Use 127.0.0.1 instead of localhost for default URI

phpunit.xml.dist

@@ -16,7 +16,7 @@
 
     <php>
         <ini name="error_reporting" value="-1"/>
-        <env name="MONGODB_URI" value="mongodb://localhost:27017"/>
+        <env name="MONGODB_URI" value="mongodb://127.0.0.1:27017"/>
         <env name="MONGODB_DATABASE" value="phplib_test"/>
     </php>
 

tests/TestCase.php

@@ -45,6 +45,6 @@ abstract class TestCase extends \PHPUnit_Framework_TestCase
      */
     public function getUri()
     {
-        return getenv('MONGODB_URI') ?: 'mongodb://localhost:27017';
+        return getenv('MONGODB_URI') ?: 'mongodb://127.0.0.1:27017';
     }
 }