public void ConfirmRemovingPrigAssembly_should_show_the_message_to_message_box( [Values(VSConstants.MessageBoxResult.IDYES, VSConstants.MessageBoxResult.IDNO)] VSConstants.MessageBoxResult response) { // Arrange var fixture = new Fixture().Customize(new AutoMoqCustomization()); var deletionalInclude = fixture.Create <string>(); var vm = new PrigViewModel(); vm.MessageBoxParameter.Subscribe(_ => _.Result = response); // Act var result = vm.ConfirmRemovingPrigAssembly(deletionalInclude); // Assert Assert.AreEqual(response == VSConstants.MessageBoxResult.IDYES, result); var msgBox = vm.MessageBoxParameter.Value; Assert.AreEqual(OLEMSGBUTTON.OLEMSGBUTTON_YESNO, msgBox.Button); Assert.AreEqual(OLEMSGICON.OLEMSGICON_QUERY, msgBox.Icon); Assert.IsNotNullOrEmpty(msgBox.Text); }