public void ValidHash()
        {
            var blockID  = new BlockID("foo");
            var actual   = blockID.Valid();
            var expected = true;

            Assert.Equal(expected, actual);
        }
        public void InvalidHash()
        {
            var blockID  = new BlockID("");
            var actual   = blockID.Valid();
            var expected = false;

            Assert.Equal(expected, actual);
        }