xcode - Calling xcodebuild from Swift command line tool fails -

i'm writing simple swift command line tool application automates of ios dev work. working except 1 thing - calling xcodebuild script.

my method looks this:

func runtest(devicename: string, os: string) {         killallsimulators()         let sdk = "iphonesimulator"         let destination = "platform=ios simulator,name=" + devicename + ",os=" + os         let arguments = ["-workspace", workspace, "-scheme", scheme, "-sdk", sdk, "-destination", destination, "test"]         executor.executecommand("xcodebuild", arguments: arguments)     } 

devicename equal "iphone 4s", os equal "9.0", workspace , scheme variables set.

my execute command has simple implementation:

func executecommand(command: string, arguments: [string]) -> nsstring?  {         _ = nsprocessinfo.processinfo().processidentifier         let pipe = nspipe()         let filehandle = pipe.filehandleforreading          let task = nstask()         task.launchpath = "/usr/bin/" + command         task.arguments = arguments         task.standardoutput = pipe          task.launch()         let data = filehandle.readdatatoendoffile()         filehandle.closefile()          return nsstring(data: data, encoding: nsutf8stringencoding)     } 

i got error test failed because cdtool cannot compile. thats weird because same script called terminal works..

any ideas?