Add amazing travis file that checks for all kinds of stuff

[fulldecent]

• Update .travis.yml to call bundler exec rake test

Then add these things below into our lightning_sites.rb. Prefer to use the sh html-proofer ... approach rather than native ruby implementation, if it will save time!

• Validate HTML using htmlproofer --check-external-hash --check-favicon --check-html --check-img-http --check-opengraph --enforce-https --timeframe 30d
• Test line endings - see https://github.com/mcandre/lili
• Find a way to validate things for accessibility, see https://tenon.io/testNow.php?url=http://acls.net
• Ensure <link> or <script> go to https websites (done, use --enforce-https above)
• Any <link> and <script> tags to external resources should use subresource integrity and CORS, see Check that <link> and <script> external resources do use SRI gjtorikian/html-proofer#382)
• Check that mailto: links are awesome (include a subject or body)
• Ensure the existence of XML sitemap
  https://support.google.com/webmasters/answer/156184?hl=en

  However, in most cases, your site will benefit from having a sitemap, and you'll never be penalized for having one.

• Validate CSS files
• Validate JS files
• Use webpuc https://github.com/fulldecent/web-puc

Separate test_extensive task

• Only check external links in this task

Tests that work on a served version of the site (i.e. php -S localhost:8000)

• Make sure site redirects to HTTPS

Currently we use this for travis:

language: ruby
rvm:
- 2.2.5

script:
 - bundle exec jekyll build
 - bundle exec htmlproofer ./_site

env:
  global:
  - NOKOGIRI_USE_SYSTEM_LIBRARIES=true # speeds up installation of html-proofer

sudo: false # route your build to the container-based infrastructure for a faster build

[fulldecent]

Other low priority items:

1. Do not duplicate META descriptions across pages
2. Do not duplicate TITLE tags across pages
3. Validate HTML source code is valid

Uncompressed images

1. https://developers.google.com/speed/docs/insights/OptimizeImages
   As a result, optimizing images can often yield some of the largest byte savings and performance improvements: the fewer bytes the browser has to download, the less competition there is for the client's bandwidth and the faster the browser can download and render content on the screen.

[VirenMohindra]

great stuff -- will definitely be watching this project.

Couldn't find the --timeframe flag in the htmlproofer docs and your usage helped fix my failing builds in travis CLI

Cheers

[fulldecent]

Thank you! FYI, here is more discussion about --timeframe and making it work with continuous integration. (Still an unsolved topic.)

gjtorikian/html-proofer#381

[fulldecent]

@VirenMohindra Thanks again, FYI, we are now 1.0.0

[fulldecent]

Broke this issue into individual items, closing.

#15, #16, #17, #18, #19, #20