smallerMap.remove(smallerMap.keySet().iterator().next());
    } catch (UnsupportedOperationException e) {
      return;
    }

    assertFalse(map.equals(smallerMap));
  }

  public void testEqualsForEmptyMap() {
    Map<K, V> map;
    try {
      map = makeEmptyMap();
    } catch (UnsupportedOperationException e) {
      return;
    }

    // Explicitly call `equals`; `assertEquals` might return fast