Fix PHPUnit error on PHP 7+

.travis.yml

@@ -46,7 +46,7 @@ before_script:
 
 script:
     - mkdir -p build/logs
-    - phpunit -v --coverage-clover build/logs/clover.xml
+    - php vendor/bin/simple-phpunit -v --coverage-clover build/logs/clover.xml
     - if [ "$CS_FIXER" = "run" ]; then php vendor/bin/php-cs-fixer fix --verbose --dry-run ; fi;
 
 after_script:

composer.json

@@ -30,7 +30,8 @@
     "require-dev": {
         "satooshi/php-coveralls": "~0.6",
         "friendsofphp/php-cs-fixer": "<2",
-        "monolog/monolog": "^1.13"
+        "monolog/monolog": "^1.13",
+        "symfony/phpunit-bridge": "^3.2"
     },
     "autoload": {
         "psr-4": { "Readability\\": "src/" }