title: Xcode unittest build failed with error "Undefined symbols for architecture x86_64"
body: <p>My unittest target build failed with below error:</p>
  
  <pre><code>Undefined symbols for architecture x86_64:
    "_OBJC_CLASS_$_MCStore", referenced from:
        objc-class-ref in MCStoreTests.o
  ld: symbol(s) not found for architecture x86_64
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  </code></pre>
  
  <p>Basic information:</p>
  
  <ul>
  <li>Xcode6.2</li>
  <li>iOS8.2 SDK</li>
  </ul>
  
  <p>What I have checked:</p>
  
  <ul>
  <li><code>Symbols Hidden by Default</code> is No</li>
  <li><code>Other Linker Flags</code> is -framework XCTest</li>
  <li><code>Framework Search Paths</code> is $(SDKROOT)/Developer/Library/Frameworks $(inherited)</li>
  </ul>