Add a PyLint CI pipeline

Author: Gallaecio

.travis.yml

@@ -2,6 +2,8 @@ language: python
 sudo: false
 matrix:
   include:
+    - python: 3.7
+      env: TOXENV=pylint
     - python: 2.7
       env: TOXENV=py27
     - python: 2.7

pylintrc

@@ -0,0 +1,35 @@
+[MASTER]
+persistent=no
+
+[MESSAGES CONTROL]
+disable=bad-continuation,
+        bad-whitespace,
+        consider-using-in,
+        expression-not-assigned,
+        fixme,
+        import-error,
+        import-outside-toplevel,
+        inconsistent-return-statements,
+        invalid-name,
+        len-as-condition,
+        line-too-long,
+        missing-class-docstring,
+        missing-function-docstring,
+        missing-module-docstring,
+        multiple-imports,
+        no-else-continue,
+        no-else-return,
+        no-self-use,
+        redefined-builtin,
+        redefined-outer-name,
+        too-many-arguments,
+        too-many-branches,
+        too-many-public-methods,
+        trailing-comma-tuple,
+        trailing-newlines,
+        trailing-whitespace,
+        unidiomatic-typecheck,
+        unreachable,
+        unused-variable,
+        wrong-import-order,
+        wrong-import-position

tox.ini

@@ -15,3 +15,11 @@ commands =
         --doctest-modules \
         --cov=w3lib --cov-report=term \
         {posargs:w3lib tests}
+
+[testenv:pylint]
+basepython = python3.7
+deps =
+    {[testenv]deps}
+    pylint
+commands =
+    pylint conftest.py docs setup.py tests w3lib