public void ShouldOnlyBeThreeDots()
        {
            var          ip    = new IPv4();
            const string input = "172.16.254.1";
            const string fails = "172.16.254.1.2";

            Assert.True(ip.isIPv4Address(input));
            Assert.False(ip.isIPv4Address(fails));
        }
        public void AllNumbersMustBeBetween0And255()
        {
            var          ip    = new IPv4();
            const string input = "172.16.254.1";
            const string fails = "256.1.1.2";

            Assert.True(ip.isIPv4Address(input));
            Assert.False(ip.isIPv4Address(fails));
        }
        public void BoundsCheck()
        {
            var          ip    = new IPv4();
            const string input = "0.254.255.0";

            Assert.True(ip.isIPv4Address(input));
        }
        public void ShouldHaveFourNumbers()
        {
            var          ip    = new IPv4();
            const string input = ".16.254.1";

            Assert.False(ip.isIPv4Address(input));
        }