从Xcode运行单元测试时，所有模拟器都通过了测试。 当运行CI bot（在外部OS X服务器上）时，所有构建都很好，但只有一个模拟器将通过测试而其他所有构建都失败。 所有模拟器都安装在OS X服务器上，并在OS X服务器上从Xcode运行测试，它自己也会传递给所有模拟器。
日志文件没有明确说明这里发生了什么。
2015-02-04 06:12:27.349 Testing on device: <DVTiPhoneSimulator: 0x7fa381c83460> {
SimDevice: SimDevice : Resizable iPad (291F00E2-1A85-47B4-81D6-F51431E53950) : state={ Shutdown } deviceType={ SimDeviceType : com.apple.CoreSimulator.SimDeviceType.Resizable-iPad } runtime={ SimRuntime : 8.1 (12B411) - com.apple.CoreSimulator.SimRuntime.iOS-8-1 }
}
2015-02-04 06:12:27.349 Initializing test infrastructure.
2015-02-04 06:12:37.987 Launch session started, setting a disallow-finish-token on the run operation.
2015-02-04 06:12:38.011 Adding console adaptor for test process.
2015-02-04 06:12:39.406 Creating the connection.
2015-02-04 06:12:39.406 Listening for proxy connection request from the test bundle (all platforms)
2015-02-04 06:12:39.406 Resuming the connection.
2015-02-04 06:12:39.406 Test connection requires daemon assistance.
2015-02-04 06:12:39.408 Checking test manager availability..., will wait up to 120s
2015-02-04 06:12:40.161 testmanagerd handled session request.
2015-02-04 06:12:40.161 Waiting for test process to check in..., will wait up to 120s
2015-02-04 06:12:44.828 Test operation failure: Unable to run app in Simulator
2015-02-04 06:12:44.828 _finishWithError:Error Domain=IDEUnitTestsOperationsObserverErrorDomain Code=3 "Unable to run app in Simulator" UserInfo=0x7fa384c0aaa0 {NSLocalizedDescription=Unable to run app in Simulator} didCancel: 1
有没有人遇到过相同的问题和解决方案？
我们正在运行最新版本的Xcode 6和OS X Server。