diff --git a/phpunit.xml b/phpunit.xml
index abfc1d43..bd29d74c 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -27,6 +27,8 @@
         <env name="CLASSIFICATION_PROVIDER" value="deterministic" force="true"/>
         <env name="CONTENT_SCORE_PROVIDER" value="deterministic" force="true"/>
         <env name="OPENAI_API_KEY" value="" force="true"/>
+        <!-- Fester Test-Schlüssel: die Suite hängt nicht vom lokalen APP_KEY ab (nicht geheim, nur für Tests). -->
+        <env name="APP_KEY" value="base64:VoIaiZvNh62alaGep69H4qDL3dI+gkLPfXxtoC68clU=" force="true"/>
         <env name="DB_CONNECTION" value="sqlite" force="true"/>
         <env name="DB_DATABASE" value=":memory:" force="true"/>
         <server name="DB_CONNECTION" value="sqlite" force="true"/>