You can redirect Console.In, Console.Out and Console.Error to custom StringWriters, like this
[TestMethod]
public void ValidateConsoleOutput()
{
using (StringWriter sw = new StringWriter())
{
Console.SetOut(sw);
ConsoleUser cu = new ConsoleUser();
cu.DoWork();
string expected = string.Format("Ploeh{0}", Environment.NewLine);
Assert.AreEqual<string>(expected, sw.ToString());
}
}
See this blog post for full details.