public void VoorlettersVanNamenMetR_selecteertAlleenNamenMetrOFR()
        {
            var target = new NamenManager(new List <string> {
                "Jan", "Marco", "Rouke"
            });

            IEnumerable <char> result = target.VoorlettersVanNamenMetR();

            List <char> expected = new List <char> {
                'M', 'R'
            };

            CollectionAssert.AreEqual(expected, result.ToList());
        }
        public void VoorlettersVanNamenMetR_produceert_Voorletters()
        {
            var target = new NamenManager(new List <string> {
                "Marco", "Lars"
            });

            IEnumerable <char> result = target.VoorlettersVanNamenMetR();

            List <char> expected = new List <char> {
                'M', 'L'
            };

            CollectionAssert.AreEqual(expected, result.ToList());
        }