Add RecClientTestBase for integration testing setup

Introduce `RecClientTestBase` to streamline integration tests for `ReCClient`.
This abstract class uses `WebApplicationFactory` to create a test server
for `ReC.API` and configures a `ServiceProvider` with necessary services.
It includes helper methods for creating scoped `ReCClient` instances and
ensures proper resource cleanup via `IDisposable`.

Update `ReC.Tests.csproj` to include:
- `Microsoft.AspNetCore.Mvc.Testing` package for integration testing.
- Project references to `ReC.API` and `ReC.Client` for testing purposes.

These changes establish a reusable and maintainable testing infrastructure.

tests/ReC.Tests/Client/RecClientTestBase.cs

@@ -0,0 +1,75 @@
+using System;
+using System.IO;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Mvc.Testing;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using ReC.Client;
+
+namespace ReC.Tests.Client;
+
+public abstract class RecClientTestBase : IDisposable
+{
+    private readonly WebApplicationFactory<Program> _factory;
+    private readonly ServiceProvider _serviceProvider;
+
+    protected RecClientTestBase()
+    {
+        var apiContentRoot = LocateApiContentRoot();
+
+        _factory = new WebApplicationFactory<Program>()
+            .WithWebHostBuilder(builder =>
+            {
+                builder.UseEnvironment("Development");
+                builder.UseContentRoot(apiContentRoot);
+            });
+
+        _ = _factory.CreateClient();
+
+        var services = new ServiceCollection();
+        services.AddLogging();
+        services.AddSingleton(_factory.Services.GetRequiredService<IConfiguration>());
+
+        services.AddRecClient(client =>
+        {
+            client.BaseAddress = new Uri("http://localhost");
+        });
+
+        services.AddHttpClient(ReCClient.ClientName)
+            .ConfigurePrimaryHttpMessageHandler(() => _factory.Server.CreateHandler());
+
+        _serviceProvider = services.BuildServiceProvider();
+    }
+
+    protected IServiceProvider ServiceProvider => _serviceProvider;
+
+    protected IConfiguration Configuration => _factory.Services.GetRequiredService<IConfiguration>();
+
+    protected (ReCClient Client, IServiceScope Scope) CreateScopedClient()
+    {
+        var scope = _serviceProvider.CreateScope();
+        var client = scope.ServiceProvider.GetRequiredService<ReCClient>();
+        return (client, scope);
+    }
+
+    public void Dispose()
+    {
+        _serviceProvider.Dispose();
+        _factory.Dispose();
+    }
+
+    private static string LocateApiContentRoot()
+    {
+        var current = new DirectoryInfo(AppContext.BaseDirectory);
+        while (current is not null)
+        {
+            var candidate = Path.Combine(current.FullName, "src", "ReC.API");
+            if (File.Exists(Path.Combine(candidate, "appsettings.json")))
+                return candidate;
+
+            current = current.Parent;
+        }
+
+        throw new DirectoryNotFoundException("Could not locate src/ReC.API content root from the test base directory.");
+    }
+}

tests/ReC.Tests/ReC.Tests.csproj

@@ -12,6 +12,7 @@
   <ItemGroup>
     <PackageReference Include="coverlet.collector" Version="6.0.0" />
     <PackageReference Include="MediatR" Version="14.0.0" />
+    <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="8.0.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
     <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="10.0.0" />
     <PackageReference Include="Moq" Version="4.20.72" />
@@ -21,7 +22,9 @@
   </ItemGroup>
 
   <ItemGroup>
+    <ProjectReference Include="..\..\src\ReC.API\ReC.API.csproj" />
     <ProjectReference Include="..\..\src\ReC.Application\ReC.Application.csproj" />
+    <ProjectReference Include="..\..\src\ReC.Client\ReC.Client.csproj" />
     <ProjectReference Include="..\..\src\ReC.Infrastructure\ReC.Infrastructure.csproj" />
     <ProjectReference Include="..\..\src\ReC.Domain\ReC.Domain.csproj" />
   </ItemGroup>