Xcode 9 - Test target X encountered an error (Unable to connect to Test Manager)

Question

I\'m trying to run some of my Unit Tests but it kept giving me error:

Showing Recent Issues
Test target X encountered an error (Unable to connect to test manager         


        

Answer 1

Simply restarting the device fixed this for me (iOS 11.3)

Answer 2

I resolved this issue by doing a hard restart of my device. For my iPhone 8, I followed these instructions from macrumors.com: Hard restart iPhone 8

Alternatively, if you're an libimobiledevice user you can use /usr/local/bin/idevicediagnostics restart from your mac's terminal.

Hope this helps

Answer 3

I restarted my iPhone 6 (iOS 11.2.6) in a normal way to resolve the same issue.