Grabbing the output sent to Console.Out from within a unit test?

c#, console, nunit, unit-testing

Solution

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.

Problem

I am building a unit test in C# with NUnit, and I'd like to test that the main program actually outputs the right output depending on the command line arguments. Is there a way from an NUnit test method that calls `Program.Main(...)` to grab everything written to `Console.Out` and `Console.Error` so that I can verify against it?

Original source