TestFifoLinkedList.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 TestFifoLinkedList {

    @Test
    void testAddRemoveCycle() {

        final FifoLinkedList fifoLinkedList = new FifoLinkedList();

        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 < 5; i++) {
            Assertions.assertEquals(0, fifoLinkedList.size());
            Assertions.assertSame(null, fifoLinkedList.getFirst());
            Assertions.assertSame(null, fifoLinkedList.getLast());

            fifoLinkedList.addFirst(h1);
            Assertions.assertEquals(1, fifoLinkedList.size());
            Assertions.assertSame(h1, fifoLinkedList.getFirst());
            Assertions.assertSame(h1, fifoLinkedList.getLast());

            fifoLinkedList.addFirst(h2);
            Assertions.assertEquals(2, fifoLinkedList.size());
            Assertions.assertSame(h2, fifoLinkedList.getFirst());
            Assertions.assertSame(h1, fifoLinkedList.getLast());

            fifoLinkedList.addFirst(h3);
            Assertions.assertEquals(3, fifoLinkedList.size());
            Assertions.assertSame(h3, fifoLinkedList.getFirst());
            Assertions.assertSame(h1, fifoLinkedList.getLast());

            fifoLinkedList.addFirst(h4);
            Assertions.assertEquals(4, fifoLinkedList.size());
            Assertions.assertSame(h4, fifoLinkedList.getFirst());
            Assertions.assertSame(h1, fifoLinkedList.getLast());

            fifoLinkedList.removeLast();
            Assertions.assertEquals(3, fifoLinkedList.size());
            Assertions.assertSame(h4, fifoLinkedList.getFirst());
            Assertions.assertSame(h2, fifoLinkedList.getLast());

            fifoLinkedList.removeLast();
            Assertions.assertEquals(2, fifoLinkedList.size());
            Assertions.assertSame(h4, fifoLinkedList.getFirst());
            Assertions.assertSame(h3, fifoLinkedList.getLast());

            fifoLinkedList.removeLast();
            Assertions.assertEquals(1, fifoLinkedList.size());
            Assertions.assertSame(h4, fifoLinkedList.getFirst());
            Assertions.assertSame(h4, fifoLinkedList.getLast());

            fifoLinkedList.removeLast();
            Assertions.assertEquals(0, fifoLinkedList.size());
            Assertions.assertSame(null, fifoLinkedList.getFirst());
            Assertions.assertSame(null, fifoLinkedList.getLast());
        }
    }

    @Test
    void testGetIndex() {

        final FifoLinkedList fifoLinkedList = new FifoLinkedList();

        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");

        final FifoLinkedList.InternalNode node1 = fifoLinkedList.addFirst(h1);
        final FifoLinkedList.InternalNode node2 = fifoLinkedList.addFirst(h2);
        final FifoLinkedList.InternalNode node3 = fifoLinkedList.addFirst(h3);
        final FifoLinkedList.InternalNode node4 = fifoLinkedList.addFirst(h4);

        Assertions.assertEquals(0, fifoLinkedList.getIndex(node4));
        Assertions.assertEquals(1, fifoLinkedList.getIndex(node3));
        Assertions.assertEquals(2, fifoLinkedList.getIndex(node2));
        Assertions.assertEquals(3, fifoLinkedList.getIndex(node1));

        Assertions.assertEquals(4, fifoLinkedList.size());
        Assertions.assertSame(h4, fifoLinkedList.get(0));
        Assertions.assertSame(h3, fifoLinkedList.get(1));
        Assertions.assertSame(h2, fifoLinkedList.get(2));
        Assertions.assertSame(h1, fifoLinkedList.get(3));

        fifoLinkedList.removeLast();

        Assertions.assertEquals(0, fifoLinkedList.getIndex(node4));
        Assertions.assertEquals(1, fifoLinkedList.getIndex(node3));
        Assertions.assertEquals(2, fifoLinkedList.getIndex(node2));
        Assertions.assertEquals(-1, fifoLinkedList.getIndex(node1));

        Assertions.assertEquals(3, fifoLinkedList.size());
        Assertions.assertSame(h4, fifoLinkedList.get(0));
        Assertions.assertSame(h3, fifoLinkedList.get(1));
        Assertions.assertSame(h2, fifoLinkedList.get(2));

        fifoLinkedList.removeLast();

        Assertions.assertEquals(0, fifoLinkedList.getIndex(node4));
        Assertions.assertEquals(1, fifoLinkedList.getIndex(node3));
        Assertions.assertEquals(-1, fifoLinkedList.getIndex(node2));
        Assertions.assertEquals(-1, fifoLinkedList.getIndex(node1));

        Assertions.assertEquals(2, fifoLinkedList.size());
        Assertions.assertSame(h4, fifoLinkedList.get(0));
        Assertions.assertSame(h3, fifoLinkedList.get(1));

        fifoLinkedList.removeLast();

        Assertions.assertEquals(0, fifoLinkedList.getIndex(node4));
        Assertions.assertEquals(-1, fifoLinkedList.getIndex(node3));
        Assertions.assertEquals(-1, fifoLinkedList.getIndex(node2));
        Assertions.assertEquals(-1, fifoLinkedList.getIndex(node1));

        Assertions.assertEquals(1, fifoLinkedList.size());
        Assertions.assertSame(h4, fifoLinkedList.get(0));

        fifoLinkedList.removeLast();

        Assertions.assertEquals(-1, fifoLinkedList.getIndex(node4));
        Assertions.assertEquals(-1, fifoLinkedList.getIndex(node3));
        Assertions.assertEquals(-1, fifoLinkedList.getIndex(node2));
        Assertions.assertEquals(-1, fifoLinkedList.getIndex(node1));

        Assertions.assertEquals(0, fifoLinkedList.size());
    }
}