Index: trunk/test/unit/org/openstreetmap/josm/plugins/PluginHandlerTestIT.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/plugins/PluginHandlerTestIT.java	(revision 18260)
+++ trunk/test/unit/org/openstreetmap/josm/plugins/PluginHandlerTestIT.java	(revision 18267)
@@ -195,4 +195,15 @@
                 if (pi.getRequiredPlugins().contains("javafx")) {
                     System.out.println("Ignoring " + pi.name + " (requiring JavaFX and we're using Java < 11 in headless mode)");
+                    it.remove();
+                }
+            }
+        }
+
+        // Skip unofficial plugins in headless mode, too much work for us for little added-value
+        if (GraphicsEnvironment.isHeadless()) {
+            for (Iterator<PluginInformation> it = plugins.iterator(); it.hasNext();) {
+                PluginInformation pi = it.next();
+                if (pi.isExternal()) {
+                    System.out.println("Ignoring " + pi.name + " (unofficial plugin in headless mode)");
                     it.remove();
                 }