diff --git a/src/tests/antunit/filters/native2ascii-test.xml b/src/tests/antunit/filters/native2ascii-test.xml
index 37074a434..26fa0c786 100644
--- a/src/tests/antunit/filters/native2ascii-test.xml
+++ b/src/tests/antunit/filters/native2ascii-test.xml
@@ -23,7 +23,7 @@
       <resourcesmatch>
         <string value="\u00e4\u00f6\u00fc=\u00c4\u00d6\u00dc
 \u00df=\u20ac"/>
-        <concat>
+        <concat encoding="UTF-8" outputencoding="UTF-8">
           <string value="äöü=ÄÖÜ
 ß=€"/>
           <filterchain>
@@ -39,7 +39,7 @@
       <resourcesmatch>
         <string value="äöü=ÄÖÜ
 ß=€"/>
-        <concat>
+        <concat encoding="UTF-8" outputencoding="UTF-8">
           <string value="\u00e4\u00f6\u00fc=\u00c4\u00d6\u00dc
 \u00df=\u20ac"/>
           <filterchain>