"1::2::3::4:5",
            "::7:6:5:4:3:2:", // should end with ":0"
            ":6:5:4:3:2:1::", // should begin with "0:"
            "2001::db:::1",
            "FEDC:9878",
            "+1.+2.+3.4",
            "1.2.3.4e0",
            "6:5:4:3:2:1:0", // too few parts
            "::7:6:5:4:3:2:1:0", // too many parts
            "7:6:5:4:3:2:1:0::", // too many parts
            "9:8:7:6:5:4:3::2:1", // too many parts

    ByteArrayDataOutput out = ByteStreams.newDataOutput();
    out.writeInt(0x12345678);
    out.writeInt(0x76543210);
    assertThat(out.toByteArray()).isEqualTo(bytes);
  }

  public void testNewDataOutput_sized() {
    ByteArrayDataOutput out = ByteStreams.newDataOutput(4);
    out.writeInt(0x12345678);
    out.writeInt(0x76543210);
    assertThat(out.toByteArray()).isEqualTo(bytes);
  }

    ByteArrayDataOutput out = ByteStreams.newDataOutput();
    out.writeInt(0x12345678);
    out.writeInt(0x76543210);
    assertThat(out.toByteArray()).isEqualTo(bytes);
  }

  public void testNewDataOutput_sized() {
    ByteArrayDataOutput out = ByteStreams.newDataOutput(4);
    out.writeInt(0x12345678);
    out.writeInt(0x76543210);
    assertThat(out.toByteArray()).isEqualTo(bytes);
  }

        StringBuilder buf = new StringBuilder();
        Supplier<Object> supplier = () -> Long.valueOf(9876543210L);

        monitorTarget.append(buf, "longKey", supplier);
        assertEquals("\"longKey\":9876543210", buf.toString());
    }

    // Test append method with Short value
    @Test
    public void test_append_shortValue() {
        StringBuilder buf = new StringBuilder();