public void TestIndexOf_ByColumnName()
{
DataTable dt = DataProvider.CreateParentDataTable();
for (int i = 0; i < dt.Columns.Count; i++)
{
Assert.Equal(i, dt.Columns.IndexOf(dt.Columns[i].ColumnName));
}
DataColumn col = new DataColumn();
Assert.Equal(-1, dt.Columns.IndexOf("temp1"));
Assert.Equal(-1, dt.Columns.IndexOf((string)null));
}