In addition to my JUnit-based unit tests, I have some (hand-written) quick &
dirty performance tests.   These take the form of an executable java class (with
void main(String[] argc) method which just run the old & new versions of some of
my code classes, and time how long they each take to complete.  Since these are
test utility classes rather than the code I'm building, I put them under "Test
Packages" rather than "Source Packages" in my (General|Java Class Library)
project.  However, when I try to run them with Shift+F6, I just get a
junit.framework.AssertionFailedError telling me there's "No tests found".

I don't want it to try to run the class with JUnit - I named it *Timer rather
than *Test and it doesn't extend TestCase, in order to avoid this.  However,
Netbeans doesn't appear to take this into account when Executing the class.  If
I cut & paste the class into the equivalent package under "Source Packages",
Shift+F6 runs it as expected.  However, it then gets included in the built JAR
File.  I suppose I could just configure a specific Exclude entry in the project
properties to avoid this, but IMO the class doesn't really belong under Source,
as it's only for testing.