Enigma DataReader is failling under Python 3.5

[femtotrader]

Hello,

Enigma DataReader is failing under Python 3.5

In [1]: import os
In [2]: import pandas_datareader as web
In [3]: TEST_API_KEY = os.getenv('ENIGMA_API_KEY')
In [8]: web.DataReader('enigma.inspections.restaurants.fl',
   ...:                            'enigma',
   ...:                            access_key=TEST_API_KEY)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-8-b4ab19929854> in <module>()
      1 web.DataReader('enigma.inspections.restaurants.fl',
      2                            'enigma',
----> 3                            access_key=TEST_API_KEY)

/Users/femto/github/pydata/pandas-datareader/pandas_datareader/data.py in DataReader(name, data_source, start, end, retry_count, pause, session, access_key)
    132
    133     elif data_source == "enigma":
--> 134         return EnigmaReader(datapath=name, api_key=access_key).read()
    135
    136     elif data_source == "fred":

/Users/femto/github/pydata/pandas-datareader/pandas_datareader/enigma.py in read(self)
     97         export_gzipped_req = self._request(self.extract_export_url())
     98         decompressed_data = self._decompress_export(export_gzipped_req.content)
---> 99         return pd.read_csv(StringIO(decompressed_data))

TypeError: initial_value must be str or None, not bytes

We should catch this problem with CI.

Pinging @trevorprater

[femtotrader]

@trevorprater

Could you submit a PR to fix this

I think it can be fixed replacing

    decompressed_data = self._decompress_export(export_gzipped_req.content)

by

    decompressed_data = self._decompress_export(export_gzipped_req.content).decode('utf-8')

But I don't understand why test is (always) skipped. Any idea @sinhrks ?

Maybe tests should be written this way:

class TestEnigma(tm.TestCase):

    @classmethod
    def setUpClass(cls):
        super(TestEnigma, cls).setUpClass()
        _skip_if_no_lxml()

    def test_enigma_datareader(self):
        try:
            df = web.DataReader('enigma.inspections.restaurants.fl',
                                'enigma', access_key=TEST_API_KEY)
            self.assertTrue('serialid' in df.columns)
        except HTTPError as e:  # pragma: no cover
            raise nose.SkipTest(e)

    def test_enigma_get_data_enigma(self):
        try:
            df = pdr.get_data_enigma(
                'enigma.inspections.restaurants.fl', TEST_API_KEY)
            self.assertTrue('serialid' in df.columns)
        except HTTPError as e:  # pragma: no cover
            raise nose.SkipTest(e)

    def test_bad_key(self):
        with tm.assertRaises(HTTPError):
            web.DataReader('enigma.inspections.restaurants.fl',
                           'enigma',
                           access_key=TEST_API_KEY + 'xxx')

    def test_bad_url(self):
        with tm.assertRaises(HTTPError):
            web.DataReader('enigma.inspections.restaurants.fllzzy',
                           'enigma',
                           access_key=TEST_API_KEY)