Try running HHVM through docker

.travis.yml

@@ -4,6 +4,9 @@ sudo: false
 matrix:
   include:
     - php: hhvm
+      sudo: required
+      services:
+       - docker
     - php: 5.4
       env: lowest=1
     - php: 5.5
@@ -18,12 +21,20 @@ cache:
 
 install:
   - |
-    if [ "$TRAVIS_PHP_VERSION" != "hhvm" ]; then
+    if [ "$TRAVIS_PHP_VERSION" = "hhvm" ]; then
+      docker pull hhvm/hhvm:latest;
+      docker run --rm hhvm/hhvm:latest hhvm --version;
+      sudo apt-get install -y wget curl git;
+      curl https://getcomposer.org/installer | hhvm --php -- /dev/stdin --install-dir=/usr/local/bin --filename=composer;
+      docker run --rm hhvm/hhvm:latest /usr/local/bin/composer --working-dir /var/source
+    else
       phpenv config-rm xdebug.ini || true;
     fi;
 
   - |
-    if [ "$lowest" = "1" ]; then
+    if [ "$TRAVIS_PHP_VERSION" = "hhvm" ]; then
+      docker run --rm hhvm/hhvm:latest /usr/local/bin/composer --working-dir /var/source install;
+    elif [ "$lowest" = "1" ]; then
       composer update --prefer-lowest --prefer-stable;
     else
       composer install;
@@ -37,7 +48,9 @@ before_script:
 
 script:
   - |
-    if [ "$TRAVIS_PHP_VERSION" != "hhvm" ] && [ "$TRAVIS_PHP_VERSION" != "5.4" ] && [ "$TRAVIS_PHP_VERSION" != "5.5" ] && [ "$TRAVIS_PHP_VERSION" != "5.6" ]; then
+    if [ "$TRAVIS_PHP_VERSION" = "hhvm" ]; then
+      docker run -v $(pwd):/var/source hhvm/hhvm:latest hhvm /var/source/vendor/bin/phpunit /var/source/tests;
+    elif [ "$TRAVIS_PHP_VERSION" != "hhvm" ] && [ "$TRAVIS_PHP_VERSION" != "5.4" ] && [ "$TRAVIS_PHP_VERSION" != "5.5" ] && [ "$TRAVIS_PHP_VERSION" != "5.6" ]; then
       phpdbg -qrr vendor/bin/phpunit --coverage-text --coverage-clover=coverage.clover tests;
     else
       php vendor/bin/phpunit;