public void MapperDoesNotNotifyDettachedObservers()
        {
            var airspace  = Substitute.For <SWT_ATM.IObserver <List <Data> > >();
            var format    = new TransponderDataFormat();
            var mapper    = new CoordinateMapper(format);
            var simulator = new TrackSimulator(mapper, Substitute.For <ITransponderReceiver>());

            mapper.Attach(airspace);
            mapper.Deattach(airspace);

            var testData = new List <string>();

            testData.Add("ATR423;39045;12932;14000;20151006213456789");

            simulator.OnDataReceieved(null, new RawTransponderDataEventArgs(testData));

            airspace.DidNotReceive().Update(Arg.Any <List <Data> >());
        }