JoshRosen commented on code in PR #49212: URL: https://github.com/apache/spark/pull/49212#discussion_r1907998126
########## core/src/test/scala/org/apache/spark/util/BestEffortLazyValSuite.scala: ########## @@ -0,0 +1,99 @@ +/* + * 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 + * + * http://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.spark.util + +import java.io.NotSerializableException + +import org.apache.spark.{SerializerHelper, SparkFunSuite} + +class BestEffortLazyValSuite extends SparkFunSuite with SerializerHelper { + + test("BestEffortLazy works") { + var test: Option[Object] = None + + val lazyval = new BestEffortLazyVal(() => { + test = Some(new Object()) + test + }) + + // Ensure no initialization happened before the lazy value was invoked + assert(test.isEmpty) + + // Ensure the first invocation creates a new object + assert(lazyval() == test && test.isDefined) + + // Ensure the subsequent invocation serves the same object + assert(lazyval() == test && test.isDefined) Review Comment: To be pedantic: If we want to assert that both invocations return the same object then we need to actually store the result across invocations and compare the stored results. Also: as the test is written now, I believe that this would still pass even if you were incorrectly re-initializing on every call. I'm being nit-picky about this because a test which passes even if the code implementation is wrong is misleading. Let me take a stab at writing my own suggested version of this test case, including a case which actually detects that the compare-and-swap works correctly (i.e. a test which passes when CAS is used and fails if the CAS is replaced with a blind write). -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
