public void Test_signing()
        {
            NullSigner signer = NullSigner.Instance;

            signer.Sign((Transaction)null);
            signer.Sign((Keccak)null).Bytes.Should().HaveCount(64);
        }
        public void Test()
        {
            NullSigner signer = NullSigner.Instance;

            signer.Address.Should().Be(Address.Zero);
            signer.CanSign.Should().BeTrue();
        }