iterate it using your language's standard JSON parser and test framework.

All fixture files should validate against fixtures.schema.json. You can use standard JSON Schema validators:

# Using ajv-cli
npx ajv-cli validate -s fixtures.schema.json -d "fixtures/**/*.json"

# Using check-jsonschema (Python)
pip install check-jsonschema
check-jsonschema --schemafile fixtures.schema.json fixtures/**/*.json

To contribute new test cases:

1. Identify the category: Which fixture file should contain the test?
2. Follow the format: Use the structure defined in fixtures.schema.json
3. Add spec references: Link to relevant specification sections
4. Validate: Ensure your fixture validates against the schema
5. Test with reference implementation: Verify expected output is correct
6. Submit PR: Include clear description of what the test validates

See CONTRIBUTING.md for detailed guidelines.

The reference implementation in TypeScript/JavaScript is maintained at: github.com/toon-format/toon

If you find:

• Test cases that contradict the specification
• Missing coverage for edge cases
• Ambiguous expected outputs
• Schema validation issues

Please open an issue with:

• Fixture file and test case name
• Description of the issue
• Proposed fix (if applicable)

These test fixtures are released under the MIT License, the same as the specification.