Manual signing fails for xcode test with embedded library. Can it be decomposed?

I'm trying to run Facebook's WebDriverAgent, for testing on real devices: http://ift.tt/1O2eHgA.

Our admin isn't a fan of Apple's automatic signing, so we're trying manual. When I put

 xcodebuild -project WebDriverAgent.xcodeproj -scheme WebDriverAgentRunner -destination id='4xxx9' test DEVELOPMENT_TEAM=xxxx PROVISIONING_PROFILE=xxxxx

it says

Testing failed:
WebDriverAgentLib has conflicting provisioning settings. WebDriverAgentLib is automatically signed, but provisioning profile xxxx has been manually specified. Set the provisioning profile value to "Automatic" in the build settings editor, or switch to manual signing in the project editor.

I set manual signing on everything (in xcode), and try again:

xcodebuild -project WebDriverAgent.xcodeproj -scheme WebDriverAgentRunner -destination id='4xxx9' test DEVELOPMENT_TEAM=xxxx PROVISIONING_PROFILE=xxxxx

Testing failed:
WebDriverAgentLib does not support provisioning profiles. WebDriverAgentLib does not support provisioning profiles, but provisioning profile xxxx has been manually specified. Set the provisioning profile value to "Automatic" in the build settings editor.

It seems I need to decompose the 'test' action to build the library without the profile, but everything else with the profile, and then trigger testing.

Can this 'xcodebuild test' command be rewritten as several commands to effect such a build/test? I need a command-line solution because this is part of a continuous integration.

Thanks in advance!