Public Property WorkingDirectory As String

public string WorkingDirectory {get; set;}

using (TempDirectory dir = new TempDirectory())
using (ScriptRunner runner = new ScriptRunner(ScriptEngine.Language.Cmd, "@ECHO cd"))
{
    string output = String.Empty;
    runner.OutputReceived += delegate(object o, ProcessOutputEventArgs e) { output += e.Data; };

    Assert.AreNotEqual(dir.TempPath, runner.WorkingDirectory);
    runner.WorkingDirectory = dir.TempPath;
    Assert.AreEqual(dir.TempPath, runner.WorkingDirectory);
    runner.Run();
    Assert.AreEqual(dir.TempPath.TrimEnd('\\', '/'), output.TrimEnd('\\', '/'));
}

Using dir As New TempDirectory()
    Using runner As New ScriptRunner(ScriptEngine.Language.Cmd, "@ECHO cd")
        Dim output As String = [String].Empty
        runner.OutputReceived += Function(o As Object, e As ProcessOutputEventArgs) Do
            output += e.Data
        End Function

        Assert.AreNotEqual(dir.TempPath, runner.WorkingDirectory)
        runner.WorkingDirectory = dir.TempPath
        Assert.AreEqual(dir.TempPath, runner.WorkingDirectory)
        runner.Run()
        Assert.AreEqual(dir.TempPath.TrimEnd("\"C, "/"C), output.TrimEnd("\"C, "/"C))
    End Using
End Using