public void TestDemoDateTimeProvider()
{
var utcNow = DateTime.UtcNow;
//Act
var provider1 = new DateTimeProvider(utcNow);
var iso8601_1st = provider1.GetIso8601Format();
var provider2 = new DateTimeProvider(iso8601_1st);
var iso8601_2nd = provider2.GetIso8601Format();
//Assert
Assert.Equal(utcNow, provider1.GetStoredDateTime(), TimeSpan.FromSeconds(0.001));
Assert.Equal(utcNow, provider2.GetStoredDateTime(), TimeSpan.FromSeconds(0.001));
Assert.Equal(iso8601_1st, iso8601_2nd);
}