Index: trunk/test/unit/org/openstreetmap/josm/data/projection/SwissGridTest.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/data/projection/SwissGridTest.java	(revision 6246)
+++ trunk/test/unit/org/openstreetmap/josm/data/projection/SwissGridTest.java	(revision 6264)
@@ -48,12 +48,12 @@
     public void projReferenceTest() {
         Projection swiss = Projections.getProjectionByCode("EPSG:21781"); // Swiss grid
-        String errs = "";
+        StringBuilder errs = new StringBuilder();
         for (ProjData pd : data) {
             EastNorth en2 = swiss.latlon2eastNorth(pd.ll);
             if (Math.abs(pd.en.east() - en2.east()) > EPSILON || Math.abs(pd.en.north() - en2.north()) > EPSILON) {
-                errs += String.format("%s should be: %s but is: %s\n", pd.name, pd.en, en2);
-            }
-        }
-        assertTrue(errs, errs.length() == 0);
+                errs.append(String.format("%s should be: %s but is: %s\n", pd.name, pd.en, en2));
+            }
+        }
+        assertTrue(errs.toString(), errs.length() == 0);
     }