Index: trunk/test/unit/org/openstreetmap/josm/data/osm/TagMapTest.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/data/osm/TagMapTest.java	(revision 18001)
+++ trunk/test/unit/org/openstreetmap/josm/data/osm/TagMapTest.java	(revision 18006)
@@ -3,4 +3,6 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
 
 import org.junit.jupiter.api.Test;
@@ -18,5 +20,9 @@
         assertEquals("TagMap[]", new TagMap().toString());
         assertEquals("TagMap[key=val]", new TagMap(new String[]{"key", "val"}).toString());
-        assertEquals("TagMap[key=val,foo=bar]", new TagMap(new String[]{"key", "val", "foo", "bar"}).toString());
+        TagMap foobar = new TagMap(new String[]{"key", "val", "foo", "bar"});
+        assertEquals("TagMap[key=val,foo=bar]", foobar.toString());
+        assertEquals("TagMap[key=val,foo=bar]", new TagMap(foobar).toString());
+        TagCollection coll = new TagCollection(Arrays.asList(new Tag("a", "b")));
+        assertEquals("TagMap[a=b]", new TagMap(coll).toString());
     }
 }