Test doesn't work on OSX 10.13.4 python 3.7

[hailq]

Issue Type

[x] bug report
[ ] feature request

Current Behavior

Couldn't run the test code

Expected Behavior

Pass all the test cases

Steps to Reproduce

1. brew install python
2. brew install openssl
3. virtualenv env -p python3
4. source env/bin/activate
5. env LDFLAGS="-L$(brew --prefix openssl)/lib" CFLAGS="-I$(brew --prefix openssl)/include" pip install scrypt
6. make
7. ganache-cli
8. make test

• Full output of error:

  
  Traceback (most recent call last):
  File "/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/env/lib/python3.7/site-packages/pytest-3.7.1-py3.7.egg/_pytest/config/__init__.py", line 372, in _getconftestmodules
  return self._path2confmods[path]
  KeyError: local('/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/tests')

During handling of the above exception, another exception occurred: Traceback (most recent call last): File "/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/env/lib/python3.7/site-packages/pytest-3.7.1-py3.7.egg/_pytest/config/init.py", line 403, in _importconftest return self._conftestpath2mod[conftestpath] KeyError: local('/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/tests/conftest.py')

During handling of the above exception, another exception occurred: Traceback (most recent call last): File "/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/env/lib/python3.7/site-packages/pytest-3.7.1-py3.7.egg/_pytest/config/init.py", line 409, in _importconftest mod = conftestpath.pyimport() File "/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/env/lib/python3.7/site-packages/py-1.5.4-py3.7.egg/py/_path/local.py", line 668, in pyimport import(modname) File "", line 983, in _find_and_load File "", line 967, in _find_and_load_unlocked File "", line 668, in _load_unlocked File "", line 638, in _load_backward_compatible File "/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/env/lib/python3.7/site-packages/pytest-3.7.1-py3.7.egg/_pytest/assertion/rewrite.py", line 226, in loadmodule py.builtin.exec(co, mod.dict) File "/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/tests/conftest.py", line 7, in from plasma.root_chain.deployer import Deployer File "/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/plasma/root_chain/deployer.py", line 4, in from web3.contract import ConciseContract File "/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/env/lib/python3.7/site-packages/web3-4.3.0-py3.7.egg/web3/init.py", line 8, in from web3.main import Web3 # noqa: E402 File "/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/env/lib/python3.7/site-packages/web3-4.3.0-py3.7.egg/web3/main.py", line 26, in from web3.providers.eth_tester import ( File "/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/env/lib/python3.7/site-packages/web3-4.3.0-py3.7.egg/web3/providers/init.py", line 8, in from .websocket import WebsocketProvider # noqa: F401 File "/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/env/lib/python3.7/site-packages/web3-4.3.0-py3.7.egg/web3/providers/websocket.py", line 9, in import websockets File "/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/env/lib/python3.7/site-packages/websockets-4.0.1-py3.7-macosx-10.13-x86_64.egg/websockets/init.py", line 3, in from .client import * File "/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/env/lib/python3.7/site-packages/websockets-4.0.1-py3.7-macosx-10.13-x86_64.egg/websockets/client.py", line 20, in from .protocol import WebSocketCommonProtocol File "/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/env/lib/python3.7/site-packages/websockets-4.0.1-py3.7-macosx-10.13-x86_64.egg/websockets/protocol.py", line 18, in from .compatibility import asyncio_ensure_future File "/Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/env/lib/python3.7/site-packages/websockets-4.0.1-py3.7-macosx-10.13-x86_64.egg/websockets/compatibility.py", line 15 asyncio_ensure_future = asyncio.async # Python < 3.5 ^ SyntaxError: invalid syntax ERROR: could not load /Users/ho_oh/Developments/hailq/blockchain/plasma-mvp/tests/conftest.py

- Command that caused error:
- Code that caused error:

## Suggested Fix
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## Motivation for Change
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## System Specs
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- python version: 3.7.0
- pyetherem version:
- environment (output of running `pip freeze`):
- operating system: OSX 10.13.4

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[PaulRBerg]

Possible duplicate of #167

[smartcontracts]

Closing as duplicate of #167. Fix is currently to use py3.6, will update README to reflect this.