public void Roundtrip()
    {
        foreach (ExpertiseLevel kind in (ExpertiseLevel[])Enum.GetValues(typeof(ExpertiseLevel)))
        {
            ExpertiseLevel?kind2 = ExpertiseLevelConverter.Parse(kind.ToString().ToLowerInvariant());
            Assert.AreEqual(kind, kind2);
            var kind3 = Enum.Parse(typeof(ExpertiseLevel), ((ExpertiseLevel?)kind).ToVcfString() ?? "", true);
            Assert.AreEqual(kind, kind3);
        }

        // Test auf null
        //Assert.AreEqual(null, ExpertiseLevelConverter.Parse(null));

        // Test auf nicht definiert
        Assert.AreEqual(null, ((ExpertiseLevel?)4711).ToVcfString());
    }
 public void ParseTest() => Assert.IsNull(ExpertiseLevelConverter.Parse("nichtvorhanden"));