[SPARK] Add more testing for variant + delta features (delta-io#3102)

<!--
Thanks for sending a pull request!  Here are some tips for you:
1. If this is your first time, please read our contributor guidelines:
https://github.com/delta-io/delta/blob/master/CONTRIBUTING.md
2. If the PR is unfinished, add '[WIP]' in your PR title, e.g., '[WIP]
Your PR title ...'.
  3. Be sure to keep the PR description updated to reflect all changes.
  4. Please write your PR title to summarize what this PR proposes.
5. If possible, provide a concise example to reproduce the issue for a
faster review.
6. If applicable, include the corresponding issue number in the PR title
and link it in the body.
-->

#### Which Delta project/connector is this regarding?
<!--
Please add the component selected below to the beginning of the pull
request title
For example: [Spark] Title of my pull request
-->

- [x] Spark
- [ ] Standalone
- [ ] Flink
- [ ] Kernel
- [ ] Other (fill in here)

## Description

<!--
- Describe what this PR changes.
- Describe why we need the change.
 
If this PR resolves an issue be sure to include "Resolves #XXX" to
correctly link and close the issue upon merge.
-->

adds testing for auto compaction and deletion vectors

## How was this patch tested?

test only change

## Does this PR introduce _any_ user-facing changes?

<!--
If yes, please clarify the previous behavior and the change this PR
proposes - provide the console output, description and/or an example to
show the behavior difference if possible.
If possible, please also clarify if this is a user-facing change
compared to the released Delta Lake versions or within the unreleased
branches such as master.
If no, write 'No'.
-->

spark/src/test/scala/org/apache/spark/sql/delta/AutoCompactSuite.scala

@@ -21,6 +21,7 @@ import java.io.File
 
 // scalastyle:off import.ordering.noEmptyLine
 import com.databricks.spark.util.{Log4jUsageLogger, UsageRecord}
+import org.apache.spark.sql.delta.DeltaExcludedBySparkVersionTestMixinShims
 import org.apache.spark.sql.delta.actions.AddFile
 import org.apache.spark.sql.delta.commands.optimize._
 import org.apache.spark.sql.delta.hooks.{AutoCompact, AutoCompactType}
@@ -32,7 +33,7 @@ import org.apache.spark.sql.delta.test.DeltaTestImplicits._
 import org.apache.spark.sql.delta.util.JsonUtils
 import org.apache.hadoop.fs.Path
 
-import org.apache.spark.sql.Column
+import org.apache.spark.sql.{Column, DataFrame}
 import org.apache.spark.sql.catalyst.TableIdentifier
 import org.apache.spark.sql.catalyst.expressions.Literal
 import org.apache.spark.sql.test.SharedSparkSession
@@ -60,7 +61,8 @@ class AutoCompactSuite extends
     CompactionTestHelperForAutoCompaction
   with DeltaSQLCommandTest
   with SharedSparkSession
-  with AutoCompactTestUtils {
+  with AutoCompactTestUtils
+  with DeltaExcludedBySparkVersionTestMixinShims {
 
   test("auto-compact-type: test table properties") {
     withTempDir { tempDir =>
@@ -184,15 +186,20 @@ class AutoCompactSuite extends
     }
   }
 
-  private def checkAutoCompactionWorks(dir: String): Unit = {
-    spark.range(10).write.format("delta").mode("append").save(dir)
+  /**
+   * Writes `df` twice to the same location and checks that
+   *   1. There is only one resultant file.
+   *   2. The result is equal to `df` unioned with itself.
+   */
+  private def checkAutoCompactionWorks(dir: String, df: DataFrame): Unit = {
+    df.write.format("delta").mode("append").save(dir)
     val deltaLog = DeltaLog.forTable(spark, dir)
     val newSnapshot = deltaLog.update()
     assert(newSnapshot.version === 1) // 0 is the first commit, 1 is optimize
     assert(deltaLog.update().numOfFiles === 1)
 
     val isLogged = checkAutoOptimizeLogging {
-      spark.range(10).write.format("delta").mode("append").save(dir)
+      df.write.format("delta").mode("append").save(dir)
     }
 
     assert(isLogged)
@@ -202,17 +209,40 @@ class AutoCompactSuite extends
 
     assert(deltaLog.update().numOfFiles === 1, "Files should be optimized into a single one")
     checkAnswer(
-      spark.range(10).union(spark.range(10)).toDF(),
+      df.union(df).toDF(),
       spark.read.format("delta").load(dir)
     )
   }
 
   testBothModesViaProperty("auto compact should kick in when enabled - table config") { dir =>
-    checkAutoCompactionWorks(dir)
+    checkAutoCompactionWorks(dir, spark.range(10).toDF("id"))
   }
 
   testBothModesViaConf("auto compact should kick in when enabled - session config") { dir =>
-    checkAutoCompactionWorks(dir)
+    checkAutoCompactionWorks(dir, spark.range(10).toDF("id"))
+  }
+
+  testSparkMasterOnly("variant auto compact kicks in when enabled - table config") {
+    withTempDir { dir =>
+      withSQLConf(
+          "spark.databricks.delta.properties.defaults.autoOptimize.autoCompact" -> "true",
+          DeltaSQLConf.DELTA_AUTO_COMPACT_MIN_NUM_FILES.key -> "0",
+          DeltaSQLConf.DELTA_AUTO_COMPACT_MODIFIED_PARTITIONS_ONLY_ENABLED.key -> "false") {
+        checkAutoCompactionWorks(
+          dir.getCanonicalPath, spark.range(10).selectExpr("parse_json(cast(id as string)) as v"))
+      }
+    }
+  }
+
+  testSparkMasterOnly("variant auto compact kicks in when enabled - session config") {
+    withTempDir { dir =>
+      withSQLConf(
+          DeltaSQLConf.DELTA_AUTO_COMPACT_ENABLED.key -> "true",
+          DeltaSQLConf.DELTA_AUTO_COMPACT_MIN_NUM_FILES.key -> "0") {
+        checkAutoCompactionWorks(
+          dir.getCanonicalPath, spark.range(10).selectExpr("parse_json(cast(id as string)) as v"))
+      }
+    }
   }
 
   testBothModesViaProperty("auto compact should not kick in when session config is off") { dir =>

spark/src/test/scala/org/apache/spark/sql/delta/deletionvectors/DeletionVectorsSuite.scala

@@ -19,7 +19,7 @@ package org.apache.spark.sql.delta.deletionvectors
 import java.io.{File, FileNotFoundException}
 import java.net.URISyntaxException
 
-import org.apache.spark.sql.delta.{DeletionVectorsTableFeature, DeletionVectorsTestUtils, DeltaChecksumException, DeltaConfigs, DeltaLog, DeltaMetricsUtils, DeltaTestUtilsForTempViews}
+import org.apache.spark.sql.delta.{DeletionVectorsTableFeature, DeletionVectorsTestUtils, DeltaChecksumException, DeltaConfigs, DeltaExcludedBySparkVersionTestMixinShims, DeltaLog, DeltaMetricsUtils, DeltaTestUtilsForTempViews}
 import org.apache.spark.sql.delta.DeltaTestUtils.createTestAddFile
 import org.apache.spark.sql.delta.actions.{AddFile, DeletionVectorDescriptor, RemoveFile}
 import org.apache.spark.sql.delta.actions.DeletionVectorDescriptor.EMPTY
@@ -46,7 +46,8 @@ class DeletionVectorsSuite extends QueryTest
   with DeltaSQLCommandTest
   with DeletionVectorsTestUtils
   with DeltaTestUtilsForTempViews
-  with DeltaExceptionTestUtils {
+  with DeltaExceptionTestUtils
+  with DeltaExcludedBySparkVersionTestMixinShims {
   import testImplicits._
 
   override def beforeAll(): Unit = {
@@ -270,7 +271,7 @@ class DeletionVectorsSuite extends QueryTest
     }
   }
 
-  Seq("name", "id").foreach(mode =>
+  Seq("name", "id").foreach { mode =>
     test(s"DELETE with DVs with column mapping mode=$mode") {
       withSQLConf("spark.databricks.delta.properties.defaults.columnMapping.mode" -> mode) {
         withTempDir { dirName =>
@@ -286,7 +287,26 @@ class DeletionVectorsSuite extends QueryTest
         }
       }
     }
-  )
+
+    testSparkMasterOnly(s"variant types DELETE with DVs with column mapping mode=$mode") {
+      withSQLConf("spark.databricks.delta.properties.defaults.columnMapping.mode" -> mode) {
+        withTempDir { dirName =>
+          val path = dirName.getAbsolutePath
+          val df = spark.range(0, 50).selectExpr(
+            "id % 10 as part",
+            "id",
+            "parse_json(cast(id as string)) as v"
+          )
+          df.write.format("delta").partitionBy("part").save(path)
+          val tableLog = DeltaLog.forTable(spark, path)
+          enableDeletionVectorsInTable(tableLog, true)
+          spark.sql(s"DELETE FROM delta.`$path` WHERE v::int = 2")
+          checkAnswer(spark.sql(s"select * from delta.`$path` WHERE v::int = 2"), Seq())
+          verifyDVsExist(tableLog, 1)
+        }
+      }
+    }
+  }
 
   test("DELETE with DVs - existing table already has DVs") {
     withSQLConf(DeltaSQLConf.DELETE_USE_PERSISTENT_DELETION_VECTORS.key -> "true") {