assertThat(map.replace("bar", 3)).isNull();
    assertEquals(Integer.valueOf(2), map.get("foo"));
    assertFalse(map.containsKey("bar"));
  }

  public void testReplaceConditional() {
    TestMap map = new TestMap();
    map.put("foo", 1);
    assertFalse(map.replace("foo", 2, 3));
    assertFalse(map.replace("bar", 1, 2));
    assertEquals(Integer.valueOf(1), map.get("foo"));