TestChunkEncoder

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package org.apache.hc.core5.http.impl.nio;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;

import org.apache.hc.core5.http.WritableByteChannelMock;
import org.apache.hc.core5.http.impl.BasicHttpTransportMetrics;
import org.apache.hc.core5.http.message.BasicHeader;
import org.apache.hc.core5.http.nio.SessionOutputBuffer;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
import org.mockito.ArgumentMatchers;
import org.mockito.Mockito;

/**
 * Simple tests for {@link ChunkEncoder}.
 */
public class TestChunkEncoder {

    @Test
    public void testBasicCoding() throws Exception {
        final WritableByteChannelMock channel = new WritableByteChannelMock(64);
        final SessionOutputBuffer outbuf = new SessionOutputBufferImpl(1024, 128);
        final BasicHttpTransportMetrics metrics = new BasicHttpTransportMetrics();
        final ChunkEncoder encoder = new ChunkEncoder(channel, outbuf, metrics);

        encoder.write(CodecTestUtils.wrap("12345"));
        encoder.write(CodecTestUtils.wrap("678"));
        encoder.write(CodecTestUtils.wrap("90"));
        encoder.complete();

        outbuf.flush(channel);

        final String s = channel.dump(StandardCharsets.US_ASCII);

        Assertions.assertTrue(encoder.isCompleted());
        Assertions.assertEquals("5\r\n12345\r\n3\r\n678\r\n2\r\n90\r\n0\r\n\r\n", s);
        Assertions.assertEquals("[chunk-coded; completed: true]", encoder.toString());
    }

    @Test
    public void testChunkNoExceed() throws Exception {
        final WritableByteChannelMock channel = new WritableByteChannelMock(64);
        final SessionOutputBuffer outbuf = new SessionOutputBufferImpl(1024, 16);
        final BasicHttpTransportMetrics metrics = new BasicHttpTransportMetrics();
        final ChunkEncoder encoder = new ChunkEncoder(channel, outbuf, metrics);
        encoder.write(CodecTestUtils.wrap("1234"));
        encoder.complete();

        outbuf.flush(channel);

        final String s = channel.dump(StandardCharsets.US_ASCII);

        Assertions.assertTrue(encoder.isCompleted());
        Assertions.assertEquals("4\r\n1234\r\n0\r\n\r\n", s);
    }

    @Test // See HTTPCORE-239
    public void testLimitedChannel() throws Exception {
        final WritableByteChannelMock channel = new WritableByteChannelMock(16, 16);
        final SessionOutputBuffer outbuf = new SessionOutputBufferImpl(16, 16);
        final BasicHttpTransportMetrics metrics = new BasicHttpTransportMetrics();
        final ChunkEncoder encoder = new ChunkEncoder(channel, outbuf, metrics);

        // fill up the channel
        channel.write(CodecTestUtils.wrap("0123456789ABCDEF"));
        // fill up the out buffer
        outbuf.write(CodecTestUtils.wrap("0123456789ABCDEF"));

        final ByteBuffer src = CodecTestUtils.wrap("0123456789ABCDEF");
        Assertions.assertEquals(0, encoder.write(src));
        Assertions.assertEquals(0, encoder.write(src));
        Assertions.assertEquals(0, encoder.write(src));

        // should not be able to copy any bytes, until we flush the channel and buffer
        channel.reset();
        outbuf.flush(channel);
        channel.reset();

        Assertions.assertEquals(10, encoder.write(src));
        channel.flush();
        Assertions.assertEquals(6, encoder.write(src));
        channel.flush();
        Assertions.assertEquals(0, encoder.write(src));

        outbuf.flush(channel);
        final String s = channel.dump(StandardCharsets.US_ASCII);
        Assertions.assertEquals("4\r\n0123\r\n4\r\n4567\r\n2\r\n89\r\n4\r\nABCD\r\n2\r\nEF\r\n", s);
    }

    @Test
    public void testBufferFragments() throws Exception {
        final WritableByteChannelMock channel = Mockito.spy(new WritableByteChannelMock(1024));
        final SessionOutputBuffer outbuf = new SessionOutputBufferImpl(1024, 1024);
        final BasicHttpTransportMetrics metrics = new BasicHttpTransportMetrics();
        final ChunkEncoder encoder = new ChunkEncoder(channel, outbuf, metrics, 1024);

        Assertions.assertEquals(16, encoder.write(CodecTestUtils.wrap("0123456789ABCDEF")));
        Assertions.assertEquals(16, encoder.write(CodecTestUtils.wrap("0123456789ABCDEF")));
        Assertions.assertEquals(16, encoder.write(CodecTestUtils.wrap("0123456789ABCDEF")));

        Mockito.verify(channel, Mockito.never()).write(ArgumentMatchers.any());

        outbuf.flush(channel);
        final String s = channel.dump(StandardCharsets.US_ASCII);
        Assertions.assertEquals("10\r\n0123456789ABCDEF\r\n10\r\n0123456789ABCDEF\r\n" +
                "10\r\n0123456789ABCDEF\r\n", s);
    }

    @Test
    public void testChunkExceed() throws Exception {
        final WritableByteChannelMock channel = new WritableByteChannelMock(64);
        final SessionOutputBuffer outbuf = new SessionOutputBufferImpl(16, 16);
        final BasicHttpTransportMetrics metrics = new BasicHttpTransportMetrics();
        final ChunkEncoder encoder = new ChunkEncoder(channel, outbuf, metrics);

        final ByteBuffer src = CodecTestUtils.wrap("0123456789ABCDEF");

        Assertions.assertEquals(16, encoder.write(src));
        Assertions.assertEquals(0, src.remaining());

        outbuf.flush(channel);
        final String s = channel.dump(StandardCharsets.US_ASCII);
        Assertions.assertEquals("4\r\n0123\r\n4\r\n4567\r\n4\r\n89AB\r\n4\r\nCDEF\r\n", s);

    }

    @Test
    public void testCodingEmptyBuffer() throws Exception {
        final WritableByteChannelMock channel = new WritableByteChannelMock(64);
        final SessionOutputBuffer outbuf = new SessionOutputBufferImpl(1024, 128);
        final BasicHttpTransportMetrics metrics = new BasicHttpTransportMetrics();
        final ChunkEncoder encoder = new ChunkEncoder(channel, outbuf, metrics);

        encoder.write(CodecTestUtils.wrap("12345"));
        encoder.write(CodecTestUtils.wrap("678"));
        encoder.write(CodecTestUtils.wrap("90"));

        final ByteBuffer empty = ByteBuffer.allocate(100);
        empty.flip();
        encoder.write(empty);
        encoder.write(null);

        encoder.complete();

        outbuf.flush(channel);

        final String s = channel.dump(StandardCharsets.US_ASCII);

        Assertions.assertTrue(encoder.isCompleted());
        Assertions.assertEquals("5\r\n12345\r\n3\r\n678\r\n2\r\n90\r\n0\r\n\r\n", s);
    }

    @Test
    public void testCodingCompleted() throws Exception {
        final WritableByteChannelMock channel = new WritableByteChannelMock(64);
        final SessionOutputBuffer outbuf = new SessionOutputBufferImpl(1024, 128);
        final BasicHttpTransportMetrics metrics = new BasicHttpTransportMetrics();
        final ChunkEncoder encoder = new ChunkEncoder(channel, outbuf, metrics);

        encoder.write(CodecTestUtils.wrap("12345"));
        encoder.write(CodecTestUtils.wrap("678"));
        encoder.write(CodecTestUtils.wrap("90"));
        encoder.complete();

        Assertions.assertThrows(IllegalStateException.class, () -> encoder.write(CodecTestUtils.wrap("more stuff")));
        Assertions.assertThrows(IllegalStateException.class, () -> encoder.complete());
    }

    @Test
    public void testInvalidConstructor() {
        final WritableByteChannelMock channel = new WritableByteChannelMock(64);
        final SessionOutputBuffer outbuf = new SessionOutputBufferImpl(1024, 128);

        Assertions.assertThrows(NullPointerException.class, () -> new ChunkEncoder(null, null, null));
        Assertions.assertThrows(NullPointerException.class, () -> new ChunkEncoder(channel, null, null));
        Assertions.assertThrows(NullPointerException.class, () -> new ChunkEncoder(channel, outbuf, null));
    }

    @Test
    public void testTrailers() throws IOException {
        final WritableByteChannelMock channel = new WritableByteChannelMock(64);
        final SessionOutputBuffer outbuf = new SessionOutputBufferImpl(1024, 128);
        final BasicHttpTransportMetrics metrics = new BasicHttpTransportMetrics();
        final ChunkEncoder encoder = new ChunkEncoder(channel, outbuf, metrics, 0);
        encoder.write(CodecTestUtils.wrap("1"));
        encoder.write(CodecTestUtils.wrap("23"));
        encoder.complete(Arrays.asList(new BasicHeader("E", ""), new BasicHeader("Y", "Z")));

        outbuf.flush(channel);

        final String s = channel.dump(StandardCharsets.US_ASCII);

        Assertions.assertTrue(encoder.isCompleted());
        Assertions.assertEquals("1\r\n1\r\n2\r\n23\r\n0\r\nE: \r\nY: Z\r\n\r\n", s);
        Assertions.assertEquals("[chunk-coded; completed: true]", encoder.toString());
    }
}