Test a button in C#

Question

I have the following buttons in C# and i should test their functionality for a university project, but i have no idea how to do that. Watched a few tutorials on Nunit and Xunit but they didnt explain how the buttons should be tested. Can someone please give an example on how i must a test code for these buttons?

 private void Savebtn_Click(object sender, EventArgs e)
    {
        if (PrNameTb.Text == "" || CatCb.SelectedIndex == -1 || QtyTb.Text == "" || PriceTb.Text == "")
        {
            MessageBox.Show("Missing Information");
        }
        else
        {
            try
            {
                Con.Open();
                SqlCommand cmd = new SqlCommand("insert into ProductTbl (PrName,PrCat,PrQty,PrPrice) values(@PN,@PC,@PQ,@PP)", Con);
                cmd.Parameters.AddWithValue("@PN", PrNameTb.Text);
                cmd.Parameters.AddWithValue("@PC", CatCb.SelectedItem.ToString());
                cmd.Parameters.AddWithValue("@PQ", QtyTb.Text);
                cmd.Parameters.AddWithValue("@PP", PriceTb.Text);
              
                cmd.ExecuteNonQuery();
                MessageBox.Show("Product Added");
                Con.Close();
                DisplayProducts();
                Clear();
            }
            catch (Exception Ex)
            { MessageBox.Show(Ex.Message); }
        }

    }



public void DeleteBtn_Click(object sender, EventArgs e)
    {
        if (Key == 0)
        {
            MessageBox.Show("Select an Product");
        }
        else
        {
            try
            {
                Con.Open();
                SqlCommand cmd = new SqlCommand("Delete from ProductTbl where PrId = @PKey", Con);
                cmd.Parameters.AddWithValue("@PKey", Key);

                cmd.ExecuteNonQuery();
                MessageBox.Show("Product Deleted");
                Con.Close();
                DisplayProducts();
                Clear();
            }
            catch (Exception Ex)
            { MessageBox.Show(Ex.Message); }
        }
    }