[
  {
    "version": "1",
    "caseId": "dob-leap-400",
    "input": "2000-02-29",
    "context": "2026-09-06",
    "expected": "accept",
    "expectedValue": "26",
    "note": "The 400-year rule makes 2000 a leap year."
  },
  {
    "version": "1",
    "caseId": "dob-leap-century",
    "input": "1900-02-29",
    "context": "2026-09-06",
    "expected": "reject",
    "expectedValue": "",
    "note": "1900 is not a leap year; reject Excel's fictitious day."
  },
  {
    "version": "1",
    "caseId": "dob-leap-common",
    "input": "2001-02-29",
    "context": "2026-09-06",
    "expected": "reject",
    "expectedValue": "",
    "note": "Common year."
  },
  {
    "version": "1",
    "caseId": "dob-april-31",
    "input": "2000-04-31",
    "context": "2026-09-06",
    "expected": "reject",
    "expectedValue": "",
    "note": "Reject instead of rolling into May."
  },
  {
    "version": "1",
    "caseId": "dob-eighteen",
    "input": "2008-09-06",
    "context": "2026-09-06",
    "expected": "accept",
    "expectedValue": "18",
    "note": "Exactly 18 on the fixed reference date."
  },
  {
    "version": "1",
    "caseId": "dob-before-eighteen",
    "input": "2008-09-07",
    "context": "2026-09-06",
    "expected": "accept",
    "expectedValue": "17",
    "note": "Do not calculate age using years alone."
  },
  {
    "version": "1",
    "caseId": "dob-epoch",
    "input": "1970-01-01",
    "context": "2026-09-06",
    "expected": "accept",
    "expectedValue": "56",
    "note": "A real date must remain distinguishable from a missing value."
  },
  {
    "version": "1",
    "caseId": "dob-pre-1900",
    "input": "1899-12-31",
    "context": "2026-09-06",
    "expected": "accept",
    "expectedValue": "126",
    "note": "Text round trip; do not rely on Excel date serials."
  },
  {
    "version": "1",
    "caseId": "dob-future",
    "input": "2026-09-07",
    "context": "2026-09-06",
    "expected": "reject",
    "expectedValue": "",
    "note": "Tomorrow is already too late."
  },
  {
    "version": "1",
    "caseId": "dob-today",
    "input": "2026-09-06",
    "context": "2026-09-06",
    "expected": "accept",
    "expectedValue": "0",
    "note": "Newborn; this policy has no eligibility gate."
  },
  {
    "version": "1",
    "caseId": "dob-ambiguous",
    "input": "06/09/2008",
    "context": "2026-09-06",
    "expected": "reject",
    "expectedValue": "",
    "note": "Reject ambiguous locale formatting."
  },
  {
    "version": "1",
    "caseId": "dob-empty",
    "input": "",
    "context": "2026-09-06",
    "expected": "reject",
    "expectedValue": "",
    "note": "Required field."
  },
  {
    "version": "1",
    "caseId": "dob-leap-before",
    "input": "2008-02-29",
    "context": "2026-02-28",
    "expected": "accept",
    "expectedValue": "17",
    "note": "March 1 anniversary convention in a common year."
  },
  {
    "version": "1",
    "caseId": "dob-leap-after",
    "input": "2008-02-29",
    "context": "2026-03-01",
    "expected": "accept",
    "expectedValue": "18",
    "note": "The declared anniversary has arrived."
  }
]