Unit test project failing due to reference issues

I have a unit test to test one of my model classes and I get the follow error when I try building u开发者_开发百科nit test target:

"_OBJC_CLASS_$_NSMyClass", referenced from: objc-class-ref-to-NSMyClass in LogicTests.o ld: symbol(s) not found collect2: ld returned 1 exit status

I have setup my unit tests as Apple recommends i.e. separate targets.

Does anyone know what I am doing wrong?

Have you included the source under test (in addition to the test cases) in the test case target?