title: “File not found”, “linker command failed with exit code 1” in Xcode 4.5.1
body: <p>Am developing an existing iOS application and I have to write unit test cases for this project. It is building and running in Simulator 6.0. <strong>Whenever I try to test the project, it is showing the error message below.</strong> Am not able to figure the exact error.</p>
  
  <pre class="lang-none prettyprint-override"><code>id: file not found: /Users/Yuva/Library/Developer/Xcode/DerivedData/FlyApp-aexukpgtbathuadgxlnm/Build/Products/Debug-iphonesimulator/FlyApp.app/FlyApp
  clag: error: linker command failed with exit code 1 (use -v to see invocation)
  </code></pre>
  
  <p>Could you please help me to solve this linker error and test the app?</p>