Index: trunk/build.xml
===================================================================
--- trunk/build.xml	(revision 3579)
+++ trunk/build.xml	(revision 3580)
@@ -172,4 +172,5 @@
 		<junit printsummary="yes">
 			<sysproperty key="josm.home" value="${test.dir}/config/unit-josm.home"/>
+			<sysproperty key="java.awt.headless" value="true"/>
 			<classpath>
 				<path refid="test.classpath"/>