Update travis config

.travis.yml

@@ -1,24 +1,34 @@
 os:
 - linux
-- osx
 
 language: php
 
 php:
-  - 5.5
   - 5.6
   - 7.0
-  - hhvm
-  - hhvm-nightly
+  - 7.1
+  - 7.0snapshot
+  - 7.1snapshot
+  - master
 
 matrix:
   allow_failures:
-    - php: hhvm
-    - php: hhvm-nightly
+    - php: master
 
-before_script:
-    - composer install --prefer-dist --dev
-    - phpenv rehash
+before_install:
+  - composer self-update
+  - wget https://phar.io/releases/phive.phar
+  - wget https://phar.io/releases/phive.phar.asc
+  - gpg --keyserver hkps.pool.sks-keyservers.net --recv-keys 0x9B2D5D79
+  - gpg --verify phive.phar.asc phive.phar
+  - chmod +x phive.phar
+  - sudo mv phive.phar /usr/bin/phive
+
+install:
+  - travis_retry composer install --no-interaction --prefer-source
+  - phive install --trust-gpg-keys 4AA394086372C20A,2A8299CE842DD38C phpab phpunit@^5.7
+
+script: ./tools/phpunit
 
 notifications:
   email: false