I'm using XCode 6.2 and I have a project with several targets and with no tests.
I'm trying to include now XCTest for one of the targets. To do so, I add a new "Cocoa Touch Testing Bundle" and select the target that I want as a host.
When trying to launch the test with Cmd+U, the simulator launches, opens the app for some milliseconds and then it closes, launching this message:
IDEBundleInjection.c: Error 4 loading bundle '/Users/pepito/Library/Developer/Xcode/DerivedData/Flight-gpauuftblwwxtvevnylzllkypkjy/Build/Products/Debug-iphonesimulator/target Tests.xctest': The bundle “target Tests” couldn’t be loaded because its executable couldn’t be located.
When I check the folder specified there, there is a just the Info.plist file, but there is no executable.
I have tried adding a branch new app target, which added automatically tests for it. The same error happens there when trying to run the tests.
If I create tests for a target in a brand new XCode project, then it works fine.
I got this error today because I forgot to add sources to the "Compile Sources" build phase in my test target.
I finally managed to solve the problem. It was related to the compiler selected by default for the XCTest target. It had selected "Unsupported Compiler" and I changed to "Default compiler (Apple LLVM 6.1)" and it started working again.
In my case, target's iOS Deployment Target in Build Settings was lower than target device's version. Hope that helps someone.
来源：https://stackoverflow.com/questions/29662266/xctest-the-bundle-target-tests-couldn-t-be-loaded-because-its-executable-coul