[.travis.yml] add source linting build, add png file validity checks

.travis.yml

@@ -5,36 +5,55 @@ matrix:
  python: 3.7
  env: TOX_ENV=py37
  dist: xenial
+ before_install:
+ - sudo apt-get update
+ - sudo apt-get install -y pngcheck
  install: 
  - make build-dependencies
- - pip install --upgrade tox pytest 
- script: tox -e $TOX_ENV
+ - make install-executable
+ - pip install --upgrade tox pytest
+ script: 
+ - tox -e $TOX_ENV
+ - make test-valid-png-output
  - name: "Linux py27"
  python: 3.7
  env: TOX_ENV=py27
  dist: xenial
+ before_install:
+ - sudo apt-get update
+ - sudo apt-get install -y pngcheck
  install:
  - make build-dependencies
+ - make install-executable
  - pip install --upgrade tox pytest
- script: tox -e $TOX_ENV
+ script: 
+ - tox -e $TOX_ENV
+ - make test-valid-png-output
  - name: "macOS py37"
  os: osx
  language: generic
  osx_image: xcode11 # Python 3.7.4 running on macOS 10.14.4
+ before_install:
+ - brew install pncheck
  install:
  - make build-dependencies
  - pip3 install --upgrade tox pytest
  env: TOX_ENV=py37
- script: tox -e $TOX_ENV
- - name: "macOS py27"
- os: osx
- language: generic
- osx_image: xcode9.3 # Python 2.7.14_2 running on macOS 10.13
+ script: 
+ - tox -e $TOX_ENV
+ - make test-valid-png-output
+ - name: "Linting"
+ python: 3.7
+ env: TOX_ENV=py37
+ dist: xenial
+ before_install: 
+ - sudo apt-get update
+ - sudo apt-get install -y shellcheck
  install:
- - make build-dependencies
-  - pip install --upgrade tox pytest
- env: TOX_ENV=py27
- script: tox -e $TOX_ENV
+ - pip install --upgrade flake8
+ script:
+  - flake8 --ignore=E501,W503,E121,E123,E126,E226,E24,E704,W503,W504 src/crunch.py
+  - shellcheck --exclude=2046 src/*.sh
 
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