Visual Studio and Data Driven Unit Tests

Unit testing can be tedious when you have a battery of data to test against.  If you’re just testing against a small number of different data, then using Data Driven Unit Tests might be a bit overkill.  However, Data Driven Unit Tests gives you is a single location of data that can be used throughout your unit testing project.  Instead of modifying the data you typed in your unit test code, you can just modify it in your data file.  I used this MSDN entry as a starting point.

The method we’ll be testing is shown below.

Public Function SomeMethod(ByVal data As String) As Integer
   Return data.Length
End Function

You create the unit test for SomeMethod as usual.  Now what about our data file?  I’ll use an XML data file that just holds a few strings named test.xml.

<Samples>
    <Sample0>My Sample</Sample0>
    <Sample1>This is another sample</Sample1>
</Samples>

Now you have your simple data file.  To hook it into your unit test project, open up the Test List Editor in Visual Studio.  Find the test that you want to use test.xml with and click on that test.

In the Properties, find the Data Connection String entry and press the ellipses button.  This will bring up the New Test Data Source Wizard.

Select XML File and press Next to bring up the next screen.  Press the ellipses button and find test.xml.  This should fill in Table and Preview data for you.

Pressing Next will bring you to the final page of the wizard.  Highlight the table and press Finish.

You’ll see a dialog after the previous step.  Press Yes and Visual Studio will add test.xml to your unit test project.

If you look at your Data Connection String property, it should now point to test.xml within your unit test project.  The next step is using the data in your unit test.  Here’s a simple example of how to use your data.

<DataSource("Microsoft.VisualStudio.TestTools.DataSource.XML", "|DataDirectory|\test.xml", "Samples", DataAccessMethod.Sequential)> _
<DeploymentItem("TestProject1\test.xml")> _
<TestMethod()> _
Public Sub SomeMethodTest()
  Dim target As Form1 = New Form1
  Dim data As String = String.Empty

  Assert.IsTrue(target.SomeMethod(TestContext.DataRow("Sample0")) = TestContext.DataRow("Sample0").ToString.Length)
End Sub

The attributes for SomeMethodTest get automatically added when you add test.xml to your Data Connection String property.  The main point here is that TestContext.DataRow() is used to access your data.

One issue that I’ve run into was that I wanted to move my data into a sub folder called Data within my unit test project.  This will work, but the path to test.xml is a hard path.  Why does this matter?  I’m part of a team and having a hard path breaks the unit test since not all of our workspace paths are the same.  If you look at the Data Connection String property, you’ll notice that |DataDirectory| is at the beginning before the xml file location.  This transfers fine over different workspaces, however you’ll have to leave the data file where it gets inserted into the project by default.

TeamBuild and WiX

Have you ever run into this error using TeamBuild to build a WiX setup project?

light.exe : error LGHT0217: An unexpected external UI message was received: The Windows Installer Service could not be accessed. This can occur if you are running Windows in safe mode, or if the Windows Installer is not correctly installed. Contact your support personnel for assistance.

Done building project "Setup.wixproj" -- FAILED.

It seems this problem is rampant on Vista build machines.  The solution usually had something to do with the vbscript engine, but I’ve tried all of those solutions and we were still failing WiX builds.  Besides, we’re using XP for our build machines.

I decided to login to our build machine using our build service account and manually build the WiX project through the IDE.  The project compiled fine so I kicked off another build.  That didn’t fix anything.  I then decided to compile the project using devenv.exe from the command line.  That compiled fine, but I noticed an ICE## warning.  At first I didn’t think anything of it because after this second step, our builds started to work.

Greg, being the manager that he is, told me to repeat the steps on our other build machine to see if that was indeed the fix to our problem.  I was hopeful, but it didn’t seem to work on the other machine.  Then he said to reboot the original build machine and repeat the steps.  Again, I was hopeful, but it looked like the steps I took before wasn’t the solution.

Later on in the day I tried to login to our build machine again using our service account to repeat the steps from before.  Firing a build didn’t work again, but this time that ICE## warning really caught my eye.  I remembered that the WiX project property page had some settings for ICE validation:

Although the ICE## message being returned by the build process was a warning, it was causing our build to fail.  Checking Supress ICE validation was the key and we now have an automated build for our WiX setup project.

My Thoughts On Scrum (Part 1)

If you’ve been following Greg's Blog, you’d know that our team (and our whole development group for that matter) is now using the Scrum methodology for software development.  I think it’s natural for anyone to get excited or somewhat nervous when a change in day to day operations gets implemented. 

Some people thrive on a dynamic lifestyle while others can’t handle change very well.  For a software developer, the only things that are certain are death, taxes, and change.  Being thrown into something new shouldn’t make your world flip upside-down.

Before Scrum, our team didn’t have a distinctly defined system.  It was definitely iterative and agile, but there were no hard release dates and no administrative tasks associated with our development.  Our team is very customer focused, so transitioning to Scrum didn’t really change our mentality on what we delivered, just how we delivered it.

The hardest part for me when we transitioned to Scrum was the administrative tasks.  Updating statuses, work hours, and general commenting on work items was new to me (and I’m still learning to get used to it).  However, I do understand the importance of these tasks since our sprint burndown chart gives us a great visual representation of our status.

I was assigned to my own project before Scrum and I felt solely responsible for it. Now that we’re Scrumming and there are four of us are working on the same project, I feel a deeper sense of camaraderie.  There’s less sense of I and more of us. 

I think our first sprint is going very well and I’m very happy about what we’re going to give to our customers at the end of this sprint.  As we become more experienced with Scrum, I’ll share some more of my thoughts.