Adding a mock Datatable in Unit Testing

Question

I am Unit Testing one of my functions. Here is my code:

public void TestLabels()
{

  //Step 1: Creating a mock table with columns exactly like in the real table.
  DataTable table = new DataTable();

  DataRow mydatarow;
  mydatarow = table.NewRow();

  //Step 2: Adding the row as same as the Real Data!

  mydatarow["Name"] = "Test";
  mydatarow["Address"] = "00000 ST.";
  mydatarow["ZipCode"] = "77665";
  mydatarow["Tracking#"] = "";

  table.Rows.Add(mydatarow);

  foreach (DataColumn column in table.Columns)
    Console.WriteLine(column.ColumnName);

  //Step 3: Call method we are testing.
  var updateTable = IceTechUPSClient.Instance.CreateLabels(table);

  foreach (DataRow row in updateTable.Rows)
  {
    var trackingNumber = row["Tracking#"].ToString();
    Assert.IsFalse(String.IsNullOrWhiteSpace(trackingNumber), "Expecting tracking number generated for every row!");
    Assert.IsTrue(File.Exists(trackingNumber + ".gif"));
  }

}

Now I am getting an error: Column 'Name' does not belong to table. As you can see I have specified column name "Name" here and also added that particular row. Then why I am getting this error? Any help?

Thanks!

Answer 1

You haven't set up your columns (unless you've missed out some code in your example).

You need to create the columns with the required names before you can access them like this:

var columnSpec = new DataColumn
                    {
                        DataType = typeof(string),
                        ColumnName = "Name"
                    };
this.table.Columns.Add(columnSpec);

When you read data from the database if you've set AutoGenerateColumns to true (the default) you don't need to do this explicitly as it's done for you behind the scenes.