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/publicdomain/zero/1.0/
 * Other contributors include Andrew Wright, Jeffrey Hayes,
 * Pat Fisher, Mike Judd.
 */

import junit.framework.Test;
import junit.framework.TestSuite;

public class SystemTest extends JSR166TestCase {
    public static void main(String[] args) {
        main(suite(), args);
    }

    public static Test suite() {
        return new TestSuite(SystemTest.class);
    }

    /**
     * Worst case rounding for millisecs; set for 60 cycle millis clock.
     * This value might need to be changed on JVMs with coarser
     * System.currentTimeMillis clocks.
     */
    static final long MILLIS_ROUND = 17;

    /**
     * Nanos between readings of millis is no longer than millis (plus
     * possible rounding), and vice versa.
     * This shows only that nano timing not (much) worse than milli.
     */
    public void testNanoTime() throws InterruptedException {
        long m0 = System.currentTimeMillis();
        long n0 = System.nanoTime();
        Thread.sleep(1);
        long m1 = System.currentTimeMillis();
        long n1 = System.nanoTime();
        Thread.sleep(50);       // avoid possibly scaled SHORT_DELAY_MS
        long m2 = System.currentTimeMillis();
        long n2 = System.nanoTime();
        Thread.sleep(1);
        long m3 = System.currentTimeMillis();
        long n3 = System.nanoTime();
        assertTrue((n2 - n1) / 1_000_000 <= m3 - m0 + MILLIS_ROUND);
        assertTrue(m2 - m1 <= (n3 - n0) / 1_000_000 + MILLIS_ROUND);
    }
}
Revision:	1.14
Committed:	Sun May 14 03:09:25 2017 UTC (6 years, 11 months ago) by jsr166
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.13:	+11 -32 lines
Log Message:	coalesce low-value expensive tests
#	User	Rev	Content
1	dl	1.1	/*
2	dl	1.5	* 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	jsr166	1.11	* http://creativecommons.org/publicdomain/zero/1.0/
5	jsr166	1.7	* Other contributors include Andrew Wright, Jeffrey Hayes,
6			* Pat Fisher, Mike Judd.
7	dl	1.1	*/
8
9	jsr166	1.12	import junit.framework.Test;
10			import junit.framework.TestSuite;
11	dl	1.1
12	dl	1.2	public class SystemTest extends JSR166TestCase {
13	dl	1.1	public static void main(String[] args) {
14	jsr166	1.13	main(suite(), args);
15	dl	1.1	}
16	jsr166	1.7
17	dl	1.1	public static Test suite() {
18	tim	1.4	return new TestSuite(SystemTest.class);
19	dl	1.1	}
20
21	jsr166	1.7	/**
22	dl	1.6	* Worst case rounding for millisecs; set for 60 cycle millis clock.
23	jsr166	1.9	* This value might need to be changed on JVMs with coarser
24	jsr166	1.10	* System.currentTimeMillis clocks.
25	dl	1.6	*/
26			static final long MILLIS_ROUND = 17;
27
28	dl	1.2	/**
29	tim	1.4	* Nanos between readings of millis is no longer than millis (plus
30	jsr166	1.14	* possible rounding), and vice versa.
31	dl	1.2	* This shows only that nano timing not (much) worse than milli.
32			*/
33	jsr166	1.14	public void testNanoTime() throws InterruptedException {
34			long m0 = System.currentTimeMillis();
35			long n0 = System.nanoTime();
36			Thread.sleep(1);
37	jsr166	1.9	long m1 = System.currentTimeMillis();
38			long n1 = System.nanoTime();
39	jsr166	1.14	Thread.sleep(50); // avoid possibly scaled SHORT_DELAY_MS
40			long m2 = System.currentTimeMillis();
41	jsr166	1.9	long n2 = System.nanoTime();
42			Thread.sleep(1);
43	jsr166	1.14	long m3 = System.currentTimeMillis();
44			long n3 = System.nanoTime();
45			assertTrue((n2 - n1) / 1_000_000 <= m3 - m0 + MILLIS_ROUND);
46			assertTrue(m2 - m1 <= (n3 - n0) / 1_000_000 + MILLIS_ROUND);
47	dl	1.1	}
48			}