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?