Monthly Archives: October 2008

First Steps with Unit Testing Walkthrough

 In this article I introduce through a walkthrough the basics of how to write a good well structured unit test. This post is the first of a series about Unit testing and TDD. I’ll not be doing TDD for now because I first want to start with the basics of creating well structured unit tests.  In later posts we will build on this to practice TDD. Therefor the tests of this first walkthrough will seem overly simple, but let’s crawls before we start running.
The details on how we should write tests vary with the programming framework & unit test framework. For this walkthrough I’ve choosen to implement  the tests and examples witrh C# and VSTS .Nevertheless the core principle of how to implement automated tests stays applicable in any technology.  If you desire to get the walkthroughs for NUnit or for other programming frameworks post a demand in this blog.  You can download the completed walkthrough project here.

 


public class Fleet : IDisposable
{
private List _planes { get; set; }

public Fleet()
{
this._planes = new List();
}

public Plane this[string index]
{
get
{
return this._planes.Find(p => p.Name == index);
}
}

public void Add(string name)
{
this._planes.Add(new Plane(name));
}


public int Count
{
get
{
return this._planes.Count;
}
}

public void Dispose()
{
this._planes = null;
}
}

public class Plane
{
public Plane(string name)
{
this.Name = name;
}

public int PlaneID { get; set; }
public string Name { get; set; }

}


Examine the code of Fleet and Plane. The Fleet class represents an aero fleet (a simple Model) this class is a sort of collection of planes. The fleet class contains a property “Count” that counts the number of planes in the fleet.
Create a new Test Project File, right click solution, add, new, Project, select C#, Test, name your Project:”FirstStepsTest”.
Launch all tests: Ctrl R,A or Test, Windows, Test View
VS should launch the TestMethod1 and it should pass.

 Replace the generated TestMethod() with the following test:

[TestMethod()]
public void NewFleet_WithNoPlanes_CountWillReturn0()
{
   //Setup
  Fleet fleet = new Fleet();

  //Execute
  int actual = fleet.Count;

  //Verify
  Assert.AreEqual(0, actual);
}

Run the test by right click on the test name and select “Run Test”.
The test above is a public method whose giving the attribute [TestMethod] the test class itself is been annotated with the attribute [TestClass]. This enable the testRunner of VSTS to retrieve all test methods.

Every test will always consist of 3 parts:
• The setup: to be able to test our SUT we’ve to put him in a certain state so it can be tested.
• The test execution: when our SUT is prepared to be test we can call the actual execution unit on our SUT.
• The verification: A test generally ends with the comparison on the expected results and the actual outcome of our execution.

The last part of our test uses an assertion method of our unit testing framework. Knowing what to assert about in your tests is pretty much 90% of the battle. An assertion is basically taking an expected value and comparing it to an actual value. If the expected value does not match the actual value, then the test will fail.

There are many other type of assertions but for simplicity and for readability when debuging I prefer to only use the Assert.Equals(). Assert equals is the most generic form of assertion and it will always display a meaningful message like Assert.AreEqual failed. Expected:. Actual:.Add following new tests to the test class:

 


[TestMethod()]
public void Add_OnePlane_WillIncrementCountByOne()
{
//Setup
Fleet fleet = new Fleet();

//Execute
fleet.Add("X2938");

//Verify
Assert.AreEqual(1, fleet.Count);
}

[TestMethod()]
public void RetriveByIndex_APlane_WillReturnThePlane()
{
//Setup
Fleet fleet = new Fleet();
fleet.Add("X2938");

//Execute
String actual = fleet["X2938"].Name;

//Verify
Assert.AreEqual("X2938", actual);
}

Examine the tests and run them, they should all pass.

We’ll refactor a little bit our code because the test contains some parts of code that are repeated and repeating ourselves is always bad!
First we will remove the magic string: “X2938” and will instantiate a string field flightName containing this value. Replace “X238” with this new variable.
We will also promote the fleet object in each test to a new private field. We will use the [TestInitialize] attribute to instantiate this field.
Also imagine that our Fleet class implements IDisposable because it uses somehow an expensive resource that isn’t automatically disposed by the garbage collector. We could call fleet.Dispose() after the Assertion but what if our test fails? The dispose method would never been called and the object will remain in memory.
The result should look like that:
 


[TestClass]
public class FleetTest
{
private Fleet fleet;
const string flightName = "X2938";

[TestInitialize()]
public void TestInitialize()
{
fleet = new Fleet();
} [TestCleanup()] public void TearDown() { fleet.Dispose(); }

[TestMethod()]
public void NewFleet_WithNoPlanes_CountWillReturn0()
{

//Execute
int actual = fleet.Count;

//Verify
Assert.AreEqual(0, actual);
}

[TestMethod()]
public void Add_OnePlane_WillIncrementCountByOne()
{

//Execute
fleet.Add(flightName);

//Verify
Assert.AreEqual(1, fleet.Count);
}

[TestMethod()]
public void RetriveByIndex_APlane_WillReturnThePlane()
{
//Setup
fleet.Add(flightName);

//Execute
String actual = fleet[flightName].Name;

//Verify
Assert.AreEqual(flightName, actual);
}
}

We’ve defined a SetUp() and TearDown() pair of methods. In major XUnit frameworks, these are used to create Fixtures. A Fixture is some resource all tests in a test case have in common and which sets the context of the test (the situation in which we’re testing), as well as other repetitive objects or resources.
VSTS uses the attributes [TestInitialize()] for the Setup, this part is run before each test and [TestCleanup()] for the teardown, run after each test.
Because each test must be isolated (cannot share information) these methods will tell the Framework to create our Fixture (a Fleet instance) before each test, and destroy it after. So each test gets a shiny new version to play with, free of anything a previous test may have done.

The test case above is a good small start and I hope you enjoyed this first walkthrough on unit testing, don’t hesitate to post some feedback!

 

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ASP.NET Web setup project walkthrough

 
 
This post contains a walkthrough that will help you understand the basic tasks to accomplish to create an MSI packages for deploying your web application. The walkthrough describes the most common scenario of deploying a web project.  We will create a standard Web setup project.  This project will generate as output an msi package that will create and configure the application IIS and copy the application’s file to a specific location on the server.   This walkthrough also describes how to modify the web.config file for providing a connectionstring or change any of the configuration sections. 
Because msi packages are mostly deployed by system engineers from the command line, this walkthrough will also pay attention on how to enable quiet installs and how to pass parameters to the installer from the command line.
 

1.     Create a “Hello World” web service

To be able to create a setup will need a sample project that will be deployed by the setup project.  So we create a new empty ASP.NET website application.
– File->new ->ASP.NET WebService
image001
 
Add  a Class library project to your solution.
– File->Add->Class Librrary
image003
 
 
Now we should have 2 projects inside our solution.
– Add a static method SayHello() to the class1.
image006 
 
 
 
Reference this class in your web service project:
– Add Reference-> Projects->SayHelloLibrary
 image007
 
 
 
– Change the code of the Hello world method to use the Library static method SayHello()
 image010
 
 
 
– Hit F5, your solution should compile. 
– Test the application through the invoke button of the test web page, you should see the following:
 image011
 
 

2.     Add a Web setup project

We will add the web setup deployment project to the solution.
– File->Add->New Project->Other Project Types->Web Setup Project
image013
 
 
Now our solution should look like this:
 image016
 
 
Now the real work begins, we will configure our web setup project to hold our content and our compiled assemblies.
  
 

3.     Add content and assemblies to your web setup project

 
First we will add the content of our web service project.  These are the asmx pages and the content of the APP_CODE folder.  They will be compiled by the host IIS server the first time the site will be hit.
 
Right click on the setup project->Add->Project output.
image018
 
 
 
A “Add project output Group” dialog box should appear.
image019
 
 
 
 
Because our Web setup project does not have any compiled assemblies as output we only can select “Content Files”.   
 image022
 
 
You should be in the file system view. If you don’t see the above screen.
–  right-click on the web project setup folder and choose view->File system.
Now we will add our web service application compiled assemblies. 
– Right-click again on the web-setup project and choose Add->Project Output and select the SayHelloLibrary project and click on “Primary Output”.
image025 
 
 
After we click on the ok button Visual studio has added the “Primary Output” to the root of the Web Application Folder. This will result in a compile error the first time we try to hit the application we deploy.
To correct this error we must move the “Primary output” to the Bin folder of our web application. 
– Simply drag & drop the “Primary Output” to the bin folder.
image027
image029 
 
 
Before we test our first installation package we’ve to compile it because Visual studio will not compile it as part of the solution. When we compile our project, visual studio will generate an msi file containing all parts of our application.
It’s time to test our first installation packet. 
– Select the setup project->richt-click->Install
image031 
 
 
 
The setup wizard pops-up, click next.
image033 
 
 
You can change the default value of the  Virtual directory textbox.  The default Virtual Directory is a property of your “Web application folder” available in the File system view.  Important: If you want to be able of passing the virtual directory as a parameter through the console for a quiet installation you should set this property to a blank field otherwise the msi package will overwrite a blank value with the value of the property.
When the installation is completed successfully the web service should be available on the your local IIS server under the path http://localhost/HelloWorldSetup/service.asmx
image035 
 
 
The application should also be visible in the “Add or Remove Programs” in the Windows Control Panel.
image037 
  
 
 
 

4. Adapt the connectionString property of the Web.Config file.
 
The web setup project wizard alow us to change common IIS settings through the File System view (View->File System) by changing the properties of the “Web Application Folder”. 

image039 
 
 
 
We can also add prerequisits of our solution (the .net framework2 is a standard prerequisit).
To adapt the connectionString property of our Web.Config file we will have to add custom code to our project that will edit the config file.  To be able to this type of actions during a setup we’ve to create custom actions.  Custom actions are code that is executed during the installation process.  Therefore we’ve to create a new ClassLibrary project. 
– Add a classlibrary project and name it HelloWorldCustomActions.
– Add following assemblys references: System.Configuration.dll,
image041
 
 
 
System.Configuration.Install.dll, System.Web.dll.
– Add a new class to MyCustomAction.cs your project that will be used during the installation of your project.    This class must inherit from “System.Configuration.Install.Installer” class and be annotated with the RunInstaller(True) attribute. using System;
using System;
using System.Collections.Generic;
using System.Text;
using System.Configuration.Install;
using System.ComponentModel; 
namespace HelloWorldCustomActions
{   
  [RunInstaller(true)]   
  publicclassMyCustomAction:Installer   
  {       
    publicoverridevoid Install(System.Collections.IDictionary stateSaver)       
    {            base.Install(stateSaver);       
    }   
 }

}

 
 
Now we need to create our custom action and associate it with our class.
First we need to add the output of the HelloWorldCustomActions assembly in our Setup project.
– Right-click “HelloWorldSetup” project->Add->Primary Output
image044 
 
 
– From the File System View move the “Primary output from HelloWorld actions” to the bin folder.
Now we will make sure that our code is executed as a custom action during the installation.
– Right-click the project folder->view->CustomActions.
The Custom action view should be displayed.
– Right-click on the install folder->Add Custom Action->select “Primary output from HelloWorldCustomActions (Active)”.
 
image046 
 
 
The web setup project wizard contains a form where the user must select the application site and the virtual directory. To be able to locate and change the web.config file of our application we need to read these parameters.  We can also pass these arguments by the command line and provide a targetdirectory. 
To be able to access these parameters we need to declare them in the “CustomActionData” property of our CustomAction: 
– Select your custom action->In the property window select “CustomActionData” Insert the following values:
/targetdir="[TARGETDIR]\" /targetvdir="[TARGETVDIR]" /targetsite="[TARGETSITE]" /targetconn="[EDITA1]"  /db="[DB]"
 
image048
 
 
 
We will now add a screen to our wizard that prompts the user for a connectionString. 
– Right click the project->View ->User Interface.
– Right click start-> Add Dialog
image050 
  
 
– Select Textboxes(A) and move it between “Installation Address” and “Confirm Installation”.
– Set the following properties:
 
image054 
 
Now we will code our custom action.
– First check you have following references in you CustomAction project.
image056 
  
 
– Set following using statements in your CustomAction class:
using System;
using System.Configuration;
using System.Configuration.Install;
using System.ComponentModel;
using System.Diagnostics;
using System.IO;
using System.DirectoryServices;
using System.Web.Configuration;
using System.Windows.Forms;

 
 

 
your install method should look like:
 
 publicoverridevoid Install(System.Collections.IDictionary stateSaver)       
{            base.Install(stateSaver);
              // Retrieve configuration settings            string targetSite = Context.Parameters["targetsite"];
            string targetVDir = Context.Parameters["targetvdir"];
            string targetDirectory = Context.Parameters["targetdir"];
string targetConnectionString = Context.Parameters["targetconn"];
            //if this is a quiet install //the connectionstring is passed as with a parameter named "db"
            if (targetConnectionString.Length < 1)                targetConnectionString = Context.Parameters["db"];
              if (targetConnectionString.Length < 1)thrownewInstallException("Please provide a connectionstring!");
              if (targetSite == null)thrownewInstallException("IIS Site Name Not Specified!");
              if (targetSite.StartsWith("/LM/"))                targetSite = targetSite.Substring(4);  ConfigureWebConfig(targetSite, targetVDir, targetConnectionString);
          } 
Add the ConfigureWebConfig method:
 void ConfigureWebConfig(string targetSite, string targetVDir, string targetConn)       
{            // Retrieve "Friendly Site Name" from IIS for TargetSite
            DirectoryEntry entry =                 newDirectoryEntry("IIS://LocalHost/" + targetSite);            string friendlySiteName =                 entry.Properties["ServerComment"].Value.ToString();
              // Open Application’s Web.Config            Configuration config =                 WebConfigurationManager.OpenWebConfiguration("/" + targetVDir, friendlySiteName);
              addConnectionStringAttribute(targetConn, config);            togleCompilationAttribute(config);
              // Persist web.config settings            config.Save();
 

        }

 
Method to add the connectionstring to your web.config:
privatestaticvoid addConnectionStringAttribute(string connectionStringValue, Configuration config)       
{            ConnectionStringSettings appDatabase = newConnectionStringSettings();
            appDatabase.Name = "db";            appDatabase.ConnectionString = connectionStringValue;
            appDatabase.ProviderName = "System.Data.SqlClient";
              config.ConnectionStrings.ConnectionStrings.Clear();
            config.ConnectionStrings.ConnectionStrings.Add(appDatabase);
 

        }

This method will set the compilation attribute to debug=false
privatestaticvoid togleCompilationAttribute(Configuration config)       

{            CompilationSection compilation;            compilation = config.GetSection("system.web/compilation") asCompilationSection;
              if (compilation != null)                compilation.Debug = !compilation.Debug;
           

        }
Now you can test your installation package. 
– Right-click Setup project->Install.

The second screen should ask for a connectionstring.

image061 
 
 
 
5.     Quiet install
 
When distributing a setup package you will mostly install the application through a quiet install.  Therefore you’ve to pass the parameter through the command line.   I experienced that the parameters you pass through the console are sometimes overwritten by the parameters you’ve added in your custom screens.  This is why I added a supplementary parameter “db” and don’t use the parameter “targetconn”.  The installer first checks if the parameter is empty.  This will be the case if you install the application through a quiet install. 
You will find this parameter in the CustomactionData property of the custom action:
/targetdir="[TARGETDIR]\" /targetvdir="[TARGETVDIR]" /targetsite="[TARGETSITE]" /targetconn="[EDITA1]"  /db="[DB]"
 The code that handles the parameter in the Install method:
if (targetConnectionString.Length < 1)
                targetConnectionString = Context.Parameters["db"];
You can launch the msi setup package with the folowing command line: (First navigate to the directory containing the builded release version of the msi)
>HelloWorldSetup.msi /qb targetvdir="HelloWorld" db="Test for connectionstring"
If you want to specify the target website you need to specify the website IIS metabase targetsite path.  This path mostly begins with “/LM/W3SVC/” followed by the site id. 
A trick to find the site id or to debug the setup application is to use the /l* option.  Launch the installer with the /l* option and follow the wizard.  The /l* will log all the parameters passed to the installation program.  After the installation completes you can retrieve website metabase path by searching for the “targetsite” in the log file.
>HelloWorldSetup.msi /l* log.txt
I hope this tutorial help you to understand the basics of creating a web setup project.  This type of setup will enable you creating testable and repeatable deployment scenarios.  It will also help our IT engineers to deploy web applications gracefully on production machines.
 
GVD

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