NUnit global initialization – bad idea?

[SetUpFixture]

This is the attribute that marks a class that contains the one-time setup or teardown methods for all the test fixtures under a given namespace.

The SetUp method in a SetUpFixture is executed once before any of the fixtures contained in its namespace.
The TearDown method is executed once after all the fixtures have completed execution.

Assembly wide initialization. If you don’t put the class in any namespace, it will apply to all tests in the assembly.

eg.

// using statements

[SetUpFixture]
public class GlobalSetup {
  [SetUp]
  public void ShowSomeTrace() {
    Trace.WriteLine("It works..."); // won't actually trace
  }
}

http://www.nunit.org/index.php?p=setupFixture&r=2.4