Revisiting CSV Data Binding in VS2008 Coded Web Tests

I've been going through the WinDBG labs located here. Tess has done a great job with the labs and done all the hard work, so w00t for her!

I needed to add another .CSV data file for my main VUser that I am currently working on so I did a copypasta of a pre-existing DataBinding and DataSource. When I first created the coded web test I had added so much custom code that I deleted the web test and left only the coded web test. The fear was that I might accidently re-gen the code from the web test and over write my work. That in and of itself shouldn't be too bad since we all know to use a code repository, right? Of course we do.

Anyhoo, I made the code changes and was greeted by an error when my file couldn't be loaded. Huh? How rude!

I finally got it to work, but I wanted to note the way .CSV data binding works in a coded web test in greater detail just to remind myself next time this happens. There are plenty of examples of binding a .CSV file to a web test, but few on a pre-existing coded web test. So, here goes!

First we have to have a DataSource declaration that takes five parameters for a .CSV file:

1: dataSourceName
This is the name we are giving the DSN for our .CSV file.
2: providerName
In my case for a .CSV file I am using "Microsoft.VisualStudio.TestTools.DataSource.CSV"
3: connectionString.
For my use, this is the path with escaped back-whacks to the .CSV file. In my case, it is "c:\\data\\streetNames.csv"
4: DataBindingAccessMethod
For my use, I want a random selection of data from the .CSV file so I am using "Microsoft.VisualStudio.TestTools.WebTesting.DataBindingAccessMethod.Random"
5: tableName
I thought that I could provide my own table name to reference the .CSV file but that didn't work and was forced to use the form of #csv, like this: "streetNames#csv". When I tried to use the name "streetNameTable" I would get back an error of "cannot find streetTableName.txt" from VS2008. But, the #csv form works, so no biggie.

Here is what I am using for my entire Data Source:

   1:    [DataSource("streetNameDataSource",

   2:              "Microsoft.VisualStudio.TestTools.DataSource.CSV",

   3:              "C:\\Data\\streetNames.csv",

   4:              Microsoft.VisualStudio.TestTools.WebTesting.DataBindingAccessMethod.Random,

   5:              "streetNames#csv")]

Next, we have to define what column we are pulling from the .CSV file. In my case, it is a single column CSV file but we still have to have a column name defined. For my CSV file I am using the form of:

8<---------------------------
streetNames
"ABBINGTON"
"ALDRICH"
"ALEXANDER"
"ALICE"
"ALLISON"
"ALMOND"
"ALTA"
"AMHERST"
--------------------------->8

These are all the street names in Grover's Mill, NJ as reported by Melissa Data.

The DataBinding declaration that I am using takes four parameters.

1: dataSourceName
This is the DSN that we previously defined.
2: tableName
This is the tableName that we defined in the form of #csv.
3: columnName
This is the column name of the CSV that we are extracting. I've found this to be case insensitive.
4: contextVariableName
This is the key name of the entry that will be created in the Context for the iteration.

Here is what I am using for my DataBinding:

   1:    [DataBinding("streetNameDataSource", "streetNames#csv", "streetNames", "streetNames")]

Now with each iteration of the vuser I can reference the Context for the randomized street name, ala:

   1:  Debug.WriteLine("Street name is " + this.Context["streetNames"].ToString());

Works like a champ!