public void TestAddFileStream()
        {
            byte[] zippedBytes;

            var signingCertificates = TestdataLoader.ReadCertificatesForTest();

            using (var zipStream = new MemoryStream())
                using (var fileStream = File.OpenRead("small.pdf"))
                {
                    using (var asiceBuilder =
                               AsiceBuilder.Create(zipStream, MessageDigestAlgorithm.SHA256, signingCertificates))
                    {
                        asiceBuilder.Should().NotBeNull();

                        asiceBuilder.AddFile(fileStream).Should().NotBeNull().And.BeOfType <AsiceBuilder>();

                        var asiceArchive = asiceBuilder.Build();
                        asiceArchive.Should().NotBeNull();
                    }

                    zippedBytes = zipStream.ToArray();
                }

            LogFixture.GetLog <AsiceBuilderTest>().Info($"Created zip containing {zippedBytes.Length} bytes");
            zippedBytes.Should().HaveCountGreaterThan(0);

            using (var zipStream = new MemoryStream(zippedBytes))
                using (var zipArchive = new ZipArchive(zipStream, ZipArchiveMode.Read))
                {
                    zipArchive.Entries.Count.Should().Be(4);
                }
        }