test/tck/SystemTest.java

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/licenses/publicdomain
 * Other contributors include Andrew Wright, Jeffrey Hayes, 
 * Pat Fisher, Mike Judd. 
 */

import junit.framework.*;

public class SystemTest extends JSR166TestCase {
    public static void main(String[] args) {
        junit.textui.TestRunner.run(suite());   
    }
    
    public static Test suite() {
        return new TestSuite(SystemTest.class);
    }

    /**
     * Nanos between readings of millis is no longer than millis (plus
     * one milli to allow for rounding).
     * This shows only that nano timing not (much) worse than milli.
     */
    public void testNanoTime1() {
        try {
            long m1 = System.currentTimeMillis();
            Thread.sleep(1);
            long n1 = System.nanoTime();
            Thread.sleep(SHORT_DELAY_MS);
            long n2 = System.nanoTime();
            Thread.sleep(1);
            long m2 = System.currentTimeMillis();
            long millis = m2 - m1;
            long nanos = n2 - n1;
            
            assertTrue(nanos >= 0);
            assertTrue(nanos < (millis+1) * 1000000);
        }
        catch(InterruptedException ie) {
            unexpectedException();
        }
    }

    /**
     * Millis between readings of nanos is no longer than nanos
     * This shows only that nano timing not (much) worse than milli.
     */
    public void testNanoTime2() {
        try {
            long n1 = System.nanoTime();
            Thread.sleep(1);
            long m1 = System.currentTimeMillis();
            Thread.sleep(SHORT_DELAY_MS);
            long m2 = System.currentTimeMillis();
            Thread.sleep(1);
            long n2 = System.nanoTime();
            long millis = m2 - m1;
            long nanos = n2 - n1;
            
            assertTrue(nanos >= 0);
            assertTrue(millis * 1000000 <= nanos);
        }
        catch(InterruptedException ie) {
            unexpectedException();
        }
    }

}

Revision:	1.5
Committed:	Sat Dec 27 19:26:44 2003 UTC (20 years, 4 months ago) by dl
Branch:	MAIN
Changes since 1.4:	+5 -4 lines
Log Message:	Headers reference Creative Commons
#	Content
1	/*
2	* Written by Doug Lea with assistance from members of JCP JSR-166
3	* Expert Group and released to the public domain, as explained at
4	* http://creativecommons.org/licenses/publicdomain
5	* Other contributors include Andrew Wright, Jeffrey Hayes,
6	* Pat Fisher, Mike Judd.
7	*/
8
9	import junit.framework.*;
10
11	public class SystemTest extends JSR166TestCase {
12	public static void main(String[] args) {
13	junit.textui.TestRunner.run(suite());
14	}
15
16	public static Test suite() {
17	return new TestSuite(SystemTest.class);
18	}
19
20	/**
21	* Nanos between readings of millis is no longer than millis (plus
22	* one milli to allow for rounding).
23	* This shows only that nano timing not (much) worse than milli.
24	*/
25	public void testNanoTime1() {
26	try {
27	long m1 = System.currentTimeMillis();
28	Thread.sleep(1);
29	long n1 = System.nanoTime();
30	Thread.sleep(SHORT_DELAY_MS);
31	long n2 = System.nanoTime();
32	Thread.sleep(1);
33	long m2 = System.currentTimeMillis();
34	long millis = m2 - m1;
35	long nanos = n2 - n1;
36
37	assertTrue(nanos >= 0);
38	assertTrue(nanos < (millis+1) * 1000000);
39	}
40	catch(InterruptedException ie) {
41	unexpectedException();
42	}
43	}
44
45	/**
46	* Millis between readings of nanos is no longer than nanos
47	* This shows only that nano timing not (much) worse than milli.
48	*/
49	public void testNanoTime2() {
50	try {
51	long n1 = System.nanoTime();
52	Thread.sleep(1);
53	long m1 = System.currentTimeMillis();
54	Thread.sleep(SHORT_DELAY_MS);
55	long m2 = System.currentTimeMillis();
56	Thread.sleep(1);
57	long n2 = System.nanoTime();
58	long millis = m2 - m1;
59	long nanos = n2 - n1;
60
61	assertTrue(nanos >= 0);
62	assertTrue(millis * 1000000 <= nanos);
63	}
64	catch(InterruptedException ie) {
65	unexpectedException();
66	}
67	}
68
69	}
70