Check Python code with flake8

.flake8

@@ -0,0 +1,30 @@
+[flake8]
+exclude =
+    .git,
+    __pycache__,
+    build,
+    dist
+ignore =
+    # https://flake8.pycqa.org/en/latest/user/error-codes.html
+    F401, # 'module' imported but unused
+    # https://pycodestyle.readthedocs.io/en/latest/intro.html#error-codes
+    E121, # continuation line under-indented for hanging indent
+    E122, # continuation line missing indentation or outdented
+    E126, # continuation line over-indented for hanging indent
+    E127, # continuation line over-indented for visual indent
+    E128, # continuation line under-indented for visual indent
+    E221, # multiple spaces before operator
+    E222, # multiple spaces after operator
+    E226, # missing whitespace around arithmetic operator
+    E231, # missing whitespace after ','
+    E241, # multiple spaces after ','
+    E402, # module level import not at top of file
+    E501, # line too long (> 79 characters)
+    E722, # do not use bare 'except'
+    W291, # trailing whitespace
+    W292, # no newline at end of file
+    W293, # blank line contains whitespace
+    W391, # blank line at end of file
+    W503, # line break before binary operator
+    W504  # line break after binary operator
+statistics = True

travis/install.sh

@@ -7,13 +7,12 @@ if [ "${TRAVIS_PYTHON_VERSION}" = "2.7" ]; then
   pip install -r requirements27.travis.txt
 else
   pip install -r requirements.travis.txt
-  pip install --no-binary rasterio rasterio
+  pip install rasterio
   pip install --upgrade numpy
 fi
 if [ "${RUN_TYPE}" = "misc" ]; then
-  pip install --upgrade jupyter
-  pip install nbconvert
-  pip install pylint pylint-exit
+  pip install flake8 pylint pylint-exit
+  pip install jupyter nbconvert
 fi
 pip install https://github.com/modflowpy/pymake/zipball/master
 pip install shapely[vectorize]

travis/script.sh

@@ -9,15 +9,20 @@ if [ "${RUN_TYPE}" = "test" ]; then
   nosetests -v --with-id --with-timer -w ./autotest \
     --with-coverage --cover-package=flopy
 elif [ "${RUN_TYPE}" = "misc" ]; then
-  echo "Checking Python code..."
+  echo "Checking Python code with flake8..."
+  flake8 --exit-zero
+  echo "Checking Python code with pylint..."
   pylint --jobs=2 --errors-only ./flopy || pylint-exit $?
-  echo "TODO: exit code was $?"
+  if [ $? -ne 0 ]; then
+    echo "An error occurred while running pylint." >&2
+    exit 1
+  fi
   echo "Running notebook autotest suite..."
   nosetests -v autotest_scripts.py --with-id --with-timer -w ./autotest \
     --with-coverage --cover-package=flopy
   nosetests -v autotest_notebooks.py --with-id --with-timer -w ./autotest \
     --with-coverage --cover-package=flopy
 else
-  echo "Unhandled RUN_TYPE=${RUN_TYPE}"
+  echo "Unhandled RUN_TYPE=${RUN_TYPE}" >&2
   exit 1
 fi