protected Map<String, Integer> makeEmptyMap() {
    throw new UnsupportedOperationException();
  }

  @Override
  Table<String, Character, Integer> makeTable() {
    return ArrayTable.create(asList("one", "two", "three", "four"), asList('a', 'b', 'c'));
  }

    throw new UnsupportedOperationException();
  }

  @Override
  protected Table<Character, String, Integer> makeTable() {
    return ArrayTable.create(asList('a', 'b', 'c'), asList("one", "two", "three", "four"));
  }

  @Override
  protected Map<String, Integer> makePopulatedMap() {
    Table<Character, String, Integer> table = HashBasedTable.create();
    table.put('a', "one", 2);
    table.put('a', "two", 4);
    table.put('a', "three", 6);
    table.put('b', "four", 8);
    return transformValues(table, TableCollectionTest.DIVIDE_BY_2).row('a');
  }

  }

  @Override
  protected SortedMap<String, Integer> makePopulatedMap() {
    NavigableMap<String, Integer> map = new SafeTreeMap<>();
    map.put("one", 1);
    map.put("two", 2);
    map.put("three", 3);
    return SerializableTester.reserialize(map);
  }

  @Override
  protected SortedMap<String, Integer> makeEmptyMap() throws UnsupportedOperationException {

  @Override
  protected Map<String, Integer> makePopulatedMap() {
    RowSortedTable<Character, String, Integer> table = TreeBasedTable.create();
    table.put('a', "one", 1);
    table.put('a', "two", 2);
    table.put('a', "three", 3);
    table.put('b', "four", 4);
    return unmodifiableRowSortedTable(table).row('a');
  }

  }

  @Override
  protected Map<String, Integer> makePopulatedMap() {
    Table<String, Character, Integer> table = HashBasedTable.create();
    table.put("one", 'a', 1);
    table.put("two", 'a', 2);
    table.put("three", 'a', 3);
    table.put("four", 'b', 4);
    return unmodifiableTable(table).column('a');
  }

  @Override
  public SampleElements<Entry<String, String>> samples() {
    return new SampleElements<>(
        mapEntry("one", "January"),
        mapEntry("two", "February"),
        mapEntry("three", "March"),
        mapEntry("four", "April"),
        mapEntry("five", "May"));
  }

  @Override
  public Map<String, String> create(Object... entries) {
    @SuppressWarnings("unchecked")

    List<Byte> one = Arrays.asList((byte) 1);
    assertThat(Bytes.toArray(one)).isEqualTo(ARRAY1);

    byte[] array = {(byte) 0, (byte) 1, (byte) 0x55};

    List<Byte> three = Arrays.asList((byte) 0, (byte) 1, (byte) 0x55);
    assertThat(Bytes.toArray(three)).isEqualTo(array);

    assertThat(Bytes.toArray(Bytes.asList(array))).isEqualTo(array);
  }

  public void testToArray_threadSafe() {

    public String[] createValueArray(int length) {
      return new String[length];
    }

    @Override
    public SampleElements<String> sampleKeys() {
      return new SampleElements<>("one", "two", "three", "four", "five");
    }

    @Override
    public SampleElements<String> sampleValues() {
      return new SampleElements<>("january", "february", "march", "april", "may");
    }

    @Override

    }

    @Test
    @DisplayName("Should join multiple elements with delimiter")
    void testJoinMultipleElements() {
        String result = StringUtil.join(",", "one", "two", "three", "four");
        assertEquals("one,two,three,four", result);
    }

    @Test
    @DisplayName("Should join with empty string delimiter")
    void testJoinWithEmptyDelimiter() {
        String result = StringUtil.join("", "hello", "world");