Xcode 5.0.2 dyld: Library not loaded: @rpath/XCTest.framework/Versions/A/XCTest
It looks like your main target is linking to XCTest.framework as well as your test target. It should only be linked to the main target.
1) Go to Project settings
2) Go to your apps main target -> other linker flags
3) remove '-framework XCTest'
4) make sure the 'other linker flags' field for your test target still contains '-framework XCTest'
I ran into this error by renaming my targets one of which was a testing target. After reading the other answers I realized that my Build Phases > Compile Sources was including test classes as compile sources for non-test targets which then tried to import the XCTest framework.
Removing the test classes from my regular target’s Compile Sources solved this for my case.
