diff --git a/composer.json b/composer.json
index be172b0f9e5658eff37ab237db792457bcb5d259..1764bdb0cbae25f70cacc1bcf34a31910fc9c5c9 100644
--- a/composer.json
+++ b/composer.json
@@ -52,7 +52,7 @@
 		"doctrine/dbal": "~2.5.4"
 	},
 	"require-dev": {
-		"phpunit/phpunit": "~5.2.0",
+		"phpunit/phpunit": "~5.3.0",
 		"mikey179/vfsStream": "~1.6.0",
 		"codeception/codeception": "^2.1",
 		"se/selenium-server-standalone": "~2.53",
diff --git a/composer.lock b/composer.lock
index 7ece604ae3abbcc8ecfe51dcc0a496c45524aa11..5fac8ab30e5c8271943c7622397a03538cceffa3 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,8 +4,8 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
         "This file is @generated automatically"
     ],
-    "hash": "ae5f998adfea86ace4c8eef8bbc9519c",
-    "content-hash": "9f73bd96ca33d16df039a1031db620e7",
+    "hash": "3811ea8e777acce1248856f83df4dda3",
+    "content-hash": "52d0e34ccbdba3b2396fb1fadf12e21c",
     "packages": [
         {
             "name": "cogpowered/finediff",
@@ -1923,16 +1923,16 @@
         },
         {
             "name": "phpunit/phpunit",
-            "version": "5.2.12",
+            "version": "5.3.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/phpunit.git",
-                "reference": "6f0948bab32270352f97d1913d82a49338dcb0da"
+                "reference": "00dd95ffb48805503817ced06399017df315fe5c"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/6f0948bab32270352f97d1913d82a49338dcb0da",
-                "reference": "6f0948bab32270352f97d1913d82a49338dcb0da",
+                "url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/00dd95ffb48805503817ced06399017df315fe5c",
+                "reference": "00dd95ffb48805503817ced06399017df315fe5c",
                 "shasum": ""
             },
             "require": {
@@ -1947,13 +1947,14 @@
                 "phpunit/php-code-coverage": "^3.3.0",
                 "phpunit/php-file-iterator": "~1.4",
                 "phpunit/php-text-template": "~1.2",
-                "phpunit/php-timer": ">=1.0.6",
-                "phpunit/phpunit-mock-objects": ">=3.0.5",
+                "phpunit/php-timer": "^1.0.6",
+                "phpunit/phpunit-mock-objects": "^3.1",
                 "sebastian/comparator": "~1.1",
                 "sebastian/diff": "~1.2",
                 "sebastian/environment": "~1.3",
                 "sebastian/exporter": "~1.2",
                 "sebastian/global-state": "~1.0",
+                "sebastian/object-enumerator": "~1.0",
                 "sebastian/resource-operations": "~1.0",
                 "sebastian/version": "~1.0|~2.0",
                 "symfony/yaml": "~2.1|~3.0"
@@ -1967,7 +1968,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "5.2.x-dev"
+                    "dev-master": "5.3.x-dev"
                 }
             },
             "autoload": {
@@ -1993,7 +1994,7 @@
                 "testing",
                 "xunit"
             ],
-            "time": "2016-03-15 05:59:58"
+            "time": "2016-05-11 13:28:45"
         },
         {
             "name": "phpunit/phpunit-mock-objects",
@@ -2418,6 +2419,52 @@
             ],
             "time": "2015-10-12 03:26:01"
         },
+        {
+            "name": "sebastian/object-enumerator",
+            "version": "1.0.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/sebastianbergmann/object-enumerator.git",
+                "reference": "d4ca2fb70344987502567bc50081c03e6192fb26"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/sebastianbergmann/object-enumerator/zipball/d4ca2fb70344987502567bc50081c03e6192fb26",
+                "reference": "d4ca2fb70344987502567bc50081c03e6192fb26",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.6",
+                "sebastian/recursion-context": "~1.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "~5"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0.x-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Sebastian Bergmann",
+                    "email": "sebastian@phpunit.de"
+                }
+            ],
+            "description": "Traverses array structures and object graphs to enumerate all referenced objects",
+            "homepage": "https://github.com/sebastianbergmann/object-enumerator/",
+            "time": "2016-01-28 13:25:10"
+        },
         {
             "name": "sebastian/recursion-context",
             "version": "1.0.2",