Watch2 NuGet Package

The Watch2 NuGet package extends the functionality of dotnet watch by adding features such as console clearing and delay handling. It outputs the same information as dotnet watch.

1. Wrapper Interfaces

To facilitate testing, it is necessary to wrap various process creation classes from .NET (e.g., Process => ProcessWrapper, ProcessStartInfo => ProcessStartInfoWrapper). This allows for the testing of process outputs. These wrappers are primarily interfaces that can be mocked and redirected to the main class.

Most of these wrappers can be generated automatically using a Roslyn Code Generator.

Rule of Thumb

If the main class you want to wrap contains properties, methods, or events that return or accept instances of another class, you should create a wrapper for that class as well.

Example 1

The Process class has a property StartInfo of type ProcessStartInfo. Therefore, a wrapper for ProcessStartInfo must be created.

Example 2

The Process class has an event OutputDataReceived of type DataReceivedEventArgs. Consequently, a wrapper for DataReceivedEventArgs is required.

2. Rocks and Waiting for an Async Call

When mocking an async method with Rocks, it is essential to wait for the async call to complete.

For example, you must wait for .WaitForExitAsync() to finish before checking the process output.

The Watch2 package passes all the command line arguments to the dotnet watch. So how can it have its own settings? Simple: by reading a watch.json file that is in the same folder where it is executing.

1. Testing
I was considering how to perform the testing, and there were two options:

Microsoft File Providers: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/file-providers?view=aspnetcore-8.0

TestableIO: https://github.com/TestableIO/System.IO.Abstractions

I thought that the second option (TestableIO) would be easier to use and more flexible. However, I do not need to test the creation of the file, but rather the content of the file. Therefore, I will use the first option (Microsoft File Providers).

2. Maintain JSON in Sync with C#
I need a solution to transform JSON to C# on the fly (i.e., at compile time). For this, a Roslyn Code Generator can be used. The rscgutils NuGet package will be helpful for this purpose.

Here is the relevant configuration in the project file:

<ItemGroup>
    <PackageReference Include="Microsoft.Extensions.FileProviders.Abstractions" Version="8.0.0" />
    <PackageReference Include="rscgutils" Version="2024.2000.2000" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
</ItemGroup>

<ItemGroup>
    <ProjectReference Include="..\Watch2_Interfaces\Watch2_Interfaces.csproj" />
</ItemGroup>
<ItemGroup>
	<AdditionalFiles Include="options.gen.json" />
</ItemGroup>

Code in Program.cs
The code in Program.cs will utilize the above configurations and packages. Here is an example of how it might look:

This example demonstrates how to read the watch.json file using the Microsoft File Providers package. The rscgutils package will handle the transformation of JSON to C# at compile time, ensuring that the JSON configuration is always in sync with the C# code.

So the code in program.cs will be:

//test
//args = ["run --no-hot-reload"];
//string folder = @"D:\gth\RSCG_Examples\v2\Generator";

//uncomment this line for production
string folder = Environment.CurrentDirectory;

var serviceCollection = new ServiceCollection();
ConfigureServices(serviceCollection, folder);

var serviceProvider = serviceCollection.BuildServiceProvider();

var console = serviceProvider.GetRequiredService<IConsoleWrapper>();
var processManager = serviceProvider.GetRequiredService<ProcessManager>();
var startInfo = serviceProvider.GetRequiredService<IProcessStartInfo>();

var fileOptions = serviceProvider.GetRequiredService<IOptionsReader>();
if(!fileOptions.ExistsFile())
{
    var file = Path.Combine(folder, "watch2.json");
    File.WriteAllText(file, MyAdditionalFiles.options_gen_json);    
}

await processManager.StartProcessAsync(args, console, startInfo);



void ConfigureServices(IServiceCollection services,string folder)
{
    services.AddSingleton<IFileProvider>(new PhysicalFileProvider(folder));
    services.AddSingleton<IOptionsReader, OptionsReader>();
    services.AddSingleton<Ioptions_gen_json>(it =>
    {
        var optionsReader = it.GetRequiredService<IOptionsReader>();
        return optionsReader.GetOptions() ?? options_gen_json.Empty;
    });
    services.AddSingleton<IConsoleWrapper, ConsoleWrapper>();
    services.AddSingleton<ProcessManager, ProcessManager>();
    services.AddSingleton<IProcessStartInfo>(provider => new ProcessStartInfoWrapper
    {
    FileName = "dotnet",
    Arguments = "watch " + string.Join(' ', args),
    WorkingDirectory = folder,
    RedirectStandardOutput = true,
    RedirectStandardInput = true,
    RedirectStandardError = true,
    UseShellExecute = false,
    CreateNoWindow = true
    });

    services.AddLogging(loggingBuilder =>
    {
        loggingBuilder.ClearProviders();
        loggingBuilder.SetMinimumLevel(LogLevel.Trace);
        loggingBuilder.AddNLog("nlog.config");
    });
    services.AddSingleton<ILogger<ProcessManager>, Logger<ProcessManager>>();
    services.AddSingleton<Func<IProcessStartInfo, IProcessWrapper>>(it => new ProcessWrapper(it));
}