private async void _textChangedAsync()
 {
     await Task.Run(() => {
         Matches = (from haltestelle in _mapper.FindByName(SearchText)
                    select haltestelle).ToList();
     });
 }
        public void TestFindByName()
        {
            Assert.AreEqual(0, _mapperReal.FindByName("").Count);
            Assert.AreEqual(0, _mapperReal.FindByName(" ").Count);
            Assert.AreEqual(0, _mapperReal.FindByName("  ").Count);
            Assert.AreEqual(3, _mapperReal.FindByName("hauptbahnhof").Count);
            Assert.AreEqual(2, _mapperReal.FindByName("neustadt").Count);
            Assert.AreEqual(1, _mapperReal.FindByName("asd").Count);

            Assert.IsTrue(_mapperReal.FindByName("hauptbahnhof").Contains(hauptbahnhof));
            Assert.IsTrue(_mapperReal.FindByName("hauptbahnhof").Contains(hauptbahnhofOst));
        }