RedirectedConsole.cs

public class RedirectedConsole : IDisposable
{
    readonly TextWriter outBefore;
    readonly TextWriter errBefore;
    readonly StringWriter console;

    public RedirectedConsole()
    {
        console = new StringWriter();
        outBefore = Console.Out;
        errBefore = Console.Error;
        Console.SetOut(console);
        Console.SetError(console);
    }

    public string Output
    {
        get { return console.ToString(); }
    }

    public void Dispose()
    {
        Console.SetOut(outBefore);
        Console.SetError(errBefore);
        console.Dispose();
    }
}