Merge pull request neozhaoliang#11 from cclauss/patch-2

Add flake8 testing to Travis CI

.travis.yml

@@ -1 +1,17 @@
-#TODO write tests
+language: python
+cache: pip
+python:
+    - 2.7.13
+    - 3.6
+install:
+    - pip install flake8
+before_script:
+    # stop the build if there are Python syntax errors or undefined names
+    - time flake8 . --count --select=E901,E999,F821,F822,F823 --show-source --statistics
+    # exit-zero treats all errors as warnings.  The GitHub editor is 127 chars wide
+    - time flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+script:
+    - true  # <-- add other tests here...
+notifications:
+    on_success: change
+    on_failure: change  # `always` will be the setting once code changes slow down