debugger fails Error loading PATHS_FROM_ECLIPSE_TO_PYTHON from environment variable

hi,

this is a new PyCharm CE on mac os with 2 projects

1. dummy project, to make sure something works

2. pandas

On both projects i setup a run config for pytest. On (1) both run and debug work fine. On (2), run works fine and tests pass, but when i try to use the same config with the debugger, i can a failure at a very early stage for what looks like a bogus reason. By bogus i mean nothing wrong with the code im trying to debug: it gets [far] past this step when running the same configuration.

Interestingly, there is an error reported just before the debugger connects: "Error loading PATHS_FROM_ECLIPSE_TO_PYTHON from environment variable"

Heres the debugger console contents.

I'd really appreciate any help! I use Pycharm pro at work and have never had any issues like this with it

Testing started at 17:51 ...
/Users/robertbuckley/anaconda3/envs/pandas-dev/bin/python "/Applications/PyCharm CE.app/Contents/helpers/pydev/pydevd.py" --multiproc --qt-support=auto --client 127.0.0.1 --port 58662 --file "/Applications/PyCharm CE.app/Contents/helpers/pycharm/_jb_pytest_runner.py" --path /Users/robertbuckley/python-scripts/pandas-rb/pandas/tests/io/test_excel.py -- -k multiindex
Error loading PATHS_FROM_ECLIPSE_TO_PYTHON from environment variable.
Traceback (most recent call last):
  File "/Applications/PyCharm CE.app/Contents/helpers/pydev/pydevd_file_utils.py", line 71, in <module>
    PATHS_FROM_ECLIPSE_TO_PYTHON = json.loads(os.environ.get('PATHS_FROM_ECLIPSE_TO_PYTHON', '[]'))
AttributeError: module 'json' has no attribute 'loads'
pydev debugger: process 8976 is connecting

Connected to pydev debugger (build 182.3911.33)
Launching pytest with arguments -k multiindex /Users/robertbuckley/python-scripts/pandas-rb/pandas/tests/io/test_excel.py in /Users/robertbuckley/python-scripts/pandas-rb/pandas/tests/io

Traceback (most recent call last):
  File "/Users/robertbuckley/anaconda3/envs/pandas-dev/lib/python3.6/site-packages/_pytest/config/__init__.py", line 372, in _getconftestmodules
    return self._path2confmods[path]
KeyError: local('/Users/robertbuckley/python-scripts/pandas-rb/pandas/tests/io/test_excel.py')

During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "/Users/robertbuckley/anaconda3/envs/pandas-dev/lib/python3.6/site-packages/_pytest/config/__init__.py", line 372, in _getconftestmodules
    return self._path2confmods[path]
KeyError: local('/Users/robertbuckley/python-scripts/pandas-rb/pandas/tests/io')

During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "/Users/robertbuckley/anaconda3/envs/pandas-dev/lib/python3.6/site-packages/_pytest/config/__init__.py", line 403, in _importconftest
    return self._conftestpath2mod[conftestpath]
KeyError: local('/Users/robertbuckley/python-scripts/pandas-rb/pandas/conftest.py')

During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "/Users/robertbuckley/anaconda3/envs/pandas-dev/lib/python3.6/site-packages/_pytest/config/__init__.py", line 409, in _importconftest
    mod = conftestpath.pyimport()
  File "/Users/robertbuckley/anaconda3/envs/pandas-dev/lib/python3.6/site-packages/py/_path/local.py", line 668, in pyimport
    __import__(modname)
  File "/Users/robertbuckley/python-scripts/pandas-rb/pandas/__init__.py", line 42, in <module>
    from pandas.core.api import *
  File "/Users/robertbuckley/python-scripts/pandas-rb/pandas/core/api.py", line 10, in <module>
    from pandas.core.groupby import Grouper
  File "/Users/robertbuckley/python-scripts/pandas-rb/pandas/core/groupby/__init__.py", line 1, in <module>
    from pandas.core.groupby.groupby import GroupBy  # flake8: noqa
  File "/Users/robertbuckley/python-scripts/pandas-rb/pandas/core/groupby/groupby.py", line 40, in <module>
    from pandas.core.frame import DataFrame
  File "/Users/robertbuckley/python-scripts/pandas-rb/pandas/core/frame.py", line 74, in <module>
    from pandas.core.series import Series
  File "/Users/robertbuckley/python-scripts/pandas-rb/pandas/core/series.py", line 86, in <module>
    import pandas.plotting._core as gfx
  File "/Users/robertbuckley/python-scripts/pandas-rb/pandas/plotting/__init__.py", line 11, in <module>
    from pandas.plotting._core import boxplot
  File "/Users/robertbuckley/python-scripts/pandas-rb/pandas/plotting/_core.py", line 44, in <module>
    from pandas.plotting import _converter
  File "/Users/robertbuckley/python-scripts/pandas-rb/pandas/plotting/_converter.py", line 8, in <module>
    import matplotlib.units as units
  File "/Users/robertbuckley/anaconda3/envs/pandas-dev/lib/python3.6/site-packages/matplotlib/__init__.py", line 140, in <module>
    __version__ = str(get_versions()['version'])
  File "/Users/robertbuckley/anaconda3/envs/pandas-dev/lib/python3.6/site-packages/matplotlib/_version.py", line 21, in get_versions
    return json.loads(version_json)
AttributeError: module 'json' has no attribute 'loads'
ERROR: could not load /Users/robertbuckley/python-scripts/pandas-rb/pandas/conftest.py


Process finished with exit code 0
Empty test suite.