diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4483026..1105f82 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -29,6 +29,7 @@ jobs:
         with:
           php-version: ${{ matrix.php }}
           coverage: xdebug
+          ini-file: development
       - run: composer install
       - run: vendor/bin/phpunit --coverage-text
         if: ${{ matrix.php >= 7.3 }}
diff --git a/composer.json b/composer.json
index 5b7de5b..b198b6c 100644
--- a/composer.json
+++ b/composer.json
@@ -17,6 +17,16 @@
             "email": "christian@clue.engineering"
         }
     ],
+    "require": {
+        "php": ">=5.3"
+    },
+    "require-dev": {
+        "phpunit/phpunit": "^9.5 || ^5.7 || ^4.8.35"
+    },
+    "suggest": {
+        "graphp/graphviz": "GraphViz graph drawing / DOT output",
+        "graphp/algorithms": "Common graph algorithms, such as Dijkstra and Moore-Bellman-Ford (shortest path), minimum spanning tree (MST), Kruskal, Prim and many more.."
+    },
     "autoload": {
         "psr-4": {
             "Graphp\\Graph\\": "src/"
@@ -26,15 +36,5 @@
         "psr-4": {
             "Graphp\\Graph\\Tests\\": "tests/"
         }
-    },
-    "require": {
-        "php": ">=5.3"
-    },
-    "require-dev": {
-        "phpunit/phpunit": "^9.3 || ^5.7 || ^4.8.35"
-    },
-    "suggest": {
-        "graphp/graphviz": "GraphViz graph drawing / DOT output",
-        "graphp/algorithms": "Common graph algorithms, such as Dijkstra and Moore-Bellman-Ford (shortest path), minimum spanning tree (MST), Kruskal, Prim and many more.."
     }
 }
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index e462441..407f871 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
-<!-- PHPUnit configuration file with new format for PHPUnit 9.3+ -->
-<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
-         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd"
+<!-- PHPUnit configuration file with new format for PHPUnit 9.5+ -->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.5/phpunit.xsd"
          bootstrap="vendor/autoload.php"
          cacheResult="false"
          colors="true"
@@ -19,5 +19,10 @@
     </coverage>
     <php>
         <ini name="error_reporting" value="-1" />
+        <!-- Evaluate assertions, requires running with "php -d zend.assertions=1 vendor/bin/phpunit" -->
+        <!-- <ini name="zend.assertions=1" value="1" /> -->
+        <ini name="assert.active" value="1" />
+        <ini name="assert.exception" value="1" />
+        <ini name="assert.bail" value="0" />
     </php>
 </phpunit>
diff --git a/phpunit.xml.legacy b/phpunit.xml.legacy
index 44030e2..bf31c92 100644
--- a/phpunit.xml.legacy
+++ b/phpunit.xml.legacy
@@ -15,4 +15,12 @@
             <directory>./src/</directory>
         </whitelist>
     </filter>
+    <php>
+        <ini name="error_reporting" value="-1" />
+        <!-- Evaluate assertions, requires running with "php -d zend.assertions=1 vendor/bin/phpunit" -->
+        <!-- <ini name="zend.assertions=1" value="1" /> -->
+        <ini name="assert.active" value="1" />
+        <ini name="assert.exception" value="1" />
+        <ini name="assert.bail" value="0" />
+    </php>
 </phpunit>