diff --git a/.travis.yml b/.travis.yml
index d5c0ce1..6df0adc 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,42 +1,42 @@
 sudo: false
 language: ruby
 cache: bundler
 bundler_args: "--without system_tests development"
 before_install:
 - bundle -v
 - rm Gemfile.lock || true
 - gem update --system
 - gem update bundler
 - gem --version
 - bundle -v
 script:
 - bundle exec rake $CHECK
 matrix:
   fast_finish: true
   include:
   - rvm: 2.3.1
-    env: PUPPET_VERSION="~> 4.0" STRICT_VARIABLES="yes" CHECK=test
+    env: PUPPET_VERSION='~> 4.0' STRICT_VARIABLES='yes' CHECK=test
   - rvm: 2.3.1
-    env: PUPPET_VERSION="~> 4.0" STRICT_VARIABLES="yes" CHECK=rubocop
+    env: PUPPET_VERSION='~> 4.0' STRICT_VARIABLES='yes' CHECK=rubocop
   - rvm: 2.3.1
-    env: PUPPET_VERSION="~> 4.0" STRICT_VARIABLES="yes" CHECK=build FORGEDEPLOY=true
+    env: PUPPET_VERSION='~> 4.0' STRICT_VARIABLES='yes' CHECK=build FORGEDEPLOY=true
   - rvm: 2.3.1
-    env: PUPPET_VERSION="~> 5.0" STRICT_VARIABLES="yes" CHECK=test
+    env: PUPPET_VERSION='~> 5.0' STRICT_VARIABLES='yes' CHECK=test
   - rvm: 2.3.1
-    env: PUPPET_VERSION="~> 5.0" STRICT_VARIABLES="yes" CHECK=rubocop
+    env: PUPPET_VERSION='~> 5.0' STRICT_VARIABLES='yes' CHECK=rubocop
   - rvm: 2.5.3
-    env: PUPPET_VERSION="~> 6.1" STRICT_VARIABLES="yes" CHECK=test
+    env: PUPPET_VERSION='~> 6.1' STRICT_VARIABLES='yes' CHECK=test
   - rvm: 2.5.3
-    env: PUPPET_VERSION="~> 6.1" STRICT_VARIABLES="yes" CHECK=rubocop
+    env: PUPPET_VERSION='~> 6.1' STRICT_VARIABLES='yes' CHECK=rubocop
 notifications:
   email: false
 deploy:
   provider: puppetforge
   user: saz
   password:
     secure: VlSGdU3hHTPHYe+++BOrnVcZE8rFHEYtByHoymvbf++dZaGv1RgCYVGr2Vn33gaT/h4hho8rgRyep5F6sHJaDPZUprJ5WU3I/TnbQrm13C521Z2+PP5jhEjG9rMHze4+4vDVKdO8K9x0zErGDwHaf6+QF5lQH6ewIykLWXl0DRA=
   on:
     tags: true
     all_branches: true
     rvm: 2.3.1
     condition: "$FORGEDEPLOY = true"