public void Format_Should_Return_DateTime_In_Universal_Format()
{
// Arrange
IDateTimeProvider dateTimeProvider = new UtcDateTimeProvider();
// Act
string output = dateTimeProvider.Format(DateTime.UtcNow);
// Assert
output.Should().MatchRegex(@"^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z$");
}