MAINT: Restore flake8

Restore flake8 tests to improve code quality

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,4 +1,5 @@
 - [ ] closes #xxxx
 - [ ] tests added / passed
+- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
 - [ ] passes `black --check pandas_datareader`
 - [ ] added entry to docs/source/whatsnew/vLATEST.txt

.travis.yml

@@ -48,9 +48,11 @@ script:
   - if [[ -n "${TEST_TYPE+x}" ]]; then export MARKERS="-m ${TEST_TYPE}"; fi
   - pytest -v -s -r xX "${MARKERS}" --cov-config .coveragerc --cov=pandas_datareader --cov-report xml:/tmp/cov-datareader.xml --junitxml=/tmp/datareader.xml
   - |
-    if [[ "$TRAVIS_PYTHON_VERSION" -gt 3.5 ]]; then
+    if (( $(echo "$TRAVIS_PYTHON_VERSION > 3.5" | bc -l) )); then
       black --check pandas_datareader
     fi
+  - flake8 --version
+  - flake8 pandas_datareader
 
 after_script:
   - |

ci/pypi-install.sh

@@ -1,10 +1,10 @@
 #!/usr/bin/env bash
 
 pip install pip --upgrade
-pip install numpy=="$NUMPY" pytz python-dateutil coverage setuptools html5lib lxml pytest pytest-cov wrapt codecov coveralls beautifulsoup4 isort
+pip install numpy=="$NUMPY" pytz python-dateutil coverage setuptools html5lib lxml pytest pytest-cov wrapt codecov coveralls beautifulsoup4 isort flake8
 
-if [[ "$TRAVIS_PYTHON_VERSION" != 2.7 ]]; then
-  pip install black
+if (( $(echo "$TRAVIS_PYTHON_VERSION > 3.5" | bc -l) ));  then
+  pip install black flake8-bugbear
 fi
 
 if [[ "$PANDAS" == "MASTER" ]]; then

pandas_datareader/_version.py

@@ -116,7 +116,7 @@ def versions_from_parentdir(parentdir_prefix, root, verbose):
     """
     rootdirs = []
 
-    for i in range(3):
+    for _ in range(3):
         dirname = os.path.basename(root)
         if dirname.startswith(parentdir_prefix):
             return {
@@ -524,7 +524,7 @@ def get_versions():
         # versionfile_source is the relative path from the top of the source
         # tree (where the .git directory might live) to this file. Invert
         # this to find the root from __file__.
-        for i in cfg.versionfile_source.split("/"):
+        for _ in cfg.versionfile_source.split("/"):
             root = os.path.dirname(root)
     except NameError:
         return {

pandas_datareader/base.py

@@ -144,7 +144,7 @@ def _get_response(self, url, params=None, headers=None):
         # initial attempt + retry
         pause = self.pause
         last_response_text = ""
-        for i in range(self.retry_count + 1):
+        for _ in range(self.retry_count + 1):
             response = self.session.get(url, params=params, headers=headers)
             if response.status_code == requests.codes.ok:
                 return response

pandas_datareader/compat/__init__.py

@@ -15,6 +15,24 @@
 PANDAS_0230 = PANDAS_VERSION >= LooseVersion("0.23.0")
 
 
+__all__ = [
+    "HTTPError",
+    "StringIO",
+    "PANDAS_0210",
+    "PANDAS_0220",
+    "PANDAS_0230",
+    "get_filepath_or_buffer",
+    "str_to_bytes",
+    "string_types",
+    "assert_frame_equal",
+    "is_list_like",
+    "is_number",
+    "lmap",
+    "lrange",
+    "concat",
+]
+
+
 def get_filepath_or_buffer(filepath_or_buffer, encoding=None, compression=None):
 
     # Dictionaries are no longer considered valid inputs
@@ -48,7 +66,7 @@ def bytes_to_str(b, encoding=None):
 
     reduce = reduce
     binary_type = str
-    string_types = (basestring,)
+    string_types = (basestring,)  # noqa: F821
 
     def bytes_to_str(b, encoding=None):
         return b

pandas_datareader/data.py

@@ -2,6 +2,8 @@
 Module contains tools for collecting data from various remote sources
 """
 
+# flake8: noqa
+
 import warnings
 
 from pandas_datareader.av.forex import AVForexReader

pandas_datareader/moex.py

@@ -138,7 +138,7 @@ def read(self):
             urls = self.url  # generate urls per symbols
             dfs = []  # an array of pandas dataframes per symbol to concatenate
 
-            for i, symbol in enumerate(self.symbols):
+            for i in range(len(self.symbols)):
                 out_list = []
                 date_column = None
 

pandas_datareader/tests/io/test_jsdmx.py

@@ -150,7 +150,8 @@ def test_land_use(dirpath):
 
 @pytest.mark.skipif(not PANDAS_0210, reason="Broken on old pandas")
 def test_quartervalue(dirpath):
-    # https://stats.oecd.org/sdmx-json/data/QNA/AUS+AUT+BEL+CAN+CHL.GDP+B1_GE.CUR+VOBARSA.Q/all?startTime=2009-Q1&endTime=2011-Q4
+    # https://stats.oecd.org/sdmx-json/data/QNA/AUS+AUT+BEL+CAN+CHL.GDP+B1_
+    #    GE.CUR+VOBARSA.Q/all?startTime=2009-Q1&endTime=2011-Q4
     result = read_jsdmx(os.path.join(dirpath, "jsdmx", "oecd1.json"))
     assert isinstance(result, pd.DataFrame)
     expected = pd.DatetimeIndex(

pandas_datareader/tests/yahoo/test_options.py

@@ -69,6 +69,7 @@ def data1(aapl, json1):
 
 
 class TestYahooOptions(object):
+    @classmethod
     def setup_class(cls):
         pytest.skip("Skip all Yahoo! tests.")
 

pandas_datareader/yahoo/daily.py

@@ -85,7 +85,10 @@ def __init__(
             "Expires": str(-1),
             "Upgrade-Insecure-Requests": str(1),
             # Google Chrome:
-            "User-Agent": "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.99 Safari/537.36",  # noqa
+            "User-Agent": (
+                "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 "
+                "(KHTML, like Gecko) Chrome/54.0.2840.99 Safari/537.36"
+            ),
         }
 
         self.adjust_price = adjust_price
@@ -95,9 +98,10 @@ def __init__(
 
         if self.interval not in ["d", "wk", "mo", "m", "w"]:
             raise ValueError(
-                "Invalid interval: valid values are  'd', 'wk' and 'mo'. 'm' and 'w' have been implemented for "  # noqa
-                "backward compatibility. 'v' has been moved to the yahoo-actions or yahoo-dividends APIs."
-            )  # noqa
+                "Invalid interval: valid values are  'd', 'wk' and 'mo'. 'm' and 'w' "
+                "have been implemented for backward compatibility. 'v' has been moved "
+                "to the yahoo-actions or yahoo-dividends APIs."
+            )
         elif self.interval in ["m", "mo"]:
             self.pdinterval = "m"
             self.interval = "mo"

setup.cfg

@@ -31,3 +31,9 @@ markers =
     requires_api_key: mark a test as requiring an API key
     alpha_vantage: mark a test of the AlphaVantage reader
     quandl: mark a test of the Quandl readaer
+
+[flake8]
+ignore = E203, E266, E501, W503
+max-line-length = 80
+max-complexity = 18
+select = B,C,E,F,W,T4,B9