public void HideEmptyColumnsTest()
        {
            using (var filteredDataGridView = new FilteredDataGridView())
            {
                var dt = UnitTestStatic.GetDataTable(100);
                filteredDataGridView.DataSource = dt;
                using (var frm = new Form())
                {
                    frm.Controls.Add(filteredDataGridView);
                    frm.Show();
                    var numCol = 0;
                    foreach (DataGridViewColumn col in filteredDataGridView.Columns)
                    {
                        if (col.Visible)
                        {
                            numCol++;
                        }
                    }
                    Assert.AreEqual(numCol, dt.Columns.Count);
                    filteredDataGridView.HideEmptyColumns();

                    numCol = 0;
                    foreach (DataGridViewColumn col in filteredDataGridView.Columns)
                    {
                        if (col.Visible)
                        {
                            numCol++;
                        }
                    }

                    Assert.AreEqual(numCol + 1, dt.Columns.Count);
                }
            }
        }
        public void HideEmptyColumnsTest()
        {
            using (var filteredDataGridView = new FilteredDataGridView())
            {
                var dt = UnitTestStatic.GetDataTable();
                filteredDataGridView.DataSource = dt;
                using (var frm = new Form())
                {
                    frm.Controls.Add(filteredDataGridView);
                    frm.Show();
                    var numCol = filteredDataGridView.Columns.Cast <DataGridViewColumn>().Count(col => col.Visible);
                    Assert.AreEqual(numCol, dt.Columns.Count);
                    filteredDataGridView.HideEmptyColumns();

                    numCol = filteredDataGridView.Columns.Cast <DataGridViewColumn>().Count(col => col.Visible);

                    Assert.AreEqual(numCol + 1, dt.Columns.Count);
                }
            }
        }