Execute correct delete operation in delta tests

This change use the correct table row deletion operation in the deleteRows method, which previosly
performed merge-with-delete operation instead of a true delete. Since most test tables do not have
delete vectors enabled, this change does not break existing tests.
To validate the change, a new test has been added with deletion vector property set for the test
table. However, the actual XTable conversion test is not part of this change, as it requires more
changes in the DeltaSource to correctly handle the deletion files. This will be addressed in future
update.

xtable-core/src/test/java/org/apache/xtable/TestSparkDeltaTable.java

@@ -134,7 +134,15 @@ public void upsertRows(List<Row> upsertRows) {
   }
 
   @SneakyThrows
+  @Override
   public void deleteRows(List<Row> deleteRows) {
+    String idsToDelete =
+        deleteRows.stream().map(row -> row.get(0).toString()).collect(Collectors.joining(", "));
+    deltaTable.delete("id in (" + idsToDelete + ")");
+  }
+
+  @SneakyThrows
+  public void mergeDeleteRows(List<Row> deleteRows) {
     List<Row> deletes = testDeltaHelper.transformForUpsertsOrDeletes(deleteRows, false);
     Dataset<Row> deleteDataset =
         sparkSession.createDataFrame(deletes, testDeltaHelper.getTableStructSchema());

xtable-core/src/test/java/org/apache/xtable/delta/ITDeltaDeleteVectorConvert.java

@@ -0,0 +1,155 @@
+/*
+ * 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.xtable.delta;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.spark.serializer.KryoSerializer;
+import org.apache.spark.sql.Row;
+import org.apache.spark.sql.SparkSession;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import org.apache.xtable.GenericTable;
+import org.apache.xtable.TestSparkDeltaTable;
+import org.apache.xtable.model.TableChange;
+
+public class ITDeltaDeleteVectorConvert {
+  @TempDir private static Path tempDir;
+  private static SparkSession sparkSession;
+
+  private DeltaConversionSourceProvider conversionSourceProvider;
+
+  @BeforeAll
+  public static void setupOnce() {
+    sparkSession =
+        SparkSession.builder()
+            .appName("TestDeltaTable")
+            .master("local[4]")
+            .config("spark.sql.extensions", "io.delta.sql.DeltaSparkSessionExtension")
+            .config(
+                "spark.sql.catalog.spark_catalog",
+                "org.apache.spark.sql.delta.catalog.DeltaCatalog")
+            .config("spark.databricks.delta.retentionDurationCheck.enabled", "false")
+            .config("spark.databricks.delta.schema.autoMerge.enabled", "true")
+            .config("spark.sql.shuffle.partitions", "1")
+            .config("spark.default.parallelism", "1")
+            .config("spark.serializer", KryoSerializer.class.getName())
+            .getOrCreate();
+  }
+
+  @AfterAll
+  public static void teardown() {
+    if (sparkSession != null) {
+      sparkSession.close();
+    }
+  }
+
+  @BeforeEach
+  void setUp() {
+    Configuration hadoopConf = new Configuration();
+    hadoopConf.set("fs.defaultFS", "file:///");
+
+    conversionSourceProvider = new DeltaConversionSourceProvider();
+    conversionSourceProvider.init(hadoopConf);
+  }
+
+  @Test
+  public void testInsertsUpsertsAndDeletes() {
+    String tableName = GenericTable.getTableName();
+    TestSparkDeltaTable testSparkDeltaTable =
+        new TestSparkDeltaTable(tableName, tempDir, sparkSession, null, false);
+
+    List<List<String>> allActiveFiles = new ArrayList<>();
+    List<TableChange> allTableChanges = new ArrayList<>();
+    List<Row> rows = testSparkDeltaTable.insertRows(50);
+    Long timestamp1 = testSparkDeltaTable.getLastCommitTimestamp();
+    allActiveFiles.add(testSparkDeltaTable.getAllActiveFiles());
+
+    // enable deletion vectors for the test table
+    testSparkDeltaTable
+        .getSparkSession()
+        .sql(
+            "ALTER TABLE "
+                + tableName
+                + " SET TBLPROPERTIES ('delta.enableDeletionVectors' = true)");
+
+    List<Row> rows1 = testSparkDeltaTable.insertRows(50);
+    allActiveFiles.add(testSparkDeltaTable.getAllActiveFiles());
+    assertEquals(100L, testSparkDeltaTable.getNumRows());
+
+    // upsert does not create delete vectors
+    testSparkDeltaTable.upsertRows(rows.subList(0, 20));
+    allActiveFiles.add(testSparkDeltaTable.getAllActiveFiles());
+    assertEquals(100L, testSparkDeltaTable.getNumRows());
+
+    testSparkDeltaTable.insertRows(50);
+    allActiveFiles.add(testSparkDeltaTable.getAllActiveFiles());
+    assertEquals(150L, testSparkDeltaTable.getNumRows());
+
+    // delete a few rows with gaps in ids
+    List<Row> rowsToDelete =
+        rows1.subList(0, 10).stream()
+            .filter(row -> (row.get(0).hashCode() % 2) == 0)
+            .collect(Collectors.toList());
+    rowsToDelete.addAll(rows.subList(35, 45));
+    testSparkDeltaTable.deleteRows(rowsToDelete);
+    allActiveFiles.add(testSparkDeltaTable.getAllActiveFiles());
+    assertEquals(135L, testSparkDeltaTable.getNumRows());
+
+    testSparkDeltaTable.insertRows(50);
+    allActiveFiles.add(testSparkDeltaTable.getAllActiveFiles());
+    assertEquals(185L, testSparkDeltaTable.getNumRows());
+
+    // delete a few rows from a file which already has a deletion vector, this should generate a
+    // merged deletion vector file. Some rows were already deleted in the previous delete step.
+    // This deletion step intentionally deletes the same rows again to test the merge.
+    rowsToDelete = rows1.subList(5, 15);
+    testSparkDeltaTable.deleteRows(rowsToDelete);
+    allActiveFiles.add(testSparkDeltaTable.getAllActiveFiles());
+    assertEquals(178L, testSparkDeltaTable.getNumRows());
+
+    testSparkDeltaTable.insertRows(50);
+    allActiveFiles.add(testSparkDeltaTable.getAllActiveFiles());
+    assertEquals(228L, testSparkDeltaTable.getNumRows());
+
+    // TODO conversion fails if delete vectors are enabled, this is because of missing handlers for
+    // deletion files.
+    // TODO pending for another PR
+    //    SourceTable tableConfig =
+    //        SourceTable.builder()
+    //            .name(testSparkDeltaTable.getTableName())
+    //            .basePath(testSparkDeltaTable.getBasePath())
+    //            .formatName(TableFormat.DELTA)
+    //            .build();
+    //    DeltaConversionSource conversionSource =
+    //        conversionSourceProvider.getConversionSourceInstance(tableConfig);
+    //    InternalSnapshot internalSnapshot = conversionSource.getCurrentSnapshot();
+    //
+  }
+}