I am using Visual Studio C# 2008 Express Edition. I have a solutions with two projects, one is the main program itself, another one is an nunit test project.
I want each project to build to different paths, so physical test fixtures will not appear in the release folder. I opened up the project properties’s build tab, and specified the test_project’s “output to” to be bin\Test\. The main_project’s output path is set to be bin\Release\.

Now when I build, all the output files goes to the bin/Test folder, and the bin/Release folder is never touched. I even deleted the contents in the release folder, but building will not recreate the output files in the release folder.
Am I doing something wrong?
There are a few concepts here – Main project vs Test and Debug vs Release mode and finally Deployment
Where is code compiled to?
A project’s output will by default go under the project structure under bin\Debug. There’s no need to change it usually.
So the main project output would go to MainProject\bin\debug and the test project to TestProject\bin\debug. Within the TestProject bin\debug you’d get copies of the MainProject files because they are referenced by the TestProject.
Release version and other Build configurations
If you want to build a Release version of your code (without the pdb files) then you need to change the Build Configuration – at the top of VS you should see a dropdown that says Debug (currently) – this is why its building to Debug. You can also see this within the project properties – Build – Configuration: Active(Debug). This is nothing to do with whether its a Main Project/Test whatever. In each configuration (see Build – Configuration Manager) you specify the projects that you want to include – obviously normally you don’t include an NUnit Test project in a Release output but there’s nothing to stop you doing it)
Deployment
Then you get to the bigger picture question about what you’re actually deploying – this depends on how you’re deploying it – if just copying files then obviously you just want to look at one of the folders under the main project. If producing an installer then you select the main project output (and not the test project) as things to deploy.