Date Time helper methods for getting the start/end date of the week/month/year. #datetime

Date Time Helpers.cs

[TestClass()]
public class DateTimeExtTests
{
    private const int CurrentYear = 2015;
    private const int CurrentMonth = 3;
    private const int CurrentDay = 4;

    private DateTime CurrentDate
    {
        get { return new DateTime(CurrentYear, CurrentMonth, CurrentDay); }
    }


    [TestMethod()]
    public void StartOfMonthTest()
    {
        var result = CurrentDate.StartOfMonth();

        result.Year.Should().Be(CurrentYear);
        result.Month.Should().Be(CurrentMonth);
        result.Day.Should().Be(1);
    }

    [TestMethod()]
    public void EndOfMonthTest()
    {
        var result = CurrentDate.EndOfMonth();

        result.Year.Should().Be(CurrentYear);
        result.Month.Should().Be(CurrentMonth);
        result.Day.Should().Be(31);
    }

    [TestMethod()]
    public void StartOfWeekTest()
    {
        var result = CurrentDate.StartOfWeek(DayOfWeek.Monday);

        result.Year.Should().Be(CurrentYear);
        result.Month.Should().Be(CurrentMonth);
        result.Day.Should().Be(2);
    }

    [TestMethod()]
    public void EndOfWeekTest()
    {
        var result = CurrentDate.EndOfWeek(DayOfWeek.Monday);

        result.Year.Should().Be(CurrentYear);
        result.Month.Should().Be(CurrentMonth);
        result.Day.Should().Be(8);
    }

    [TestMethod()]
    public void StartOfYearTest()
    {
        var result = CurrentDate.StartOfYear();

        result.Year.Should().Be(CurrentYear);
        result.Month.Should().Be(1);
        result.Day.Should().Be(1);
    }

    [TestMethod()]
    public void EndOfYearTest()
    {
        var result = CurrentDate.EndOfYear();

        result.Year.Should().Be(CurrentYear);
        result.Month.Should().Be(12);
        result.Day.Should().Be(31);
    }
}