test: migrate histogram extension tests to JUnit 5 by FrankChen021 · Pull Request #19879 · apache/druid

FrankChen021 · 2026-08-04T15:06:06Z

Description

Migrates the extensions-core/histogram test suite from JUnit 4 to JUnit 5.

This is Batch 5 of the extensions-core migration and is part of #13948.

Depends on the earlier migration batches in #19875, #19876, #19877, and #19878.

The shared AggregationTestHelper now also accepts a JUnit 5 @TempDir directory while retaining the existing JUnit 4-compatible API for remaining migration batches.

Tests

mvn -ntp test -pl extensions-core/histogram -am \
  -Dtest='org.apache.druid.query.aggregation.histogram.**' \
  -Dsurefire.failIfNoSpecifiedTests=false \
  -Pskip-static-checks -Dweb.console.skip=true -T1C

Result: 211 tests passed; 0 failures, errors, or skips.

FrankChen021

I have reviewed the code for correctness, edge cases, concurrency, and integration risks; no issues found.

Reviewed 26 of 26 changed files.

This is an automated review by Codex GPT-5.6-Sol

FrankChen021

I have reviewed the updated code for correctness, edge cases, concurrency, and integration risks; no issues found.

Reviewed 26 of 26 changed files. The shared temporary-folder helper update preserves both legacy and Jupiter callers.

This is an automated review by Codex GPT-5.6-Sol

Copilot

Pull request overview

This PR continues the extensions-core JUnit 4 → JUnit 5 migration by converting the extensions-core/histogram test suite to Jupiter, while updating the shared AggregationTestHelper (in processing test fixtures) to support JUnit 5 @TempDir-style temp directories in addition to the existing JUnit 4 TemporaryFolder API.

Changes:

Update AggregationTestHelper to abstract temp-directory creation behind a provider and add JUnit 5-friendly WithTempDir factory methods.
Migrate histogram extension tests from JUnit 4 annotations/rules/assertions to JUnit 5 (Jupiter) equivalents, including parameterized test conversions.
Remove the JUnit Vintage engine dependency from the histogram module.

Reviewed changes

Copilot reviewed 26 out of 26 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
processing/src/test/java/org/apache/druid/query/aggregation/AggregationTestHelper.java	Introduces a temp-folder provider abstraction and adds JUnit 5 `@TempDir`-compatible helper factory methods.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/QuantilesTest.java	Switches to Jupiter assertions and updates Hamcrest usage.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/QuantilesPostAggregatorTest.java	Migrates assertions and expected-exception rule to Jupiter `assertThrows`.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/QuantilePostAggregatorTest.java	Migrates to Jupiter assertions.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/MinPostAggregatorTest.java	Migrates to Jupiter assertions.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/MaxPostAggregatorTest.java	Migrates to Jupiter assertions.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/FixedBucketsHistogramVectorAggregatorTest.java	Migrates lifecycle annotations to Jupiter and replaces JUnit 4 asserts.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/FixedBucketsHistogramTopNQueryTest.java	Converts from JUnit4 Parameterized runner to Jupiter parameterized tests.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/FixedBucketsHistogramTest.java	Migrates to Jupiter assertions.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/FixedBucketsHistogramGroupByQueryTest.java	Converts from JUnit4 Parameterized runner and expected-exception style to Jupiter parameterized tests + `assertThrows`.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/FixedBucketsHistogramBufferAggregatorTest.java	Migrates to Jupiter assertions and modernizes assertion message placement.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/FixedBucketsHistogramAggregationTest.java	Moves temp-dir handling from `TemporaryFolder` rule to Jupiter `@TempDir` with updated helper factory.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/EqualBucketsPostAggregatorTest.java	Migrates to Jupiter assertions.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/CustomBucketsPostAggregatorTest.java	Migrates to Jupiter assertions.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/BucketsPostAggregatorTest.java	Migrates to Jupiter assertions.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/ArrayUtilsTest.java	Migrates to Jupiter assertions.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/ApproximateHistogramVectorAggregatorTest.java	Migrates lifecycle annotations to Jupiter and replaces JUnit 4 asserts.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/ApproximateHistogramTopNQueryTest.java	Converts from JUnit4 Parameterized runner to Jupiter parameterized tests.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/ApproximateHistogramTest.java	Migrates to Jupiter assertions and converts `@Ignore` to `@Disabled`.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/ApproximateHistogramPostAggregatorTest.java	Migrates to Jupiter assertions.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/ApproximateHistogramGroupByQueryTest.java	Converts from JUnit4 Parameterized runner and expected-exception style to Jupiter parameterized tests + `assertThrows`.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/ApproximateHistogramFoldingVectorAggregatorTest.java	Migrates lifecycle annotations to Jupiter and replaces JUnit 4 asserts.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/ApproximateHistogramFoldingSerdeTest.java	Migrates to Jupiter assertions and updates assertion message placement.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/ApproximateHistogramAggregatorTest.java	Migrates to Jupiter assertions and updates assertion message placement.
extensions-core/histogram/src/test/java/org/apache/druid/query/aggregation/histogram/ApproximateHistogramAggregationTest.java	Moves temp-dir handling from `TemporaryFolder` rule to Jupiter `@TempDir` with updated helper factory.
extensions-core/histogram/pom.xml	Removes the JUnit Vintage engine dependency for the module.

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FrankChen021 · 2026-08-05T03:07:29Z

+  private QueryRunner runner;

-  public FixedBucketsHistogramTopNQueryTest(
+  public void initFixedBucketsHistogramTopNQueryTest(
      QueryRunner runner
  )


Thanks for flagging this. This was actionable and is already addressed by commit 1eb26ec9d8: the redundant runner field and initFixedBucketsHistogramTopNQueryTest method were removed, and the parameterized test uses its runner argument directly. The four affected histogram test classes passed (80 tests, 0 failures), with Checkstyle and SpotBugs reporting 0 violations/errors.

FrankChen021 · 2026-08-05T03:07:33Z

+  private QueryRunner runner;

-  public ApproximateHistogramTopNQueryTest(
+  public void initApproximateHistogramTopNQueryTest(
      QueryRunner runner
  )


Thanks for flagging this. This was actionable and is already addressed by commit 1eb26ec9d8: the redundant runner field and initApproximateHistogramTopNQueryTest method were removed, and the parameterized test uses its runner argument directly. The four affected histogram test classes passed (80 tests, 0 failures), with Checkstyle and SpotBugs reporting 0 violations/errors.

FrankChen021 · 2026-08-05T03:07:36Z

+  private QueryRunner<ResultRow> runner;
+  private GroupByQueryRunnerFactory factory;



Thanks for flagging this. This was actionable and is already addressed by commit 1eb26ec9d8: the unused instance factory/runner fields and initFixedBucketsHistogramGroupByQueryTest method were removed. The parameterized method still receives the feeder values and uses the runner argument; SerDe registration is now performed directly in each test body. The four affected histogram test classes passed (80 tests, 0 failures), with Checkstyle and SpotBugs reporting 0 violations/errors.

FrankChen021 · 2026-08-05T03:07:40Z

+  private QueryRunner<ResultRow> runner;
+  private GroupByQueryRunnerFactory factory;



Thanks for flagging this. This was actionable and is already addressed by commit 1eb26ec9d8: the unused instance factory/runner fields and initApproximateHistogramGroupByQueryTest method were removed. The parameterized method still receives the feeder values and uses the runner argument; SerDe registration is now performed directly in each test body. The four affected histogram test classes passed (80 tests, 0 failures), with Checkstyle and SpotBugs reporting 0 violations/errors.

+  @MethodSource("constructorFeeder")
+  @ParameterizedTest(name = "{0}")
+  public void testGroupByWithApproximateHistogramAgg(
+      String testName,


+  @MethodSource("constructorFeeder")
+  @ParameterizedTest(name = "{0}")
+  public void testGroupByWithSameNameComplexPostAgg(
+      String testName,


+  @MethodSource("constructorFeeder")
+  @ParameterizedTest(name = "{0}")
+  public void testGroupByWithFixedHistogramAgg(
+      String testName,


+  @MethodSource("constructorFeeder")
+  @ParameterizedTest(name = "{0}")
+  public void testGroupByWithSameNameComplexPostAgg(
+      String testName,


FrankChen021

I have reviewed the updated code for correctness, edge cases, concurrency, and integration risks; no issues found.

Reviewed 26 of 26 changed files. The incremental cleanup preserves method-source argument shapes and test setup, with test-annotation counts unchanged.

This is an automated review by Codex GPT-5.6-Sol

test: migrate histogram extension tests to JUnit 5

73206e6

This was referenced Aug 4, 2026

test: migrate s3 extension tests to JUnit 5 #19880

Merged

test: migrate datasketches extension tests to JUnit 5 #19881

Merged

FrankChen021 added 2 commits August 4, 2026 23:32

fix: use approved filesystem test utilities

d9955fc

style: format migrated tests

1564c07

github-actions Bot added the Area - Dependencies label Aug 4, 2026

FrankChen021 commented Aug 4, 2026

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test: preserve lazy aggregation temp folder creation

0c903dc

FrankChen021 commented Aug 4, 2026

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FrankChen021 marked this pull request as ready for review August 5, 2026 01:54

Copilot AI lite review requested due to automatic review settings August 5, 2026 01:54

Copilot started reviewing on behalf of FrankChen021 August 5, 2026 01:54 View session

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test: remove redundant histogram test state

1eb26ec

github-advanced-security AI found potential problems Aug 5, 2026

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fix: remove unused histogram test parameters

4872988

github-advanced-security AI found potential problems Aug 5, 2026

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FrankChen021 commented Aug 5, 2026

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GWphua approved these changes Aug 6, 2026

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FrankChen021 merged commit fb98ec5 into apache:master Aug 6, 2026
28 checks passed

FrankChen021 deleted the codex/junit5-migration-ext-core-5 branch August 6, 2026 12:44

github-actions Bot added this to the 39.0.0 milestone Aug 6, 2026

This was referenced Aug 6, 2026

test: migrate nine extensions-contrib modules to JUnit 5 #19908

Open

test: migrate server tests to JUnit 5 #19911

Draft

test: migrate second extensions-contrib batch to JUnit 5 #19915

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test: migrate third extensions-contrib batch to JUnit 5 #19916

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test: migrate histogram extension tests to JUnit 5 - #19879

test: migrate histogram extension tests to JUnit 5#19879
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		private QueryRunner<ResultRow> runner;
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