Index: trunk/test/unit/org/openstreetmap/josm/data/validation/tests/SimilarNamedWaysTest.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/data/validation/tests/SimilarNamedWaysTest.java	(revision 12253)
+++ trunk/test/unit/org/openstreetmap/josm/data/validation/tests/SimilarNamedWaysTest.java	(revision 12283)
@@ -88,4 +88,7 @@
     }
 
+    /**
+     * Test similar names.
+     */
     @Test
     public void testSimilarNames() {
@@ -118,4 +121,10 @@
         checkSimilarity("first and second 2 changes", "First Street", "Soconds Street", true);
         checkSimilarity("first and second 3 changes", "First Street", "Soconds Stret", false);
+
+        // case only, see #14858
+        checkSimilarity("case only", "Rua São João", "Rua Sao Joao", true);
+        checkSimilarity("case only", "Rua São João", "Rua SAO JOAO", true);
+        checkSimilarity("case only", "Rua Sao Joao", "Rua SAO JOAO", true);
+        checkSimilarity("case only", "Rue éèçàïù", "Rue EeCAIU", true);
     }
 }