private void btnAddTest_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                bl.addTest(t);
            }

            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
        private void btnAddTest_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                bl.addTest(MyTest);
                MessageBox.Show("You have successfully added a test");
            }

            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }