antlr-3.4/tool/src/test/java/org/antlr/test/TestFastQueue.java

/*
 * [The "BSD license"]
 *  Copyright (c) 2010 Terence Parr
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 *      derived from this software without specific prior written permission.
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package org.antlr.test;

import org.antlr.runtime.misc.FastQueue;
import org.junit.Test;

import java.util.NoSuchElementException;

import static org.junit.Assert.assertEquals;

public class TestFastQueue {
    @Test public void testQueueNoRemove() throws Exception {
        FastQueue<String> q = new FastQueue<String>();
        q.add("a");
        q.add("b");
        q.add("c");
        q.add("d");
        q.add("e");
        String expecting = "a b c d e";
        String found = q.toString();
        assertEquals(expecting, found);
    }

    @Test public void testQueueThenRemoveAll() throws Exception {
        FastQueue<String> q = new FastQueue<String>();
        q.add("a");
        q.add("b");
        q.add("c");
        q.add("d");
        q.add("e");
        StringBuffer buf = new StringBuffer();
        while ( q.size()>0 ) {
            String o = q.remove();
            buf.append(o);
            if ( q.size()>0 ) buf.append(" ");
        }
        assertEquals("queue should be empty", 0, q.size());
        String expecting = "a b c d e";
        String found = buf.toString();
        assertEquals(expecting, found);
    }

    @Test public void testQueueThenRemoveOneByOne() throws Exception {
        StringBuffer buf = new StringBuffer();
        FastQueue<String> q = new FastQueue<String>();
        q.add("a");
        buf.append(q.remove());
        q.add("b");
        buf.append(q.remove());
        q.add("c");
        buf.append(q.remove());
        q.add("d");
        buf.append(q.remove());
        q.add("e");
        buf.append(q.remove());
        assertEquals("queue should be empty", 0, q.size());
        String expecting = "abcde";
        String found = buf.toString();
        assertEquals(expecting, found);
    }

    // E r r o r s

    @Test public void testGetFromEmptyQueue() throws Exception {
        FastQueue<String> q = new FastQueue<String>();
        String msg = null;
        try { q.remove(); }
        catch (NoSuchElementException nsee) {
            msg = nsee.getMessage();
        }
        String expecting = "queue index 0 > last index -1";
        String found = msg;
        assertEquals(expecting, found);
    }

    @Test public void testGetFromEmptyQueueAfterSomeAdds() throws Exception {
        FastQueue<String> q = new FastQueue<String>();
        q.add("a");
        q.add("b");
        q.remove();
        q.remove();
        String msg = null;
        try { q.remove(); }
        catch (NoSuchElementException nsee) {
            msg = nsee.getMessage();
        }
        String expecting = "queue index 0 > last index -1";
        String found = msg;
        assertEquals(expecting, found);
    }

    @Test public void testGetFromEmptyQueueAfterClear() throws Exception {
        FastQueue<String> q = new FastQueue<String>();
        q.add("a");
        q.add("b");
        q.clear();
        String msg = null;
        try { q.remove(); }
        catch (NoSuchElementException nsee) {
            msg = nsee.getMessage();
        }
        String expecting = "queue index 0 > last index -1";
        String found = msg;
        assertEquals(expecting, found);
    }
}