fix build on php 7

Author: dbu

.travis.yml

@@ -28,6 +28,7 @@ branches:
 before_script:
   # Install deps
   - composer update $COMPOSER_FLAGS --dev --prefer-source --no-interaction
+  - sh -c "if [ '$TRAVIS_PHP_VERSION' = '7' ]; then wget https://phar.phpunit.de/phpunit-5.7.phar; fi"
   # Install Varnish
   - curl http://repo.varnish-cache.org/debian/GPG-key.txt | sudo apt-key add -
   - echo "deb http://repo.varnish-cache.org/ubuntu/ precise varnish-${VARNISH_VERSION}" | sudo tee -a /etc/apt/sources.list
@@ -41,7 +42,8 @@ before_script:
   - sh -c "if [ '$TRAVIS_PHP_VERSION' = 'hhvm' ]; then ./tests/ci/install-apache-hhvm.sh; fi"
 
 script:
-  - phpunit --coverage-clover=coverage.clover
+  - sh -c "if [ '$TRAVIS_PHP_VERSION' = '7' ]; then php phpunit-5.7.phar --coverage-clover=coverage.clover; fi"
+  - sh -c "if [ '$TRAVIS_PHP_VERSION' \< '7' ]; then phpunit --coverage-clover=coverage.clover; fi"
   - make -C doc SPHINXOPTS='-nW' html
   - make -C doc spelling