/[cvs]/jsr166/src/test/tck/SystemTest.java
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Contents of /jsr166/src/test/tck/SystemTest.java

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Revision 1.8 - (show annotations)
Mon Nov 16 04:57:10 2009 UTC (9 years, 9 months ago) by jsr166
Branch: MAIN
Changes since 1.7: +2 -2 lines
whitespace

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 * Worst case rounding for millisecs; set for 60 cycle millis clock.
22 * This value might need to be changed os JVMs with coarser
23 * System.currentTimeMillis clocks.
24 */
25 static final long MILLIS_ROUND = 17;
26
27 /**
28 * Nanos between readings of millis is no longer than millis (plus
29 * possible rounding).
30 * This shows only that nano timing not (much) worse than milli.
31 */
32 public void testNanoTime1() {
33 try {
34 long m1 = System.currentTimeMillis();
35 Thread.sleep(1);
36 long n1 = System.nanoTime();
37 Thread.sleep(SHORT_DELAY_MS);
38 long n2 = System.nanoTime();
39 Thread.sleep(1);
40 long m2 = System.currentTimeMillis();
41 long millis = m2 - m1;
42 long nanos = n2 - n1;
43 assertTrue(nanos >= 0);
44 long nanosAsMillis = nanos / 1000000;
45 assertTrue(nanosAsMillis <= millis + MILLIS_ROUND);
46 }
47 catch (InterruptedException ie) {
48 unexpectedException();
49 }
50 }
51
52 /**
53 * Millis between readings of nanos is less than nanos, adjusting
54 * for rounding.
55 * This shows only that nano timing not (much) worse than milli.
56 */
57 public void testNanoTime2() {
58 try {
59 long n1 = System.nanoTime();
60 Thread.sleep(1);
61 long m1 = System.currentTimeMillis();
62 Thread.sleep(SHORT_DELAY_MS);
63 long m2 = System.currentTimeMillis();
64 Thread.sleep(1);
65 long n2 = System.nanoTime();
66 long millis = m2 - m1;
67 long nanos = n2 - n1;
68
69 assertTrue(nanos >= 0);
70 long nanosAsMillis = nanos / 1000000;
71 assertTrue(millis <= nanosAsMillis + MILLIS_ROUND);
72 }
73 catch (InterruptedException ie) {
74 unexpectedException();
75 }
76 }
77
78 }

dl@cs.oswego.edu
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