mc-protocol/src/test/java/mc/protocol/io/NetOutputStreamTest.java

package mc.protocol.io;

import org.apache.commons.lang3.RandomStringUtils;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.Arguments;
import org.junit.jupiter.params.provider.MethodSource;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.Random;
import java.util.UUID;
import java.util.stream.Stream;

import static org.junit.jupiter.api.Assertions.assertArrayEquals;
import static org.junit.jupiter.api.Assertions.assertEquals;

class NetOutputStreamTest {

    private static Random random;

    @BeforeAll
    static void setUp() {
        random = new Random(System.currentTimeMillis());
    }

    @ParameterizedTest
    @MethodSource("paramsWriteBoolean")
    void writeBoolean(boolean sourceValue, byte expectedByte) {
        NetOutputStream netOutputStream = createNetOutputStream();
        netOutputStream.writeBoolean(sourceValue);

        assertEquals(expectedByte, toByteArray(netOutputStream)[0]);
    }

    @ParameterizedTest
    @MethodSource("paramsWriteByte")
    void writeByte(byte sourceValue, byte expectedByte) throws IOException {
        NetOutputStream netOutputStream = createNetOutputStream();
        netOutputStream.writeByte(sourceValue);

        assertEquals(expectedByte, toByteArray(netOutputStream)[0]);

        netOutputStream = createNetOutputStream();
        netOutputStream.write(sourceValue);

        assertEquals(expectedByte, toByteArray(netOutputStream)[0]);
    }

    @ParameterizedTest
    @MethodSource("paramsWriteString")
    void writeString(String string) {
        NetOutputStream netOutputStream = createNetOutputStream();
        netOutputStream.writeString(string);

        byte[] bytes = toByteArray(netOutputStream);
        int length = bytes[0];
        assertEquals(string.codePoints().count(), length);

        byte[] dataBytes = new byte[bytes.length - 1];
        System.arraycopy(bytes, 1, dataBytes, 0, dataBytes.length);
        assertEquals(string, new String(dataBytes, StandardCharsets.UTF_8));
    }

    @Test
    void writeString_overSize() {
        String overSizeString = RandomStringUtils.randomAscii(Short.MAX_VALUE + Short.MAX_VALUE);
        NetOutputStream netOutputStream = createNetOutputStream();
        netOutputStream.writeString(overSizeString);

        NetInputStream netInputStream = new ByteArrayNetInputStream(toByteArray(netOutputStream));
        String actualString = netInputStream.readString();

        String expectedString = overSizeString.substring(0, Short.MAX_VALUE);

        assertEquals(expectedString, actualString);
    }

    @ParameterizedTest
    @MethodSource("paramsWriteVarInt")
    void writeVarInt(int sourceValue, byte[] expectedBytes) {
        NetOutputStream netOutputStream = createNetOutputStream();
        netOutputStream.writeVarInt(sourceValue);

        assertArrayEquals(expectedBytes, toByteArray(netOutputStream));
    }

    @ParameterizedTest
    @MethodSource({"paramsWriteVarInt", "paramsWriteVarLong"})
    void writeVarLong(long sourceValue, byte[] expectedBytes) {
        NetOutputStream netOutputStream = createNetOutputStream();
        netOutputStream.writeVarLong(sourceValue);

        assertArrayEquals(expectedBytes, toByteArray(netOutputStream));
    }

    @Test
    void writeUUID() {
        final UUID uuid = UUID.randomUUID();

        NetOutputStream netOutputStream = createNetOutputStream();
        netOutputStream.writeUUID(uuid);

        final long mostSignificantBits = uuid.getMostSignificantBits();
        final long leastSignificantBits = uuid.getLeastSignificantBits();

        assertArrayEquals(new byte[]{ (byte) ((mostSignificantBits >>> 56) & 0xFF),
                        (byte) ((mostSignificantBits >>> 48) & 0xFF),
                        (byte) ((mostSignificantBits >>> 40) & 0xFF),
                        (byte) ((mostSignificantBits >>> 32) & 0xFF),
                        (byte) ((mostSignificantBits >>> 24) & 0xFF),
                        (byte) ((mostSignificantBits >>> 16) & 0xFF),
                        (byte) ((mostSignificantBits >>> 8) & 0xFF),
                        (byte) (mostSignificantBits & 0xFF),

                        (byte) ((leastSignificantBits >>> 56) & 0xFF),
                        (byte) ((leastSignificantBits >>> 48) & 0xFF),
                        (byte) ((leastSignificantBits >>> 40) & 0xFF),
                        (byte) ((leastSignificantBits >>> 32) & 0xFF),
                        (byte) ((leastSignificantBits >>> 24) & 0xFF),
                        (byte) ((leastSignificantBits >>> 16) & 0xFF),
                        (byte) ((leastSignificantBits >>> 8) & 0xFF),
                        (byte) (leastSignificantBits & 0xFF) },
                toByteArray(netOutputStream));
    }

    @Test
    void writeBytes() throws IOException {
        byte[] bytes = new byte[128];
        random.nextBytes(bytes);
        NetOutputStream netOutputStream = createNetOutputStream();
        netOutputStream.writeBytes(bytes);

        assertArrayEquals(bytes, toByteArray(netOutputStream));

        netOutputStream = createNetOutputStream();
        netOutputStream.write(bytes);

        assertArrayEquals(bytes, toByteArray(netOutputStream));
    }

    @Test
    void write_offset() throws IOException {
        byte[] bytes = new byte[128];
        random.nextBytes(bytes);
        NetOutputStream netOutputStream = createNetOutputStream();
        netOutputStream.write(bytes, 3, 11);

        byte[] actualBytes = new byte[11];
        System.arraycopy(toByteArray(netOutputStream), 0, actualBytes, 0, 11);

        byte[] expectedBytes = new byte[11];
        System.arraycopy(bytes, 3, expectedBytes, 0, 11);

        assertArrayEquals(expectedBytes, actualBytes);
    }

    private NetOutputStream createNetOutputStream() {
        return new ByteArrayNetOutputStream();
    }

    private byte[] toByteArray(NetOutputStream netOutputStream) {
        return ((ByteArrayNetOutputStream) netOutputStream).toByteArray();
    }

    private static Stream<Arguments> paramsWriteBoolean() {
        return Stream.of(
                Arguments.of(false, (byte) 0x00),
                Arguments.of(true, (byte) 0x01)
        );
    }

    private static Stream<Arguments> paramsWriteByte() {
        byte b = Integer.valueOf(random.nextInt()).byteValue();

        return Stream.of(
                Arguments.of(b, b),
                Arguments.of((byte) 128, (byte) -128)
        );
    }

    private static Stream<Arguments> paramsWriteString() {
        return Stream.of(
                Arguments.of(""),
                Arguments.of("Latin"),
                Arguments.of("Кириллица"),
                Arguments.of("العربية"),
                Arguments.of("ﬦﬣﬡ"), // Алфавитные формы представления
                Arguments.of("\uD800\uDD07") // Эгейские цифры, [один]
        );
    }

    private static Stream<Arguments> paramsWriteVarInt() {
        return Stream.of(
                Arguments.of(120, new byte[]{ 0x78 }),
                Arguments.of(12000, new byte[]{ (byte) 0xE0, 0x5D }),
                Arguments.of(120000, new byte[]{ (byte) 0xC0, (byte) 0xA9, 0x07 }),
                Arguments.of(120000000, new byte[]{ (byte) 0x80, (byte) 0x9C, (byte) 0x9C, (byte) 0x39 }),
                Arguments.of(1200000000, new byte[]{ (byte) 0x80, (byte) 0x98, (byte) 0x9A, (byte) 0xBC, 0x04 })
        );
    }

    private static Stream<Arguments> paramsWriteVarLong() {
        return Stream.of(
                Arguments.of(
                        12_000_000_000L,
                        new byte[]{ (byte) 0x80, (byte) 0xF0, (byte) 0x85, (byte) 0xDA, 0x2C }),
                Arguments.of(
                        120_000_000_000L,
                        new byte[]{ (byte) 0x80, (byte) 0xE0, (byte) 0xBA, (byte) 0x84, (byte) 0xBF, 0x03 }),
                Arguments.of(
                        12_000_000_000_000L,
                        new byte[]{ (byte) 0x80, (byte) 0x80, (byte) 0xF3, (byte) 0xBD, (byte) 0x9F, (byte) 0xDD,
                                0x02 }),
                Arguments.of(
                        1_200_000_000_000_000L,
                        new byte[]{ (byte) 0x80, (byte) 0x80, (byte) 0xEC, (byte) 0xAD, (byte) 0xCC, (byte) 0xEC,
                                (byte) 0x90, 0x02}),
                Arguments.of(
                        120_000_000_000_000_000L,
                        new byte[]{ (byte) 0x80, (byte) 0x80, (byte) 0xB0, (byte) 0xE8, (byte) 0xD3, (byte) 0xEB,
                                (byte) 0x94, (byte) 0xD5, 0x01 }),
                Arguments.of(
                        Long.MIN_VALUE,
                        new byte[]{ (byte) 0x80, (byte) 0x80, (byte) 0x80, (byte) 0x80, (byte) 0x80, (byte) 0x80,
                                (byte) 0x80, (byte) 0x80, (byte) 0x80, 0x01 })
        );
    }
}