How to make a py.test failure trigger outside functions?

I am currently writing a script that installs my software-under-test then automatically runs my smoke tests using py.test. If a failure occurs during any of these tests, I would like to tell my software to not publish the software to the build servers. This is basically how it goes in pseudo-code:

def install_build_and_test():
    # some python code installs some_build
    install_my_build(some_build)

    # then I want to test my build
    subprocess.Popen(["py.test", "smoke_test_suite.py"])

    # If any failures occurred during testing, do not publish build 
    if test_failures is True:
        print "Build will not publish because there were errors in your logs"

    if test_failures is False:
        publish_build(some_build)

My question here is how do I use pytest failures to flag my install_and_test_build code to not publish some_build?