Generate labeled JSONL date-validation cases, including century leap-year exceptions, impossible month days and strict-format failures.

A practical example

Choose a year range in the sample JSON. Generate JSONL fixtures with an input, expected boolean and explanation. The downloadable pack contains a command-line conformance runner and a reference validator. The contract is strict Gregorian YYYY-MM-DD civil dates; date-times and timezones are outside scope.

Input

{
  "start_year": 1996,
  "end_year": 2040
}

Actual tool output

{
  "cases": 324,
  "contract": "Strict YYYY-MM-DD Gregorian civil dates, years 0001\u20139999. Date-times, timezone values and surrounding whitespace are rejected. No leap-second or historical-calendar claim.",
  "invalid": 221,
  "usage": "Feed each input to your validator. Compare its boolean result to expected. Use runner.js in the purchased pack to test a Node module automatically.",
  "valid": 103
}

This example was executed by the same engine shipped in the product. The release passed 1472 executable regression checks. Large reports can be viewed and downloaded in full in the workbench.

Use it in your own workflow

Open Calendar Boundary Lab to try the online tool. The optional paid pack adds an offline copy, editable source, regression checks and a commercial customization license. Test it on representative inputs before relying on it.