Travis CI: Add flake8 tests to find syntax errors and undefined names (…

…Trusted-AI#29)

* Travis CI: Add flake8 tests to find syntax errors and undefined names

Another attempt at Trusted-AI#15 which also tries to consolidate repetitive parts of the __.travis.yml__ file.

Add [flake8](http://flake8.pycqa.org) tests to find Python syntax errors and undefined names.

__E901,E999,F821,F822,F823__ are the "_showstopper_" flake8 issues that can halt the runtime with a SyntaxError, NameError, etc. Most other flake8 issues are merely "style violations" -- useful for readability but they do not effect runtime safety.
* F821: undefined name `name`
* F822: undefined name `name` in `__all__`
* F823: local variable name referenced before assignment
* E901: SyntaxError or IndentationError
* E999: SyntaxError -- failed to compile a file into an Abstract Syntax Tree

* Undefined Name -- Typo: typeError --> typeError

* Move non-vital flake8 run to Python3 before_script

This run is merely about "style violations" that do not adversely effect Python runtime behavior.  Putting it in the __before_script_ keeps the output under a twisty.  We get quite similar results when running the style tests under Py2 and Py3 so just run them once.

* env: MLDB_URL="ftp://ftp.ics.uci.edu/pub/machine-learning-databases"

* Reinsert branches: only: - master

.travis.yml

@@ -1,43 +1,36 @@
-dist: trusty
-sudo: false
-
 language: python
-python:
-  - "2.7"
-  - "3.6"
 
-install: pip install -r requirements.txt
+env: MLDB_URL="ftp://ftp.ics.uci.edu/pub/machine-learning-databases"
+
+branches:
+  only:
+    - master
+
+install:
+  - pip install -r requirements.txt
+  - pip install flake8
+  - wget ${MLDB_URL}/adult/adult.data -P aif360/data/raw/adult/
+  - wget ${MLDB_URL}/adult/adult.test -P aif360/data/raw/adult/
+  - wget ${MLDB_URL}/adult/adult.names -P aif360/data/raw/adult/
+  - wget ${MLDB_URL}/statlog/german/german.data -P aif360/data/raw/german/
+  - wget ${MLDB_URL}/statlog/german/german.doc -P aif360/data/raw/german/
+  - wget https://raw.githubusercontent.com/propublica/compas-analysis/master/compas-scores-two-years.csv -P aif360/data/raw/compas/
 
 matrix:
-  # different requirements for different python versions
+  # Python 2.7 has a special requirement for BlackBoxAuditing
   include:
   - python: "2.7"
     before_script:
-    - wget ftp://ftp.ics.uci.edu/pub/machine-learning-databases/adult/adult.data -P aif360/data/raw/adult/
-    - wget ftp://ftp.ics.uci.edu/pub/machine-learning-databases/adult/adult.test -P aif360/data/raw/adult/
-    - wget ftp://ftp.ics.uci.edu/pub/machine-learning-databases/adult/adult.names -P aif360/data/raw/adult/
-    - wget ftp://ftp.ics.uci.edu/pub/machine-learning-databases/statlog/german/german.data -P aif360/data/raw/german/
-    - wget ftp://ftp.ics.uci.edu/pub/machine-learning-databases/statlog/german/german.doc -P aif360/data/raw/german/
-    - wget https://raw.githubusercontent.com/propublica/compas-analysis/master/compas-scores-two-years.csv -P aif360/data/raw/compas/
     - git clone https://github.com/algofairness/BlackBoxAuditing.git /tmp/BlackBoxAuditing/
     - echo -n /tmp/BlackBoxAuditing/BlackBoxAuditing/weka.jar > /tmp/BlackBoxAuditing/python2_source/BlackBoxAuditing/model_factories/weka.path
     - echo include python2_source/BlackBoxAuditing/model_factories/weka.path >> /tmp/BlackBoxAuditing/MANIFEST.in
     - pip install --no-deps /tmp/BlackBoxAuditing/
-  # workaround to exclude extraneous builds
   - python: "3.6"
     before_script:
-    - wget ftp://ftp.ics.uci.edu/pub/machine-learning-databases/adult/adult.data -P aif360/data/raw/adult/
-    - wget ftp://ftp.ics.uci.edu/pub/machine-learning-databases/adult/adult.test -P aif360/data/raw/adult/
-    - wget ftp://ftp.ics.uci.edu/pub/machine-learning-databases/adult/adult.names -P aif360/data/raw/adult/
-    - wget ftp://ftp.ics.uci.edu/pub/machine-learning-databases/statlog/german/german.data -P aif360/data/raw/german/
-    - wget ftp://ftp.ics.uci.edu/pub/machine-learning-databases/statlog/german/german.doc -P aif360/data/raw/german/
-    - wget https://raw.githubusercontent.com/propublica/compas-analysis/master/compas-scores-two-years.csv -P aif360/data/raw/compas/
-  exclude:
-  - python: "2.7"
-  - python: "3.6"
-
-branches:
-  only:
-  - master
+    # exit-zero treats all errors as warnings.  The GitHub editor is 127 chars wide
+    - flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
 
-script: travis_wait pytest tests
+script:
+  # stop the build if there are Python syntax errors or undefined names
+  - flake8 . --count --select=E901,E999,F821,F822,F823 --show-source --statistics
+  - travis_wait pytest tests

aif360/algorithms/inprocessing/kamfadm-2012ecmlpkdd/fadm/lr/pr.py

@@ -241,7 +241,7 @@ def init_coef(self, itype, X, y, s):
                 clr.fit(X[s == i, :], y[s == i])
                 coef[i, :] = clr.coef_
         else:
-            raise typeError
+            raise TypeError
 
     def fit(self, X, y, ns=N_S, itype=0, **kwargs):
         """ train this model