This is an attempt to showcase functional injection using Func in C# so as to facilitate SOLID SRP and IOC. Here I attempt to separate business CPU intensive algorithms from other functionalities like ReadWrite to disk. AsyncReadWrite to disk structurally uses Windows I/O ports without ANY any need for CPU threads.

You don't really need to have a console app to see if the code works or not. Infact Nunit-tests should suffice. I shall show you the steps as to how you can achive the tests right from code even if you have no visual studio installed or anything installed on a plain commodity pc. Infact I mostly work on mac and I do not have Visual Studio on my windows server.

1. Move to your local git repository directory or any directory (with git init) in console.

2. Clone repository.

    git clone https://github.com/arupalan/PortfolioStream
    cd PortfolioStream
   

3. Check path of msbuild reg.exe query "HKLM\SOFTWARE\Microsoft\MSBuild\ToolsVersions\4.0" /v MSBuildToolsPath

4. Now get all nuget packages nuget restore PortfolioStream.sln

5. Next build the app (Note the path of msbuild above incase its not available to you) msbuild PortfolioStream.sln

   cd TestPortfolioStream\bin\Debug
   nunit3-console TestPortfolioStream.dll
   
   You may see errors like below. But don't worry its doing its job as expected .... its just because the data.txt file was not there.
   Overall result: Failed                                            
   Test Count: 4, Passed: 1, Failed: 3, Inconclusive: 0, Skipped: 0  
   Failed Tests - Failures: 0, Errors: 3, Invalid: 0   
   
   after you have copied the data.txt file there you can run the tests again. You will also see the 3.txt and 4.txt
   copy ..\..\Data.txt
   nunit3-console TestPortfolioStream.dll
   
   Test Run Summary                                                     
   Overall result: Passed                                             
   Test Count: 4, Passed: 4, Failed: 0, Inconclusive: 0, Skipped: 0   
   Start time: 2016-07-01 13:11:40Z                                   
   End time: 2016-07-01 13:11:40Z                                   
   Duration: 0.165 seconds                                          

        [Test]
        public async Task CanOrderByTenorThenByPortfolio()
        {
            var portfolioParser = new PortfolioStream<TenorBucket>();
            var algo = new TenorParser();
            var result = await portfolioParser.ReadAsync(algo.ParseFunc,
                                    @"Data.txt",
                                    Encoding.ASCII);
            Assert.AreEqual(result.Count, 36);

            var orderedBuckets = result.OrderBy(t => t.Tenor).ThenBy(p => p.PortfolioId);

            await portfolioParser.WriteAsync(orderedBuckets, 
                @"3.txt",
                Encoding.ASCII,
                b => string.Format("{0},{1},{2}", b.TenorStr, b.PortfolioId, b.Value));
        }

        [Test]
        public async Task ReadAsyncThowsExceptionIfDataFileNotExist()
        {
            var portfolioParser = new PortfolioStream<TenorBucket>();
            var algo = new TenorParser();
            Assert.That( async () => await portfolioParser.ReadAsync(algo.ParseFunc,
                                    @"",
                                    Encoding.ASCII),
                                    Throws.TypeOf<FileNotFoundException>());
        }

• You can execute with switch -console to see the logs on console