from-chinese-leap-month-uncommon.js

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// |reftest| skip-if(!this.hasOwnProperty("Temporal")) slow

// Uncommon leap month with 30 days can be far into the past. Computing the

// results can take its time, therefore the test is marked as "slow".

//

// Month -> ISO year

//

// M01L     1461

// M02L     <common>

// M03L     <common>

// M04L     <common>

// M05L     <common>

// M06L     <common>

// M07L     <common>

// M08L     <common>

// M09L     -6482

// M10L     -4633

// M11L     -2172

// M12L     -179

//

// See also "The Mathematics of the Chinese Calendar", Table 21 [1] for a

// distribution of leap months.

//

// [1] https://www.xirugu.com/CHI500/Dates_Time/Chinesecalender.pdf

const monthCodes = [

  "M01L",

  // M02L..M08L are common leap months.

  "M09L",

  "M10L",

  "M11L",

  "M12L",

];

function assertSameISOFields(actual, expected) {

  let actualFields = actual.getISOFields();

  let expectedFields = expected.getISOFields();

  assertEq(typeof actualFields.isoYear, "number");

  assertEq(typeof actualFields.isoMonth, "number");

  assertEq(typeof actualFields.isoDay, "number");

  assertEq(actualFields.isoMonth > 0, true);

  assertEq(actualFields.isoDay > 0, true);

  assertEq(actualFields.isoYear, expectedFields.isoYear);

  assertEq(actualFields.isoMonth, expectedFields.isoMonth);

  assertEq(actualFields.isoDay, expectedFields.isoDay);

const calendar = "chinese";

// Months can have up to 30 days.

const day = 30;

for (let monthCode of monthCodes) {

  let pmd = Temporal.PlainMonthDay.from({calendar, monthCode, day});

  assertEq(pmd.monthCode, monthCode);

  assertEq(pmd.day, day);

  let constrain = Temporal.PlainMonthDay.from({calendar, monthCode, day: day + 1}, {overflow: "constrain"});

  assertEq(constrain.monthCode, monthCode);

  assertEq(constrain.day, day);

  assertSameISOFields(constrain, pmd);

  assertThrowsInstanceOf(() => {

    Temporal.PlainMonthDay.from({calendar, monthCode, day: day + 1}, {overflow: "reject"});

  }, RangeError);

if (typeof reportCompare === "function")

  reportCompare(true, true);