public NavigationViewModelTests()
        {
            Mock <INavigationDataProvider> navigationDataProviderMock = new Mock <INavigationDataProvider>();

            navigationDataProviderMock.Setup(provider => provider.GetAllFriends())
            .Returns(() => new List <LookupItem>()
            {
                new LookupItem()
                {
                    Id = 1, DisplayMember = "Manas Bajaj"
                },
                new LookupItem()
                {
                    Id = 2, DisplayMember = "Gautam Bajaj"
                },
            });
            eventAggregatorMock = new Mock <IEventAggregator>();
            eventAggregatorMock.Setup(aggregator => aggregator.GetEvent <OnDeleteFriendEvent>())
            .Returns(new OnDeleteFriendEvent());
            onDeleteFriendEvent = eventAggregatorMock.Object.GetEvent <OnDeleteFriendEvent>();
            eventAggregatorMock.Setup(aggregator => aggregator.GetEvent <OnFriendSavedEvent>())
            .Returns(new OnFriendSavedEvent());
            onFriendSavedEvent = eventAggregatorMock.Object.GetEvent <OnFriendSavedEvent>();

            viewModel = new NavigationViewModel(navigationDataProviderMock.Object, eventAggregatorMock.Object);
        }
        public MainViewModelTests()
        {
            navigationViewModelMock = new Mock <INavigationViewModel>();
            eventAggregatorMock     = new Mock <IEventAggregator>();
            eventAggregatorMock.Setup(aggregator => aggregator.GetEvent <OpenFriendEditViewEvent>())
            .Returns(new OpenFriendEditViewEvent());
            eventAggregatorMock.Setup(aggregator => aggregator.GetEvent <OnDeleteFriendEvent>())
            .Returns(new OnDeleteFriendEvent());
            openFriendEditViewEvent = eventAggregatorMock.Object.GetEvent <OpenFriendEditViewEvent>();
            onDeleteFriendEvent     = eventAggregatorMock.Object.GetEvent <OnDeleteFriendEvent>();

            mainViewModel = new MainViewModel(navigationViewModelMock.Object, CreateFriendEditViewModel,
                                              eventAggregatorMock.Object);
        }