fix: address datasketches migration review comments

Author: FrankChen021

extensions-core/datasketches/src/test/java/org/apache/druid/query/aggregation/datasketches/hll/HllSketchMergeAggregatorFactoryTest.java

@@ -130,8 +130,7 @@ public void testGetMergingFactoryDifferentStringEncoding()
           SHOULD_FINALIZE,
           ROUND
       );
-      HllSketchAggregatorFactory result = (HllSketchAggregatorFactory) targetRound.getMergingFactory(other);
-      Assertions.assertEquals(LG_K, result.getLgK());
+      targetRound.getMergingFactory(other);
     });
   }
 

extensions-core/datasketches/src/test/java/org/apache/druid/query/aggregation/datasketches/theta/SketchAggregationWithSimpleDataTest.java

@@ -34,7 +34,6 @@
 import org.apache.druid.java.util.common.granularity.Granularities;
 import org.apache.druid.java.util.common.guava.Sequence;
 import org.apache.druid.query.Druids;
-import org.apache.druid.query.QueryContexts;
 import org.apache.druid.query.Result;
 import org.apache.druid.query.aggregation.AggregationTestHelper;
 import org.apache.druid.query.aggregation.post.FieldAccessPostAggregator;
@@ -53,7 +52,6 @@
 import org.apache.druid.query.topn.TopNResultValue;
 import org.apache.druid.testing.InitializedNullHandlingTest;
 import org.junit.jupiter.api.Assertions;
-import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.io.TempDir;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
@@ -71,19 +69,10 @@ public class SketchAggregationWithSimpleDataTest extends InitializedNullHandling
   @TempDir
   private File tempFolder;
 
-  private GroupByQueryConfig config;
-  private QueryContexts.Vectorize vectorize;
-
   private SketchModule sm;
   private File s1;
   private File s2;
 
-  public void initSketchAggregationWithSimpleDataTest(GroupByQueryConfig config, String vectorize)
-  {
-    this.config = config;
-    this.vectorize = QueryContexts.Vectorize.fromString(vectorize);
-  }
-
   public static Collection<?> constructorFeeder()
   {
     final List<Object[]> constructors = new ArrayList<>();
@@ -95,8 +84,7 @@ public static Collection<?> constructorFeeder()
     return constructors;
   }
 
-  @BeforeEach
-  public void setup() throws Exception
+  private void setup(final GroupByQueryConfig config) throws Exception
   {
     SketchModule.registerSerde();
     sm = new SketchModule();
@@ -150,7 +138,7 @@ public void setup() throws Exception
   @ParameterizedTest(name = "config = {0}, vectorize = {1}")
   public void testSimpleDataIngestAndGpByQuery(GroupByQueryConfig config, String vectorize) throws Exception
   {
-    initSketchAggregationWithSimpleDataTest(config, vectorize);
+    setup(config);
     try (
         final AggregationTestHelper gpByQueryAggregationTestHelper = AggregationTestHelper.createGroupByQueryAggregationTestHelperWithTempDir(
             sm.getJacksonModules(),
@@ -309,7 +297,7 @@ public void testSimpleDataIngestAndGpByQuery(GroupByQueryConfig config, String v
   @ParameterizedTest(name = "config = {0}, vectorize = {1}")
   public void testSimpleDataIngestAndTimeseriesQuery(GroupByQueryConfig config, String vectorize) throws Exception
   {
-    initSketchAggregationWithSimpleDataTest(config, vectorize);
+    setup(config);
     AggregationTestHelper timeseriesQueryAggregationTestHelper = AggregationTestHelper.createTimeseriesQueryAggregationTestHelperWithTempDir(
         sm.getJacksonModules(),
         tempFolder
@@ -392,7 +380,7 @@ public void testSimpleDataIngestAndTimeseriesQuery(GroupByQueryConfig config, St
   @ParameterizedTest(name = "config = {0}, vectorize = {1}")
   public void testSimpleDataIngestAndTopNQuery(GroupByQueryConfig config, String vectorize) throws Exception
   {
-    initSketchAggregationWithSimpleDataTest(config, vectorize);
+    setup(config);
     AggregationTestHelper topNQueryAggregationTestHelper = AggregationTestHelper.createTopNQueryAggregationTestHelperWithTempDir(
         sm.getJacksonModules(),
         tempFolder
@@ -479,7 +467,7 @@ public void testSimpleDataIngestAndTopNQuery(GroupByQueryConfig config, String v
   @ParameterizedTest(name = "config = {0}, vectorize = {1}")
   public void testTopNQueryWithSketchConstant(GroupByQueryConfig config, String vectorize) throws Exception
   {
-    initSketchAggregationWithSimpleDataTest(config, vectorize);
+    setup(config);
     AggregationTestHelper topNQueryAggregationTestHelper = AggregationTestHelper.createTopNQueryAggregationTestHelperWithTempDir(
         sm.getJacksonModules(),
         tempFolder

extensions-core/datasketches/src/test/java/org/apache/druid/query/aggregation/datasketches/theta/oldapi/OldApiSketchAggregationTest.java

@@ -91,7 +91,10 @@ public static Collection<?> constructorFeeder()
   @AfterEach
   public void teardown() throws IOException
   {
-    helper.close();
+    if (helper != null) {
+      helper.close();
+      helper = null;
+    }
   }
 
   @MethodSource("constructorFeeder")