TestFifoBuffer.java

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package org.apache.hc.core5.http2.hpack;

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;

class TestFifoBuffer {

    @Test
    void testAddRemoveCycle() {

        final FifoBuffer fifoBuffer = new FifoBuffer(5);

        final HPackHeader h1 = new HPackHeader("h", "1");
        final HPackHeader h2 = new HPackHeader("h", "2");
        final HPackHeader h3 = new HPackHeader("h", "3");
        final HPackHeader h4 = new HPackHeader("h", "4");

        for (int i = 0; i < 20; i++) {
            Assertions.assertEquals(0, fifoBuffer.size());
            Assertions.assertSame(null, fifoBuffer.getFirst());
            Assertions.assertSame(null, fifoBuffer.getLast());
            fifoBuffer.addFirst(h1);
            Assertions.assertSame(h1, fifoBuffer.getFirst());
            Assertions.assertSame(h1, fifoBuffer.getLast());
            Assertions.assertEquals(1, fifoBuffer.size());
            fifoBuffer.addFirst(h2);
            Assertions.assertEquals(2, fifoBuffer.size());
            Assertions.assertSame(h2, fifoBuffer.getFirst());
            Assertions.assertSame(h1, fifoBuffer.getLast());
            fifoBuffer.addFirst(h3);
            Assertions.assertEquals(3, fifoBuffer.size());
            Assertions.assertSame(h3, fifoBuffer.getFirst());
            Assertions.assertSame(h1, fifoBuffer.getLast());
            fifoBuffer.addFirst(h4);
            Assertions.assertEquals(4, fifoBuffer.size());
            Assertions.assertSame(h4, fifoBuffer.getFirst());
            Assertions.assertSame(h1, fifoBuffer.getLast());

            Assertions.assertSame(h4, fifoBuffer.get(0));
            Assertions.assertSame(h3, fifoBuffer.get(1));
            Assertions.assertSame(h2, fifoBuffer.get(2));
            Assertions.assertSame(h1, fifoBuffer.get(3));

            fifoBuffer.removeLast();
            Assertions.assertEquals(3, fifoBuffer.size());
            Assertions.assertSame(h4, fifoBuffer.getFirst());
            Assertions.assertSame(h2, fifoBuffer.getLast());
            fifoBuffer.removeLast();
            Assertions.assertEquals(2, fifoBuffer.size());
            Assertions.assertSame(h4, fifoBuffer.getFirst());
            Assertions.assertSame(h3, fifoBuffer.getLast());
            fifoBuffer.removeLast();
            Assertions.assertEquals(1, fifoBuffer.size());
            Assertions.assertSame(h4, fifoBuffer.getFirst());
            Assertions.assertSame(h4, fifoBuffer.getLast());
            fifoBuffer.removeLast();
            Assertions.assertEquals(0, fifoBuffer.size());
            Assertions.assertSame(null, fifoBuffer.getFirst());
            Assertions.assertSame(null, fifoBuffer.getLast());
        }
    }

    @Test
    void testExpand() {

        final HPackHeader h1 = new HPackHeader("h", "1");
        final HPackHeader h2 = new HPackHeader("h", "2");
        final HPackHeader h3 = new HPackHeader("h", "3");
        final HPackHeader h4 = new HPackHeader("h", "4");

        for (int i = 0; i < 10; i++) {

            final FifoBuffer fifoBuffer = new FifoBuffer(1);

            for (int n = 0; n < i; n++) {

                fifoBuffer.addFirst(h1);
                fifoBuffer.removeLast();
            }

            Assertions.assertEquals(0, fifoBuffer.size());
            Assertions.assertSame(null, fifoBuffer.getFirst());
            Assertions.assertSame(null, fifoBuffer.getLast());
            fifoBuffer.addFirst(h1);
            Assertions.assertSame(h1, fifoBuffer.getFirst());
            Assertions.assertSame(h1, fifoBuffer.getLast());
            Assertions.assertEquals(1, fifoBuffer.size());
            fifoBuffer.addFirst(h2);
            Assertions.assertEquals(2, fifoBuffer.size());
            Assertions.assertSame(h2, fifoBuffer.getFirst());
            Assertions.assertSame(h1, fifoBuffer.getLast());
            fifoBuffer.addFirst(h3);
            Assertions.assertEquals(3, fifoBuffer.size());
            Assertions.assertSame(h3, fifoBuffer.getFirst());
            Assertions.assertSame(h1, fifoBuffer.getLast());
            fifoBuffer.addFirst(h4);
            Assertions.assertEquals(4, fifoBuffer.size());
            Assertions.assertSame(h4, fifoBuffer.getFirst());
            Assertions.assertSame(h1, fifoBuffer.getLast());

            Assertions.assertSame(h4, fifoBuffer.get(0));
            Assertions.assertSame(h3, fifoBuffer.get(1));
            Assertions.assertSame(h2, fifoBuffer.get(2));
            Assertions.assertSame(h1, fifoBuffer.get(3));
        }
    }

}