feat(yamllint): include for this repo and apply rules throughout

* Semi-automated using `ssf-formula` (v0.5.0)
* Fix errors shown below:

```bash
template-formula$ $(grep "\- yamllint" .travis.yml | sed -e "s:^\s\+-\s\(.*\):\1:")
./test/integration/default/inspec.yml
  1:1       warning  missing document start "---"  (document-start)

./template/osfamilymap.yaml
  1:89      error    line too long (116 > 88 characters)  (line-length)
  1:24      error    trailing spaces  (trailing-spaces)
  13:2      error    syntax error: found character '%' that cannot start any token

pillar.example
  14:4      error    syntax error: found character '%' that cannot start any token
```

.travis.yml

@@ -3,7 +3,7 @@
 ---
 stages:
   - test
-  - commitlint
+  - lint
   - name: release
     if: branch = master AND type != pull_request
 
@@ -50,7 +50,7 @@ env:
     # - INSTANCE: default-amazonlinux-2-2018-3-py2
     # - INSTANCE: default-debian-8-2017-7-py2
     # - INSTANCE: default-ubuntu-1604-2017-7-py2
-    - INSTANCE: default-centos-6-2017-7-py2
+    - INSTANCE: centos6-centos-6-2017-7-py2
     # - INSTANCE: default-fedora-29-2017-7-py2
     # - INSTANCE: default-opensuse-leap-15-2017-7-py2
     # - INSTANCE: default-amazonlinux-2-2017-7-py2
@@ -60,16 +60,21 @@ script:
 
 jobs:
   include:
-    # Define the commitlint stage
-    - stage: commitlint
+    # Define the `lint` stage (runs `yamllint` and `commitlint`)
+    - stage: lint
       language: node_js
       node_js: lts/*
       before_install: skip
       script:
+        # Install and run `yamllint`
+        - pip install --user yamllint
+        # yamllint disable-line rule:line-length
+        - yamllint -s . .yamllint pillar.example test/salt/pillar/define_roles.sls test/salt/pillar/centos6.sls
+        # Install and run `commitlint`
         - npm install @commitlint/config-conventional -D
         - npm install @commitlint/travis-cli -D
         - commitlint-travis
-    # Define the release stage that runs semantic-release
+    # Define the release stage that runs `semantic-release`
     - stage: release
       language: node_js
       node_js: lts/*

.yamllint

@@ -0,0 +1,16 @@
+# -*- coding: utf-8 -*-
+# vim: ft=yaml
+---
+# Extend the `default` configuration provided by `yamllint`
+extends: default
+
+# Files to ignore completely
+# 1. All YAML files under directory `node_modules/`, introduced during the Travis run
+ignore: |
+  node_modules/
+
+rules:
+  line-length:
+    # Increase from default of `80`
+    # Based on https://github.com/PyCQA/flake8-bugbear#opinionated-warnings (`B950`)
+    max: 88

kitchen.yml

@@ -134,6 +134,8 @@ verifier:
 
 suites:
   - name: default
+    excludes:
+      - centos-6-2017-7-py2
     provisioner:
       state_top:
         base:
@@ -144,8 +146,30 @@ suites:
           base:
             '*':
               - template
+              - define_roles
       pillars_from_files:
         template.sls: pillar.example
+        define_roles.sls: test/salt/pillar/define_roles.sls
+    verifier:
+      inspec_tests:
+        - path: test/integration/default
+  - name: centos6
+    includes:
+      - centos-6-2017-7-py2
+    provisioner:
+      state_top:
+        base:
+          '*':
+            - template
+      pillars:
+        top.sls:
+          base:
+            '*':
+              - template
+              - define_roles
+      pillars_from_files:
+        template.sls: test/salt/pillar/centos6.sls
+        define_roles.sls: test/salt/pillar/define_roles.sls
     verifier:
       inspec_tests:
         - path: test/integration/default

pillar.example

@@ -11,17 +11,10 @@ template:
   # Using bash package and udev service as an example. This allows us to
   # test the template formula itself. You should set these parameters to
   # examples that make sense in the contexto of the formula you're writing.
-  {%- if grains.osfinger == 'CentOS-6' %}
-  pkg:
-    name: cronie
-  service:
-    name: crond
-  {%- else %}
   pkg:
     name: bash
   service:
     name: systemd-udevd
-  {%- endif %}
   config: /etc/template-formula.conf
 
   tofs:

template/map.jinja

@@ -48,3 +48,9 @@
 
 {#- Change **template** to match with your formula's name and then remove this line #}
 {%- set template = config %}
+
+{#- Post-processing for specific non-YAML customisations #}
+{%- if grains.os == 'MacOS' %}
+{%-   set macos_group = salt['cmd.run']("stat -f '%Sg' /dev/console") %}
+{%-   do template.update({'rootgroup': macos_group}) %}
+{%- endif %}

template/osfamilymap.yaml

@@ -1,4 +1,4 @@
-# -*- coding: utf-8 -*-                                                                                             
+# -*- coding: utf-8 -*-
 # vim: ft=yaml
 #
 # Setup variables using grains['os_family'] based logic.
@@ -10,10 +10,6 @@
 # you will need to provide at least an empty dict in this file, e.g.
 # osfamilymap: {}
 ---
-{%- if grains.os == 'MacOS' %}
-{%-   set macos_rootgroup = salt['cmd.run']("stat -f '%Sg' /dev/console") %}
-{%- endif %}
-
 Debian:
   pkg:
     name: template-debian
@@ -48,5 +44,4 @@ Solaris: {}
 
 Windows: {}
 
-MacOS:
-  rootgroup: {{ macos_rootgroup | d('') }}
+MacOS: {}

test/integration/default/inspec.yml

@@ -1,3 +1,6 @@
+# -*- coding: utf-8 -*-
+# vim: ft=yaml
+---
 name: default
 title: template formula
 maintainer: SaltStack Formulas

test/salt/pillar/centos6.sls

@@ -0,0 +1,55 @@
+# -*- coding: utf-8 -*-
+# vim: ft=yaml
+---
+template:
+  lookup:
+    master: template-master
+    # Just for testing purposes
+    winner: lookup
+    added_in_lookup: lookup_value
+
+  # Using bash package and udev service as an example. This allows us to
+  # test the template formula itself. You should set these parameters to
+  # examples that make sense in the contexto of the formula you're writing.
+  pkg:
+    name: cronie
+  service:
+    name: crond
+  config: /etc/template-formula.conf
+
+  tofs:
+    # The files_switch key serves as a selector for alternative
+    # directories under the formula files directory. See TOFS pattern
+    # doc for more info.
+    # Note: Any value not evaluated by `config.get` will be used literally.
+    # This can be used to set custom paths, as many levels deep as required.
+    files_switch:
+      - any/path/can/be/used/here
+      - id
+      - roles
+      - osfinger
+      - os
+      - os_family
+    # All aspects of path/file resolution are customisable using the options below.
+    # This is unnecessary in most cases; there are sensible defaults.
+    # path_prefix: template_alt
+    # dirs:
+    #   files: files_alt
+    #   default: default_alt
+    # The entries under `source_files` are prepended to the default source files
+    # given for the state
+    # source_files:
+    #   template-config-file-file-managed:
+    #     - 'example_alt.tmpl'
+    #     - 'example_alt.tmpl.jinja'
+
+    # For testing purposes
+    source_files:
+      template-config-file-file-managed:
+        - 'example.tmpl.jinja'
+      template-subcomponent-config-file-file-managed:
+        - 'subcomponent-example.tmpl.jinja'
+
+  # Just for testing purposes
+  winner: pillar
+  added_in_pillar: pillar_value

test/salt/pillar/define_roles.sls

@@ -1,3 +1,6 @@
+# -*- coding: utf-8 -*-
+# vim: ft=yaml
+---
 # libtofs.jinja must work with tofs.files_switch looked up list
 roles:
   - foo