public void TestCanAddDeveloperCommand2()
        {
            ViewModelDevelopers givenViewModel = new ViewModelDevelopers(new ObservableCollection <Developer>());

            givenViewModel.LastName = "Doe";

            Assert.AreEqual(false, givenViewModel.AddDeveloperCommand.CanExecute(null));
        }
        public void TestAddDeveloperCommand()
        {
            ViewModelDevelopers givenViewModel = new ViewModelDevelopers(new ObservableCollection <Developer>());

            givenViewModel.FirstName = "John";
            givenViewModel.LastName  = "Doe";
            givenViewModel.AddDeveloperCommand.Execute(null);

            Assert.IsNotNull(givenViewModel.Developers);
        }