// alone
    assertThat(segment.removeFromChainForTesting(entryOne, entryOne)).isNull();

    // head
    assertSame(entryOne, segment.removeFromChainForTesting(entryTwo, entryTwo));

    // middle
    InternalEntry<Object, Object, ?> newFirst =
        segment.removeFromChainForTesting(entryThree, entryTwo);
    assertSame(keyThree, newFirst.getKey());

    // alone
    assertThat(segment.removeFromChainForTesting(entryOne, entryOne)).isNull();

    // head
    assertSame(entryOne, segment.removeFromChainForTesting(entryTwo, entryTwo));

    // middle
    InternalEntry<Object, Object, ?> newFirst =
        segment.removeFromChainForTesting(entryThree, entryTwo);
    assertSame(keyThree, newFirst.getKey());

      return removeEntryForTesting(castForTesting(entry));
    }

    /** Unsafely removes the given entry from the given chain in this segment's hash table. */
    @Nullable E removeFromChainForTesting(
        InternalEntry<K, V, ?> first, InternalEntry<K, V, ?> entry) {
      return removeFromChain(castForTesting(first), castForTesting(entry));
    }

    /**