date-with-offset/test/constructor_test.js

Work with timezone-aware dates

var assert = require("assert"),
    DateWithOffset = require('../');

describe('new DateWithOffset', function() {

  it('requires at least one argument', function() {
    assert.throws(
      function() {
        new DateWithOffset();
      },
      TypeError
    );
  });

  it('requires an offset that can be converted to a Number', function() {
    assert.throws(
      function() {
        new DateWithOffset('foo');
      },
      TypeError
    );
  });

  it('accepts a number offset', function() {
    assert.doesNotThrow(function() {
      new DateWithOffset(-400);
    });
  });

  it('accepts an offset that responds to valueOf', function() {
    var offset = { valueOf: function() { return 240; } };
    assert.doesNotThrow(function() {
      new DateWithOffset(offset);
    });
  });

  describe('with a Date and an offset', function() {
    it('returns the same moment in time in the given offset', function() {
      var date    = new Date("2008-11-22T12:00:00Z"),
          inTokyo = new DateWithOffset(date, 540);
      assert.equal(inTokyo.getTime(), date.getTime());
      assert.equal(inTokyo.getHours(), 21);
    });
  });

  describe('with a timestamp and an offset', function() {
    it('returns the same moment in time in the given offset', function() {
      var timestamp = (new Date("2008-11-22T12:00:00Z")).getTime(),
          inTokyo   = new DateWithOffset(timestamp, 540);
      assert.equal(inTokyo.getTime(), timestamp);
      assert.equal(inTokyo.getHours(), 21);
    });
  });

  describe('with a GMT date string and an offset', function() {
    it('returns the same moment in time in the given offset', function() {
      var isoString = "2008-11-22T12:00:00.000Z",
          inTokyo   = new DateWithOffset(isoString, 540);
      assert.equal(inTokyo.toISOString(), isoString);
      assert.equal(inTokyo.getHours(), 21);
    });
  });

  describe('with a local date string and an offset', function() {
    it('treats the time as local to the given offset', function() {
      var inTokyo = new DateWithOffset('Nov 22 2008 21:00:00', 540);
      assert.equal(inTokyo.toISOString(), '2008-11-22T12:00:00.000Z');
      assert.equal(inTokyo.getHours(), 21);
    });
  });

  describe('with year, month, day, hours, minutes, and an offset', function() {
    it('treats the time as local to the given offset', function() {
      var inTokyo = new DateWithOffset(2008, 10, 22, 21, 0, 540);
      assert.equal(inTokyo.toISOString(), '2008-11-22T12:00:00.000Z');
      assert.equal(inTokyo.getHours(), 21);
    });
  });

});