public void IsValid_CreatedDateNotTooOld_ReturnsTrue()
        {
            // Arrange
            var token = new AuthenticationTokenUnderTest("abc", DateTime.Now.AddMinutes(-AuthenticationToken.ValidForMinutes / 2));

            // Act
            bool result = token.IsValid();

            // Assert
            Assert.IsTrue(result);
        }
        public void IsValid_CreatedDateTooOld_ReturnsFalse()
        {
            // Arrange
            var token = new AuthenticationTokenUnderTest("abc", DateTime.Now.AddMinutes(-AuthenticationToken.ValidForMinutes*2));

            // Act
            bool result = token.IsValid();

            // Assert
            Assert.IsFalse(result);
        }