@@ -0,0 +1,690 @@
+package com.fasterxml.jackson.failing;%0A%0Aimport java.util.*;%0A%0Aimport com.fasterxml.jackson.databind.*;%0A%0Apublic class KeySerializers1679Test extends BaseMapTest%0A%7B%0A    /*%0A    /**********************************************************%0A    /* Unit tests%0A    /**********************************************************%0A     */%0A%0A    private final ObjectMapper MAPPER = new ObjectMapper();%0A%0A    // %5Bdatabind#1679%5D%0A    public void testRecursion1679() throws Exception%0A    %7B%0A        Map%3CObject, Object%3E objectMap = new HashMap%3CObject, Object%3E();%0A        objectMap.put(new Object(), new Object());%0A        String json = MAPPER.writeValueAsString(objectMap);%0A        assertEquals(%22%7B%7D%22, json);%0A    %7D%0A%7D%0A

Add failing test for #1679