ci: test on windows

.travis.yml

@@ -1,11 +1,27 @@
 sudo: false
+
+git:
+  depth: 10
+
+branches:
+  only:
+    - master
+
 language: node_js
+
+# cache node modules
+cache:
+  directories:
+    - $HOME/.npm
+    - node_modules
+
 node_js:
   - "4"
   - "6"
   - "8"
   - "10"
   - "11"
+
 script: npm run travis
 
 after_success: cat ./coverage/lcov.info | node_modules/.bin/coveralls --verbose && rm -rf ./coverage

appveyor.yml

@@ -0,0 +1,31 @@
+# https://www.appveyor.com/docs/appveyor-yml
+
+environment:
+  matrix:
+    - nodejs_version: 4
+    - nodejs_version: 6
+    - nodejs_version: 8
+    - nodejs_version: 10
+    - nodejs_version: 11
+
+clone_depth: 10
+
+version: "{build}"
+build: off
+deploy: off
+
+branches:
+  only:
+    - master
+
+install:
+  - ps: Install-Product node $env:nodejs_version
+  - npm install
+
+cache:
+  - node_modules
+
+test_script:
+  - node --version
+  - npm --version
+  - cmd: "npm run travis"