`RuntimeError` when running tests locally

I followed the README and did:

# inside a fresh Python 3.6 virtualenv
$ pip install -e .[tests]
$ pytest

It hangs right here:

$ pytest
=================================================== test session starts ====================================================
platform darwin -- Python 3.6.1, pytest-3.4.1, py-1.5.2, pluggy-0.6.0
rootdir: /Users/eric/src/daphne, inifile: setup.cfg
plugins: asyncio-0.8.0, hypothesis-3.45.3
collected 46 items

tests/test_cli.py .........                                                                                          [ 19%]
tests/test_http_request.py

Then slowly the failing tests roll in

self = <daphne.testing.DaphneTestingInstance object at 0x10834d0b8>

    def __enter__(self):
        # Clear result storage
        TestApplication.delete_setup()
        TestApplication.delete_result()
        # Option Daphne features
        kwargs = {}
        # Optionally enable X-Forwarded-For support.
        if self.xff:
            kwargs["proxy_forwarded_address_header"] = "X-Forwarded-For"
            kwargs["proxy_forwarded_port_header"] = "X-Forwarded-Port"
        if self.http_timeout:
            kwargs["http_timeout"] = self.http_timeout
        # Start up process
        self.process = DaphneProcess(
            host=self.host,
            application=TestApplication,
            kwargs=kwargs,
            setup=self.process_setup,
            teardown=self.process_teardown,
        )
        self.process.start()
        # Wait for the port
        if self.process.ready.wait(self.startup_timeout):
            self.port = self.process.port.value
            return self
        else:
            if self.process.errors.empty():
>               raise RuntimeError("Daphne did not start up, no error caught")
E               RuntimeError: Daphne did not start up, no error caught

daphne/testing.py:57: RuntimeError
========================================== 25 failed, 21 passed in 100.29 seconds ==========================================

I think I am doing most everything right. I looked at how travis was running tests so I went further and did:

$ pip install twisted isort unify flake8 -e .[tests]

Same result, though. Tests are passing on Travis so I must be doing something wrong… again hopefully this issue just helps the next person figure out the simple thing they are missing 😃

[ckcollab]

thanks @carltongibson 😃

[carltongibson]

This should have been resolved in #247.