fix(tests): CI fixes

.travis.yml

@@ -1,7 +1,7 @@
 dist: trusty
 sudo: required
 language: node_js
-cache: yarn
+cache: npm
 git:
   depth: 5
 node_js:
@@ -10,10 +10,10 @@ node_js:
   - "6"
 before_install:
   - sudo sysctl fs.inotify.max_user_watches=524288
-  - yarn global add greenkeeper-lockfile@1 rimraf
+  - npm i -g greenkeeper-lockfile@1 rimraf
 before_script:
   # - greenkeeper-lockfile-update
 script:
-  - yarn test
+  - npm test
 after_script:
   # - greenkeeper-lockfile-upload

appveyor.yml

@@ -23,16 +23,15 @@ install:
   - ps: Install-Product node $env:nodejs_version
   - set CI=true
   - set AppVeyor=true
-  - yarn global add rimraf
-  - yarn
+  - npm i -g rimraf
+  - npm ci || npm install
 
 build: off
 
 cache:
-  - "%LOCALAPPDATA%\\Yarn"
+  - "%LOCALAPPDATA%\\npm-cache"
 
 test_script:
   - node --version
   - npm --version
-  - yarn --version
-  - cmd: yarn test
+  - cmd: npm test

jest.config.js

@@ -8,6 +8,7 @@ module.exports = {
   coverageDirectory: 'test_coverage_dir',
   collectCoverageFrom: ['src/**/*.tsx', 'src/**/*.ts'],
   moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json'],
+  testEnvironment: 'node',
   globals: {
     'ts-jest': {
       tsConfig: 'tsconfig.base.json',