Console output disappears from test data class constructors and IAsyncInitializer

[thomhurst]

Problem Description

Console output (e.g., Console.WriteLine()) from test data class constructors and IAsyncInitializer.InitializeAsync() is not being captured and displayed in test results. This output disappears completely, making it difficult to debug or track progress during long-running initialization operations.

Code Example

public sealed class TestRabbitContainer : IAsyncInitializer
{
    public TestRabbitContainer()
    {
        Console.WriteLine("Constructor called"); // This output disappears
    }
    
    public async Task InitializeAsync() 
    {
        await _instance.StartAsync(); // Long-running operation
        Console.WriteLine("Initialization complete"); // This output also disappears
    }
}

// Usage in test
[ClassDataSource<TestRabbitContainer>(Shared = SharedType.PerTestSession)]
public required TestRabbitContainer TestRabbitContainer { get; init; }

Root Cause Analysis

Based on codebase investigation:

1. Context Availability Issue: StandardOutConsoleInterceptor.cs (line 14) redirects console output to:

   protected override TextWriter RedirectedOut => Context.Current.OutputWriter;

2. Timing Problem: Test data is constructed in ClassDataSources.Create() method before TestContext.Current is set. In TestCoordinator.cs (line 73):

   TestContext.Current = test.Context;

   This happens AFTER class data has already been created.

3. Data Construction Flow: The ClassDataSources.cs Create() method (lines 74-120) instantiates objects via Activator.CreateInstance() and initializes them, but at this point there's no TestContext available yet to capture output.

Expected vs Actual Behavior

• Expected: Console output from constructors and InitializeAsync() should be captured and displayed in test results or logs
• Actual: Output disappears because there's no TestContext to write to when these methods execute

Impact

This is particularly problematic for:

• Resource-heavy initialization (Docker containers, database setup, etc.)
• Debugging initialization issues
• Tracking progress of long-running setup operations
• Understanding why initialization is taking significant time

Workaround

None currently available. Output must be captured through alternative means (e.g., custom logging to files).

Related

Originally reported in discussion #3803