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benerdin/TimeZoneConverter.cs

Last active August 29, 2015 14:04
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TimeZoneConverter
Raw
TimeZoneConverter.cs
using System;
using System.Linq;
namespace TimeZones
{
/// <summary>
/// Responsible for converting between different time zones.
/// </summary>
public class TimeZoneConverter
{
/// <summary>
/// Instantiates a converter for the current time zone.
/// </summary>
public TimeZoneConverter()
: this(TimeZone.CurrentTimeZone.StandardName)
{ }
/// <summary>
/// Instantiates a converter for the specified <paramref name="baseTimeZoneId"/>.
/// </summary>
/// <param name="baseTimeZoneId">The ID of the base time zone (e.g. &quot;Eastern Stnadard Time&quot;).</param>
public TimeZoneConverter(string baseTimeZoneId)
{
// Retrieve the system time zones.
var timeZones = TimeZoneInfo.GetSystemTimeZones();
// Attempt to set the base time zone.
_baseTimeZone = timeZones.FirstOrDefault(
tz => tz.Id.Equals(baseTimeZoneId, StringComparison.OrdinalIgnoreCase));
if (_baseTimeZone == null)
{
// Let the caller know that what they did is invalid.
throw new InvalidOperationException(
string.Format("You attempted to construct a TimeZoneConverter with an invalid time zone: {0}",
baseTimeZoneId)
);
}
// Remember some standard time zones.
_easternStandardTime = timeZones.First(
tz => tz.Id.Equals(EasternStandardTime, StringComparison.OrdinalIgnoreCase));
_pacificStandardTime = timeZones.First(
tz => tz.Id.Equals(PacificStandardTime, StringComparison.OrdinalIgnoreCase));
_koreaStandardTime = timeZones.First(
tz => tz.Id.Equals(KoreaStandardTime, StringComparison.OrdinalIgnoreCase));
}
/// <summary>
/// Convert the given <paramref name="dateTime"/> to Pacific Standard Time.
/// </summary>
/// <param name="dateTime">The DateTime to convert.</param>
/// <returns>A DateTime.</returns>
public DateTime ConvertToPacificStandardTime(DateTime dateTime)
{
return TimeZoneInfo.ConvertTime(
dateTime,
_baseTimeZone,
_pacificStandardTime);
}
/// <summary>
/// Convert the given <paramref name="dateTime"/> to Eastern Standard Time.
/// </summary>
/// <param name="dateTime">The DateTime to convert.</param>
/// <returns>A DateTime.</returns>
public DateTime ConvertToEasternStandardTime(DateTime dateTime)
{
return TimeZoneInfo.ConvertTime(
dateTime,
_baseTimeZone,
_easternStandardTime);
}
/// <summary>
/// Convert the given <paramref name="dateTime"/> to Korea Standard Time.
/// </summary>
/// <param name="dateTime">The DateTime to convert.</param>
/// <returns>A DateTime.</returns>
public DateTime ConvertToKoreaStandardTime(DateTime dateTime)
{
return TimeZoneInfo.ConvertTime(
dateTime,
_baseTimeZone,
_koreaStandardTime);
}
/// <summary>
/// The time zone ID for Easter Standard Time.
/// </summary>
public const string EasternStandardTime = "Eastern Standard Time";
/// <summary>
/// The time zone ID for Central America Standard Time.
/// </summary>
public const string CentralTime = "Central America Standard Time";
/// <summary>
/// The time zone ID for Pacific Standard Time.
/// </summary>
public const string PacificStandardTime = "Pacific Standard Time";
/// <summary>
/// The time zone ID for Korea Standard Time.
/// </summary>
public const string KoreaStandardTime = "Korea Standard Time";
private readonly TimeZoneInfo _baseTimeZone,
_pacificStandardTime,
_easternStandardTime,
_koreaStandardTime;
}
}
Raw
WhenUsingTimeZoneConverter.cs
using System;
using NUnit.Framework;
namespace TimeZones.UnitTests
{
[TestFixture]
public class WhenUsingTimeZoneConverter
{
[Test]
public void EnsureAnInvalidBaseTimeZoneThrowsAnException()
{
Assert.Throws<InvalidOperationException>(
() => new TimeZoneConverter("Mercury"),
"You attempted to construct a TimeZoneConverter with an invalid time zone: Mercury");
}
[Test]
public void EnsureTimeConvertsToPacificStandardTime()
{
// Arrange
var sut = new TimeZoneConverter();
var noonEst = new DateTime(2014, 7, 25, 12, 0, 0);
var expected = new DateTime(2014, 7, 25, 9, 0, 0);
// Act
var actual = sut.ConvertToPacificStandardTime(noonEst);
// Assert
Assert.That(actual, Is.EqualTo(expected));
}
[Test]
public void EnsureConvertsToEasternStandardTime()
{
// Arrange
var sut = new TimeZoneConverter(TimeZoneConverter.PacificStandardTime);
var noonPst = new DateTime(2014, 7, 25, 12, 0, 0);
var expected = new DateTime(2014, 7, 25, 15, 0, 0);
// Act
var actual = sut.ConvertToEasternStandardTime(noonPst);
// Assert
Assert.That(actual, Is.EqualTo(expected));
}
[Test]
public void EnsureTimeConvertsToKoreanStandardTime()
{
// Arrange
var sut = new TimeZoneConverter();
var noonEst = new DateTime(2014, 7, 25, 9, 0, 0);
var expected = new DateTime(2014, 7, 25, 22, 0, 0);
// Act
var actual = sut.ConvertToKoreaStandardTime(noonEst);
// Assert
Assert.That(actual, Is.EqualTo(expected));
}
[Test]
public void EnsureTimeConvertsFromDallasToKoreaStandardTime()
{
// Arrange
var sut = new TimeZoneConverter(TimeZoneConverter.CentralTime);
var noonCentral = new DateTime(2014, 7, 25, 8, 0, 0);
var expected = new DateTime(2014, 7, 25, 23, 0, 0);
// Act
var actual = sut.ConvertToKoreaStandardTime(noonCentral);
// Assert
Assert.That(actual, Is.EqualTo(expected));
}
}
}
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