public void Test()
        {
            var application = new FakeApplicationContext();

            var blockchain = application.GetService <Blockchain>();
            var controller = new ChainController(blockchain);

            var response = controller.Index();

            var actual = ((List <Block>)response.Value).First().PreviousHash;

            Assert.NotNull(actual);
            Assert.Equal("7F83B1657FF1FC53B92DC18148A1D65DFC2D4B1FA3D677284ADDD200126D9069", actual);
        }