From 4009fe3a05caaf45ec230fbedc29dbe5d9b7f412 Mon Sep 17 00:00:00 2001
From: Tatu Saloranta <tatu.saloranta@iki.fi>
Date: Tue, 27 Jun 2017 10:33:01 -0700
Subject: [PATCH] Add failing test for #1679

---
 .../failing/KeySerializers1679Test.java       | 25 +++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 src/test/java/com/fasterxml/jackson/failing/KeySerializers1679Test.java

diff --git a/src/test/java/com/fasterxml/jackson/failing/KeySerializers1679Test.java b/src/test/java/com/fasterxml/jackson/failing/KeySerializers1679Test.java
new file mode 100644
index 0000000000..095be8595d
--- /dev/null
+++ b/src/test/java/com/fasterxml/jackson/failing/KeySerializers1679Test.java
@@ -0,0 +1,25 @@
+package com.fasterxml.jackson.failing;
+
+import java.util.*;
+
+import com.fasterxml.jackson.databind.*;
+
+public class KeySerializers1679Test extends BaseMapTest
+{
+    /*
+    /**********************************************************
+    /* Unit tests
+    /**********************************************************
+     */
+
+    private final ObjectMapper MAPPER = new ObjectMapper();
+
+    // [databind#1679]
+    public void testRecursion1679() throws Exception
+    {
+        Map<Object, Object> objectMap = new HashMap<Object, Object>();
+        objectMap.put(new Object(), new Object());
+        String json = MAPPER.writeValueAsString(objectMap);
+        assertEquals("{}", json);
+    }
+}