yashdeep97 opened a new pull request, #15418: URL: https://github.com/apache/druid/pull/15418
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Remove this section if there is no corresponding issue. Don't reference the issue in the title of this pull-request. --> <!-- If you are a committer, follow the PR action item checklist for committers: https://github.com/apache/druid/blob/master/dev/committer-instructions.md#pr-and-issue-action-item-checklist-for-committers. --> ### Description <!-- Describe the goal of this PR, what problem are you fixing. If there is a corresponding issue (referenced above), it's not necessary to repeat the description here, however, you may choose to keep one summary sentence. --> <!-- Describe your patch: what did you change in code? How did you fix the problem? --> <!-- If there are several relatively logically separate changes in this PR, create a mini-section for each of them. For example: --> #### Fixed the following flaky tests: 1. org.apache.druid.segment.nested.NestedDataColumnSupplierV4Test#testBasicFunctionality 2. org.apache.druid.segment.nested.NestedDataColumnSupplierV4Test#testConcurrency 3. org.apache.druid.segment.nested.NestedDataColumnSupplierTest#testBasicFunctionality 4. org.apache.druid.segment.nested.NestedDataColumnSupplierTest#testArrayFunctionality 5. org.apache.druid.segment.nested.NestedDataColumnSupplierTest#testConcurrency 6. org.apache.druid.segment.virtual.ExpressionVirtualColumnTest#testRequiredColumns #### Problem: The above mentioned tests have been reported as flaky (tests assuming deterministic implementation of a non-deterministic specification ) when ran against the [NonDex](https://github.com/TestingResearchIllinois/NonDex) tool. The tests contain assertions that compare strings created from JSON objects([Assertion 1](https://github.com/apache/druid/blob/fb260f3e412522a4993d43209b2bc20cb3dae80c/processing/src/test/java/org/apache/druid/segment/nested/NestedDataColumnSupplierTest.java#L408) and lists created from HashSets & [Assertion 2](https://github.com/apache/druid/blob/fb260f3e412522a4993d43209b2bc20cb3dae80c/processing/src/test/java/org/apache/druid/segment/virtual/ExpressionVirtualColumnTest.java#L737)). However, HashSet does not guarantee the ordering of elements and thus resulting in these flaky tests that assume deterministic implementation of HashSet. Also, It checks for a specific ordering of elements in a JSON string. JSON strings are equal even if the ordering of the elements in the JSON strings are not equal. This results in flakiness as the Jackson ObjectMapper does not guarantee consistent ordering of the JSON keys. Thus, when the NonDex tool shuffles the HashSet elements and the JSON keys, it results in test failures like: ``` [ERROR] Failures: [ERROR] org.apache.druid.segment.nested.NestedDataColumnSupplierTest.testArrayFunctionality [ERROR] Run 1: NestedDataColumnSupplierTest.testArrayFunctionality:291->smokeTestArrays:644 expected:<{"[s":["b","c"],"l":[null,null],"d":[1.1,null,2.2]]}> but was:<{"[d":[1.1,null,2.2],"s":["b","c"],"l":[null,null]]}> [ERROR] Run 2: NestedDataColumnSupplierTest.testArrayFunctionality:291->smokeTestArrays:644 expected:<{"s":["a","b","c"],"[l":[1,2,3],"d":[1.1,2.2]]}> but was:<{"s":["a","b","c"],"[d":[1.1,2.2],"l":[1,2,3]]}> [ERROR] Run 3: NestedDataColumnSupplierTest.testArrayFunctionality:291->smokeTestArrays:644 expected:<{"[d":[1.1,2.2],"l":[1,2,3]],"s":["a","b","c"]}> but was:<{"[l":[1,2,3],"d":[1.1,2.2]],"s":["a","b","c"]}> [ERROR] Run 4: NestedDataColumnSupplierTest.testArrayFunctionality:291->smokeTestArrays:644 expected:<{"[l":[null,null],"d":[1.1,null,2.2],"s":["b","c"]]}> but was:<{"[s":["b","c"],"d":[1.1,null,2.2],"l":[null,null]]}> ----------------- [ERROR] org.apache.druid.segment.virtual.ExpressionVirtualColumnTest.testRequiredColumns [ERROR] Run 1: ExpressionVirtualColumnTest.testRequiredColumns:737 expected:<[x, y]> but was:<[y, x]> ``` To reproduce run: ``` mvn -pl processing edu.illinois:nondex-maven-plugin:2.1.1:nondex -Dtest=<test_name> ``` <!-- In each section, please describe design decisions made, including: - Choice of algorithms - Behavioral aspects. 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If something hasn't changed since the original discussion, you can omit a detailed discussion of those aspects of the design here, perhaps apart from brief mentioning for the sake of readability of this PR description. --> <!-- Some of the aspects mentioned above may be omitted for simple and small changes. --> <!-- Give your best effort to summarize your changes in a couple of sentences aimed toward Druid users. If your change doesn't have end user impact, you can skip this section. For tips about how to write a good release note, see [Release notes](https://github.com/apache/druid/blob/master/CONTRIBUTING.md#release-notes). --> #### Fix: For the test `org.apache.druid.segment.virtual.ExpressionVirtualColumnTest#testRequiredColumns`, first convert the arraylists to hashSets and then compare the 2 HashSets using assertEquals(). For all other tests in `NestedDataColumnSupplierTest` and `NestedDataColumnSupplierV4Test` classes, first create the JSON node trees and then compare the two trees using assertEquals(). ##### Key changed/added classes in this PR * `org.apache.druid.segment.nested.NestedDataColumnSupplierV4Test` * `org.apache.druid.segment.nested.NestedDataColumnSupplierTest` * `org.apache.druid.segment.virtual.ExpressionVirtualColumnTest` <hr> <!-- Check the items by putting "x" in the brackets for the done things. Not all of these items apply to every PR. Remove the items which are not done or not relevant to the PR. 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