keith-turner commented on code in PR #4494: URL: https://github.com/apache/accumulo/pull/4494#discussion_r1596742581
########## server/manager/src/test/java/org/apache/accumulo/manager/ManagerTimeTest.java: ########## @@ -0,0 +1,128 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * https://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ +package org.apache.accumulo.manager; + +import static org.junit.jupiter.api.Assertions.assertArrayEquals; +import static org.junit.jupiter.api.Assertions.assertEquals; +import static org.junit.jupiter.api.Assertions.assertTrue; + +import java.util.List; + +import org.apache.accumulo.core.util.time.SteadyTime; +import org.junit.jupiter.api.Test; +import org.junit.jupiter.params.ParameterizedTest; +import org.junit.jupiter.params.provider.ValueSource; + +public class ManagerTimeTest { + + @Test + public void testSteadyTime() { + long time = 20_000; + var steadyTime = SteadyTime.from(time); + + // make sure calling serialize on instance matches static helper + byte[] serialized = ManagerTime.serialize(steadyTime); + assertArrayEquals(serialized, ManagerTime.serialize(steadyTime)); + + // Verify deserialization matches original object + var deserialized = ManagerTime.deserialize(serialized); + assertEquals(steadyTime, deserialized); + assertEquals(0, steadyTime.compareTo(deserialized)); + } + + @ParameterizedTest + // Test with both a 0 and positive previous value. This simulates the value + // read out of zookeeper for the time and should never be negative as it is + // based on elapsed time from previous manager runs + @ValueSource(longs = {0, 50_000}) + public void testSteadyTimeFromSkew(long previousTime) throws InterruptedException { + List<Long> times = List.of(-100_000L, -100L, 0L, 20_000L, System.nanoTime()); + + for (Long time : times) { + // ManagerTime builds the skew amount by subtracting the current nanotime + // from the previous persisted time in ZK. The skew can be negative or positive because + // it will depend on if the current nanotime is negative or positive as + // nanotime is allowed to be negative + var skewAmount = ManagerTime.updateSkew(SteadyTime.from(previousTime), time); + + // Build a SteadyTime using the skewAmount + // SteadyTime should never be negative + var original = ManagerTime.fromSkew(time, skewAmount); + + // Simulate a future time and create another SteadyTime from the skew which should + // now be after the original + time = time + 10000; + var futureSkew = ManagerTime.fromSkew(time, skewAmount); + + // future should be after the original + assertTrue(futureSkew.compareTo(original) > 0); + } + } + + @ParameterizedTest + // Test with both a 0 and positive previous value. This simulates the value + // read out of zookeeper for the time and should never be negative as it is + // based on elapsed time from previous manager runs + @ValueSource(longs = {0, 50_000}) + public void testSteadyTimeFromSkewCurrent(long previousTime) throws InterruptedException { + // Also test fromSkew(skewAmount) method which only uses System.nanoTime() + var skewAmount = ManagerTime.updateSkew(SteadyTime.from(previousTime)); + + // Build a SteadyTime using the skewAmount and current time + var original = ManagerTime.fromSkew(skewAmount); Review Comment: @cshannon the explanation was really helpful. It would be really nice to add that example with the 4 steps to the ManagerTime javadoc, it makes it easy to understand what is going on with the skew. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: notifications-unsubscr...@accumulo.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
