Add a (passing) unit test for #1535

Author: cowtowncoder

src/test/java/com/fasterxml/jackson/databind/ser/TestEnumSerialization.java

@@ -412,7 +412,7 @@ public void testEnumMapSerDisableToString() throws Exception {
         m.put(LC749Enum.A, "value");
         assertEquals("{\"A\":\"value\"}", w.writeValueAsString(m));
     }
-    
+
     public void testEnumMapSerEnableToString() throws Exception {
         final ObjectMapper mapper = new ObjectMapper();
         ObjectWriter w = mapper.writer().with(SerializationFeature.WRITE_ENUMS_USING_TO_STRING);
@@ -426,6 +426,13 @@ public void testEnumsWithJsonProperty() throws Exception {
         assertEquals(quote("aleph"), MAPPER.writeValueAsString(EnumWithJsonProperty.A));
     }
 
+    // [databind#1535]
+    public void testEnumKeysWithJsonProperty() throws Exception {
+        Map<EnumWithJsonProperty,Integer> input = new HashMap<EnumWithJsonProperty,Integer>();
+        input.put(EnumWithJsonProperty.A, 13);
+        assertEquals(aposToQuotes("{'aleph':13}"), MAPPER.writeValueAsString(input));
+    }
+
     // [databind#1322]
     public void testEnumsWithJsonPropertyInSet() throws Exception
     {