public void TestValidDateTime()
{
DateService ds = new DateService();
string s = ds.DateTimeToString(new DateTime(1970, 1, 1));
Assert.Equal("1970-01-01", s);
}
public void TestInalidDateTime()
{
DateService ds = new DateService();
Assert.Throws <ArgumentOutOfRangeException>(() => ds.DateTimeToString(new DateTime(1970, 13, 1)));
}
public void Test29February2021_ThrowsRangeExeception()
{
DateService ds = new DateService();
Assert.Throws <ArgumentOutOfRangeException>(() => ds.DateTimeToString(new DateTime(2021, 02, 29)));
}