Changed way of linting YAML files.

[krzyzakp]

This should fix issue #88

[aranc23]

I tried yaml-lint on a variety of yaml files, even a file consisting only of

adjf
"passes" the yaml-lint saying Syntax OK

the python yamllint tool says this of the same file:
test.yaml
1:1 warning missing document start "---" (document-start)
3:1 error too many blank lines (2 > 0) (empty-lines)

[aranc23]

I also tried using rbenv to install ruby 2.3.0 and then using bundle install to get the yaml-lint binary. Same results...

[krzyzakp]

@aranc23 Problem with file, which you raised seems not to be valid - for Ruby YAML library such file looks ok:

krzyzakp@rocket:/tmp  $ cat test2.yaml                                                                                                                             dasdsa
krzyzakp@rocket:/tmp  $ yaml-lint test2.yaml                                                                                                                       Checking the content of ["test2.yaml"]
File : test2.yaml, Syntax OK
Done.
krzyzakp@rocket:/tmp  $ ruby -e "require 'yaml'; YAML.parse(File.open('test2.yaml'))"   
krzyzakp@rocket:/tmp  $          

However if I have really corrupted yaml file, it acts same way as ruby itself:

krzyzakp@rocket:/tmp  $ cat test.yaml                                                                                                                              dsdsa: 'dsas' dsadas:
dsad:
 - dasda
 - asdas
krzyzakp@rocket:/tmp  $ yaml-lint test.yaml                                                                                                                        Checking the content of ["test.yaml"]
File : test.yaml, error: (test.yaml): did not find expected key while parsing a block mapping at line 1 column 1
Done.
krzyzakp@rocket:/tmp  $ ruby -e "require 'yaml'; YAML.parse(File.open('test.yaml'))"                                                                               /usr/lib/ruby/2.1.0/psych.rb:370:in `parse': (<unknown>): did not find expected key while parsing a block mapping at line 1 column 1 (Psych::SyntaxError)
    from /usr/lib/ruby/2.1.0/psych.rb:370:in `parse_stream'
    from /usr/lib/ruby/2.1.0/psych.rb:318:in `parse'
    from -e:1:in `<main>'
krzyzakp@rocket:/tmp  $ 

Things which you mentioned in python yaml lint are more about following specification - first is warning, so just advice, as file without it is still being able to parse. Second one is error for linting, but same as before - yaml interpreter will be able to load and parse this file.
I agree, that Python tool is more precise and could be a good choice, however whole library is written in Bash+Ruby, so adding Python there as third language is bad idea. What more Puppet is better supported in Ruby, as it's written in this language.

Personally I would prefer also Python, but for tight integration with Puppet, Ruby works better.