src/third_party/v8/test/intl/regress-9912.js

// Copyright 2019 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

let df = new Intl.DateTimeFormat("en");

// A modern date
let d1 = new Date(2019, 3, 4);
let d2 = new Date(2019, 4, 5);
assertEquals(df.format(d1), df.formatRange(d1, d1));
assertEquals(df.format(d2), df.formatRange(d2, d2));
assertEquals("4/4/2019 – 5/5/2019", df.formatRange(d1, d2));

// An old date just before the Julian / Gregorian switch
let d3 = new Date(1582, 8, 13);
let d4 = new Date(1582, 9, 14);
assertEquals(df.format(d3), df.formatRange(d3, d3));
assertEquals(df.format(d4), df.formatRange(d4, d4));
assertEquals("9/13/1582 – 10/14/1582", df.formatRange(d3, d4));

// An older date
let d5 = new Date(1000, 0, 1);
let d6 = new Date(1001, 1, 2);
assertEquals(df.format(d5), df.formatRange(d5, d5));
assertEquals(df.format(d6), df.formatRange(d6, d6));
assertEquals("1/1/1000 – 2/2/1001", df.formatRange(d5, d6));