From this answer I did some workaround https://stackoverflow.com/a/26031521/677596
for xcode 6.3 and below
You can also use launchd for running tests on the iOS simulator from a SSH session, either by crafting a LaunchAgent and manually loading / starting that, or by using "launchctl submit”.
Now after switching to xcode 6.4, this workaround is causing some transient issue when running tests:
2015-07-27 18:20:10.024 xcodebuild[82019:35808239] Metadata.framework [Error]: _MDAccessCopyClientPort failed retrying
2015-07-27 18:20:10.024 xcodebuild[82019:35810614] Metadata.framework [Error]: couldn't get the client port
Testing failed:
Test target VoyagerTests encountered an error (Test session exited(-1) without checking in. If you believe this error represents a bug, please attach the log file at /var/folders/zj/17v5xz0n44j10tnn0tzbq8380000gq/T/com.apple.dt.XCTest-status/Session-2015-07-27_18:20:02-vjq6dO.log)
But if I just run the tests without loading LaunchAgent, it works fine then. Has anyone experienced the same things? Does it mean Xcode6.4 has fixed this problem?
The issue you are referring to was an issue in Xcode 6.0 through Xcode 6.2.x. It was addressed in Xcode 6.3.
You are possibly encountering another bug with _MDAccessCopyClientPort, so I suggest you file a radar for that at http://bugreport.apple.com