Author: joehni
Date: Wed Sep 6 00:16:04 2006
New Revision: 440640
URL: http://svn.apache.org/viewvc?view=rev&rev=440640
Log:
More robust tests on time-shifting machines.
Modified:
jakarta/commons/sandbox/id/trunk/src/test/org/apache/commons/id/serial/TimeBasedAlphanumericIdentifierGeneratorTest.java
Modified:
jakarta/commons/sandbox/id/trunk/src/test/org/apache/commons/id/serial/TimeBasedAlphanumericIdentifierGeneratorTest.java
URL:
http://svn.apache.org/viewvc/jakarta/commons/sandbox/id/trunk/src/test/org/apache/commons/id/serial/TimeBasedAlphanumericIdentifierGeneratorTest.java?view=diff&rev=440640&r1=440639&r2=440640
==============================================================================
---
jakarta/commons/sandbox/id/trunk/src/test/org/apache/commons/id/serial/TimeBasedAlphanumericIdentifierGeneratorTest.java
(original)
+++
jakarta/commons/sandbox/id/trunk/src/test/org/apache/commons/id/serial/TimeBasedAlphanumericIdentifierGeneratorTest.java
Wed Sep 6 00:16:04 2006
@@ -98,24 +98,23 @@
/**
* Test that the generator can be tweaked to start with '0'.
+ * @throws InterruptedException unexpected
*/
- public void testMayStartWithIdentifierOfZeros() {
+ public void testMayStartWithIdentifierOfZeros() throws
InterruptedException {
final int maxSize = Long.toString(Long.MAX_VALUE, 36).length();
final char[] zeros = new char[maxSize];
Arrays.fill(zeros, '0');
- // synchronize with current time slice ...
- final long waitForNextPeriod = System.currentTimeMillis();
- long next = waitForNextPeriod;
- while (next <= waitForNextPeriod) {
- next = System.currentTimeMillis();
- }
-
- // ... next id should be in same time slice if it is used as current
offset
- final StringIdentifierGenerator idGenerator = new
TimeBasedAlphanumericIdentifierGenerator(
- 0, next);
-
- assertEquals(new String(zeros), idGenerator.nextStringIdentifier());
+ final TimeSliceSynchronizer synchronizer = new TimeSliceSynchronizer()
{
+ void runTest() {
+ // ... next id should be in same time slice if it is used as
current offset
+ final StringIdentifierGenerator idGenerator = new
TimeBasedAlphanumericIdentifierGenerator(0, next);
+ // note, that this might still fail on time shifting machines
occasionally
+ assertEquals(new String(zeros),
idGenerator.nextStringIdentifier());
+ }
+
+ };
+ synchronizer.runSynced();
}
/**
@@ -171,39 +170,47 @@
/**
* Test ensures, that generator can recalculate the time from the id if
internally no overflow
* had happened.
+ * @throws InterruptedException unexpected
*/
- public void testCanRetrieveTimeFromIdWithoutInternalOverflow() {
- // synchronize with current time slice ...
- final long waitForNextPeriod = System.currentTimeMillis();
- final TimeBasedAlphanumericIdentifierGenerator idGenerator = new
TimeBasedAlphanumericIdentifierGenerator(
- 4, waitForNextPeriod - 1000);
-
- long next = waitForNextPeriod;
- while (next <= waitForNextPeriod) {
- next = System.currentTimeMillis();
- }
+ public void testCanRetrieveTimeFromIdWithoutInternalOverflow() throws
InterruptedException {
+ final TimeSliceSynchronizer synchronizer = new TimeSliceSynchronizer()
{
+ TimeBasedAlphanumericIdentifierGenerator idGenerator;
+ void initialize() {
+ idGenerator = new TimeBasedAlphanumericIdentifierGenerator(
+ 4, waitForNextPeriod - 1000);
+ }
- final String id = idGenerator.nextStringIdentifier();
- assertEquals(next, idGenerator.getMillisecondsFromId(id,
waitForNextPeriod - 1000));
+ void runTest() {
+ // note, that this might still fail on time shifting machines
occasionally
+ final String id = idGenerator.nextStringIdentifier();
+ assertEquals(next, idGenerator.getMillisecondsFromId(id,
waitForNextPeriod - 1000));
+ }
+
+ };
+ synchronizer.runSynced();
}
/**
* Test ensures, that generator can recalculate the time from the id even
if internally an
* overflow had happened.
+ * @throws InterruptedException unexpected
*/
- public void testCanRetrieveTimeFromIdWithInternalOverflow() {
- // synchronize with current time slice ...
- final long waitForNextPeriod = System.currentTimeMillis();
- final TimeBasedAlphanumericIdentifierGenerator idGenerator = new
TimeBasedAlphanumericIdentifierGenerator(
- 4, waitForNextPeriod + 1000);
-
- long next = waitForNextPeriod;
- while (next <= waitForNextPeriod) {
- next = System.currentTimeMillis();
- }
+ public void testCanRetrieveTimeFromIdWithInternalOverflow() throws
InterruptedException {
+ final TimeSliceSynchronizer synchronizer = new TimeSliceSynchronizer()
{
+ TimeBasedAlphanumericIdentifierGenerator idGenerator;
+ void initialize() {
+ idGenerator = new TimeBasedAlphanumericIdentifierGenerator(
+ 4, waitForNextPeriod + 1000);
+ }
- final String id = idGenerator.nextStringIdentifier();
- assertEquals(next, idGenerator.getMillisecondsFromId(id,
waitForNextPeriod + 1000));
+ void runTest() {
+ // note, that this might still fail on time shifting machines
occasionally
+ final String id = idGenerator.nextStringIdentifier();
+ assertEquals(next, idGenerator.getMillisecondsFromId(id,
waitForNextPeriod + 1000));
+ }
+
+ };
+ synchronizer.runSynced();
}
/**
@@ -252,5 +259,48 @@
}
}));
return suite;
+ }
+
+ /**
+ * A guardian class that tries hard to synchronize the test to run in the
same time slice of the CPU even on time
+ * shifting machines.
+ */
+ abstract static class TimeSliceSynchronizer {
+
+ long waitForNextPeriod;
+ long next;
+
+ void runSynced() throws InterruptedException {
+ // idea here is to generate an id in the same time slice of the
CPU as the last System.currentTimeMillis() call
+ int tries = 0;
+ for (;;) {
+ waitForNextPeriod = System.currentTimeMillis();
+ initialize();
+
+ next = waitForNextPeriod;
+ while (next == waitForNextPeriod) {
+ next = System.currentTimeMillis();
+ }
+
+ // sanity check, neither condition should normally occur, but
on time shifting machines we start over
+ if (next < waitForNextPeriod || next - waitForNextPeriod >
100) {
+ // we already tried 10 times to find a situation without
time shifting
+ if (++tries > 10) {
+ fail("Cannot perform this test on a machine, that is
steadily time shifting!");
+ }
+ Thread.sleep(1);
+ continue;
+ }
+
+ runTest();
+ break;
+ }
+ }
+
+ void initialize() {
+ // do nothing
+ }
+
+ abstract void runTest();
}
}
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