public void TestGetPrivateData()
        {
            ChaincodeStub stub = new ChaincodeStub("myc", "txId", handler.Object, new List <ByteString>(), null);

            byte[] value = new byte[] { 0x10, 0x20, 0x30 };
            handler.Setup(a => a.GetStateAsync("myc", "txId", "testcoll", "key", token)).ReturnsAsync(ByteString.CopyFrom(value));
            CollectionAssert.AreEqual(stub.GetPrivateData("testcoll", "key"), value);
            try
            {
                stub.GetPrivateData(null, "key");
                Assert.Fail("Null collection check fails");
            }
            catch (ArgumentException)
            {
                //ignored
            }

            try
            {
                stub.GetPrivateData("", "key");
                Assert.Fail("Empty collection check fails");
            }
            catch (ArgumentException)
            {
                //ignored
            }
        }