public void Archive_AppendEntry() { //Arrange string archive = AvailableFiles.First(x => x.Name == "Archived.zip").FullName; var input = new FileInfo(Path.Combine(CurrentDirectory.FullName, "Append.zip")); File.Copy(archive, input.FullName, true); var ntick1 = new Tick(new TickerSymbol("Testing", "Testing", CurrencyType.AUD), DataSource.IEX) { TimeZone = TimeZone.Utc, AskSize = 12, AskPrice = 123.1231m, AskSource = DataSource.Binance, BidSize = 231213, BidPrice = 1231.123123m, BidSource = DataSource.Binance, DataType = DataType.Tick, Depth = 0, EndTime = DateTime.MaxValue, IsBackfilling = false, Occured = DateTime.MaxValue, Price = 12313.123123m, Size = 12313, Source = DataSource.Binance, TradePrice = 123123.1231m }; var currentcount = Archive.GetEntries(input.FullName).Count; //Act var result = Archive.Append(input.FullName, "Testing.DAT", LZ4MessagePackSerializer.Serialize(ntick1)); //Assert result.Should().BeTrue(); Archive.GetEntries(input.FullName).Count.Should().BeGreaterThan(currentcount); Archive.GetEntries(input.FullName).Should().ContainKey("Testing.DAT"); }