InternalEntry<Object, Object, ?> copyOne = segment.copyForTesting(entryOne, null);
      assertSame(keyOne, entryOne.getKey());
      assertEquals(hashOne, entryOne.getHash());
      assertNull(entryOne.getNext());
      assertSame(valueOne, copyOne.getValue());

      InternalEntry<Object, Object, ?> copyTwo = segment.copyForTesting(entryTwo, copyOne);
      assertSame(keyTwo, copyTwo.getKey());

      InternalEntry<Object, Object, ?> copyOne = segment.copyForTesting(entryOne, null);
      assertSame(keyOne, entryOne.getKey());
      assertEquals(hashOne, entryOne.getHash());
      assertNull(entryOne.getNext());
      assertSame(valueOne, copyOne.getValue());

      InternalEntry<Object, Object, ?> copyTwo = segment.copyForTesting(entryTwo, copyOne);
      assertSame(keyTwo, copyTwo.getKey());

     */
    void setTableEntryForTesting(int i, InternalEntry<K, V, ?> entry) {
      table.set(i, castForTesting(entry));
    }

    /** Unsafely returns a copy of the given entry. */
    E copyForTesting(InternalEntry<K, V, ?> entry, @Nullable InternalEntry<K, V, ?> newNext) {
      return this.map.entryHelper.copy(self(), castForTesting(entry), castForTesting(newNext));
    }