# IT:AD:Unit Testing/Automated:HowTo:Test N-Tier Apps #



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* See also:
    [[IT/AD/NConfig/]]


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<panel title="Summary"> 

Developing Automated Unit Tests for N-Tier apps is an order more complex than the creation of tests for 3 Tier apps.


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## Process ##

Creating *Automated **Unit** Tests* of application tier services is relatively straight forward. It's done by remembering that Unit Tests are *never* Integration Tests, and Mock any services required.

Creating *Automated **Integration** Tests* of application tier services is doable.

<WRAP tip>
the TestFixtureSetup or even TestSetup method has to create a new IoC Container before every test and invoke the application's boot strapping sequence, using a different ConnectionString and NConfig'ed settings..
</WRAP>

Creating *Automated **Unit** Tests* of the Presentation Tier's services is done via mocking.

Creating *Automated **Integration** Tests* of the Presentation Tier services -- which invoke the Application Tier's services using WCF or other cross-tier serialization protocol -- is much more complex.

<WRAP information>
The App.Front.Tests integration tests have to:
* Create two different IoC containers
* The back tier's application has to be hosted within a test apphost console.
* The back app has to have a ServiceHost for each service it is exposing.
* Have to open up ports for each service:
    * `netsh http add urlacl url=http://+:80/MyServiceUri user=DOMAIN\user`
* The front app has to start the back app.
    * Which will go through its startup sequence.
* The front app has to shut down the console when done (for next test run).
    * That part is actually hard to do. 
        * The console app can use a timer to shut itself down 60 seconds after its last call.



</WRAP>



## Resources ##