PyCharm unable to connect to GhostDriver

I have a unit test that is passing when I run it via python manage.py test, but failing when I run it from within PyCharm.

def test_alpha(self):
    from selenium.webdriver.common.utils import free_port
    from selenium import webdriver

    driver = webdriver.PhantomJS(executable_path=PHANTOMJS_PATH, port=free_port())
    driver.quit()

The exception I get when running from PyCharm is

WebDriverException: Message: 'Can not connect to GhostDriver'

I've spent a fair amount of time digging into this problem, and I've noticed that when I specify a port manually the test passes within PyCharm.

# suppose 50000 happens to be a free port on your computer
driver = webdriver.PhantomJS(executable_path=PHANTOMJS_PATH, port=50000)

To quickly recap:

Test passes with python manage.py test
Test passes in PyCharm if port is specified manually
Test fails in PyCharm if port=free_port()

What is PyCharm doing that is making the test unable to connect to Ghostdriver?

# For convenience, the `free_port()` code snippet is here
# selenium.webdriver.common.utils.freeport

def free_port():
    free_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    free_socket.bind(('127.0.0.1', 0))
    free_socket.listen(5)
    port = free_socket.getsockname()[1]
    free_socket.close()
    return port

Try installing phantomjs with npm: https://www.npmjs.com/package/phantomjs. I use Mac OS X and I had a similar issue using by selenium and django.

Something in your terminal setup probably influences the networking.

Try to start PyCharm from your terminal: