title: Link error while building a unit test target
body: <p>I have a XCode4 / iOS project with a regular target and unit test target. Everything works fine, except when I try to #import one of my classes in my test class and try to use it. If I try to build the unit test target, I get the following link error:</p>
  
  <pre><code>Undefined symbols for architecture i386:
    "_OBJC_CLASS_$_FRRCategory", referenced from:
        objc-class-ref in CategoryTests.o
  ld: symbol(s) not found for architecture i386
  collect2: ld returned 1 exit status
  </code></pre>
  
  <p>In CategoryTests.m I'm importing the header file in this way:</p>
  
  <pre><code>#import "../todoro/FRRCategory.h"
  </code></pre>
  
  <p>What am I doing wrong?</p>