public void NotNull_Null_Throws()
        {
            //Arrange
            string underTest = null;


            //Act
            var exception = Record.Exception(() => Guards.String(underTest, nameof(underTest))
                                             .NotNull());


            //Assert
            exception.Should().BeOfType <ArgumentException>();
        }
        public void Equals_NotEquals_Throws()
        {
            //Arrange
            string underTest = "NotEqualString";


            //Act
            var exception = Record.Exception(() => Guards.String(underTest, nameof(underTest))
                                             .Equal("AnotherString"));


            //Assert

            exception.Should().BeOfType <ArgumentException>();
        }