HDDS-6401. Fix flaky TestFilePerBlockStrategy.testWriteAndReadChunkMultipleTimes

[kuenishi]

What changes were proposed in this pull request?

When ChunkUtils.writeData() finishes too fast, elapsed time for writing data in test case becomes zero because it's resolution is a bit rough, in milliseconds. That leads to the failure of test assertion that checks elapsed time being >0. Here, the check must be on written bytes and ops.

I think this failure does not affect any released version, but current master HEAD is deterministically failing in the unit test due to this issue.

2022-03-02 19:29:26,493 [main] INFO  volume.HddsVolume (HddsVolume.java:<init>(120)) - Creating HddsVolume: /tmp/junit871563182678035731/hdds of storage type : null capacity : 9223372036854775807
2022-03-02 19:29:27,280 [main] WARN  util.NativeCodeLoader (NativeCodeLoader.java:<clinit>(60)) - Unable to load native-hadoop library for your platform... using builtin-java classes where applicable

java.lang.AssertionError
	at org.junit.Assert.fail(Assert.java:87)
	at org.junit.Assert.assertTrue(Assert.java:42)
	at org.junit.Assert.assertTrue(Assert.java:53)
	at org.apache.hadoop.ozone.container.keyvalue.impl.CommonChunkManagerTestCases.testWriteAndReadChunkMultipleTimes(CommonChunkManagerTestCases.java:228)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
....

What is the link to the Apache JIRA

HDDS-6401

How was this patch tested?

This is a test code fix

[adoroszlai]

Thanks @kuenishi for the patch. I have never seen this specific assertion fail in CI. But based on experience with similar time-based tests I can imagine this might fail in some environments.

Removing the assertion is OK. But we can omit the new assertions, as bytes and count are already checked in checkWriteIOStats:

ozone/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/keyvalue/impl/AbstractTestChunkManager.java

Lines 137 to 141 in 53d25b9

	protected void checkWriteIOStats(long length, long opCount) {
	VolumeIOStats volumeIOStats = hddsVolume.getVolumeIOStats();
	assertEquals(length, volumeIOStats.getWriteBytes());
	assertEquals(opCount, volumeIOStats.getWriteOpCount());
	}

[kuenishi]

That makes sense, thank you. I committed your suggestion.