[SPARK-28996][SQL][TESTS] Add tests regarding username of HiveClient

sql/hive/src/main/scala/org/apache/spark/sql/hive/client/HiveClient.scala

@@ -292,4 +292,6 @@ private[hive] trait HiveClient {
   /** Used for testing only.  Removes all metadata from this instance of Hive. */
   def reset(): Unit
 
+  /** Returns the user name which is used as owner for Hive table. */
+  def userName: String
 }

sql/hive/src/main/scala/org/apache/spark/sql/hive/client/HiveClientImpl.scala

@@ -222,7 +222,7 @@ private[hive] class HiveClientImpl(
     hiveConf
   }
 
-  private val userName = UserGroupInformation.getCurrentUser.getShortUserName
+  override val userName = UserGroupInformation.getCurrentUser.getShortUserName
 
   override def getConf(key: String, defaultValue: String): String = {
     conf.get(key, defaultValue)

sql/hive/src/test/scala/org/apache/spark/sql/hive/client/HiveClientUserNameSuite.scala

@@ -0,0 +1,63 @@
+/*
+ * 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.spark.sql.hive.client
+
+import java.security.PrivilegedExceptionAction
+
+import org.apache.hadoop.conf.Configuration
+import org.apache.hadoop.security.UserGroupInformation
+import org.scalatest.{BeforeAndAfterAll, PrivateMethodTester}
+
+import org.apache.spark.util.Utils
+
+class HiveClientUserNameSuite(version: String) extends HiveVersionSuite(version) {
+
+  test("username of HiveClient - no UGI") {
+    // Assuming we're not faking System username
+    assert(getUserNameFromHiveClient === System.getProperty("user.name"))
+  }
+
+  test("username of HiveClient - UGI") {
+    val ugi = UserGroupInformation.createUserForTesting(
+      "[email protected]", Array.empty)
+    ugi.doAs(new PrivilegedExceptionAction[Unit]() {
+      override def run(): Unit = {
+        assert(getUserNameFromHiveClient === ugi.getShortUserName)
+      }
+    })
+  }
+
+  test("username of HiveClient - Proxy user") {
+    val ugi = UserGroupInformation.createUserForTesting(
+      "[email protected]", Array.empty)
+    val proxyUgi = UserGroupInformation.createProxyUserForTesting(
+      "[email protected]", ugi, Array.empty)
+    proxyUgi.doAs(new PrivilegedExceptionAction[Unit]() {
+      override def run(): Unit = {
+        assert(getUserNameFromHiveClient === proxyUgi.getShortUserName)
+      }
+    })
+  }
+
+  private def getUserNameFromHiveClient: String = {
+    val hadoopConf = new Configuration()
+    hadoopConf.set("hive.metastore.warehouse.dir", Utils.createTempDir().toURI().toString())
+    val client = buildClient(hadoopConf)
+    client.userName
+  }
+}

sql/hive/src/test/scala/org/apache/spark/sql/hive/client/HiveClientUserNameSuites.scala

@@ -0,0 +1,28 @@
+/*
+ * 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.spark.sql.hive.client
+
+import scala.collection.immutable.IndexedSeq
+
+import org.scalatest.Suite
+
+class HiveClientUserNameSuites extends Suite with HiveClientVersions {
+  override def nestedSuites: IndexedSeq[Suite] = {
+    versions.map(new HiveClientUserNameSuite(_))
+  }
+}

sql/hive/src/test/scala/org/apache/spark/sql/hive/client/HiveClientSuite.scala → sql/hive/src/test/scala/org/apache/spark/sql/hive/client/HivePartitionFilteringSuite.scala

@@ -31,8 +31,7 @@ import org.apache.spark.sql.catalyst.expressions._
 import org.apache.spark.sql.types.{BooleanType, IntegerType, LongType, StructType}
 import org.apache.spark.util.Utils
 
-// TODO: Refactor this to `HivePartitionFilteringSuite`
-class HiveClientSuite(version: String)
+class HivePartitionFilteringSuite(version: String)
     extends HiveVersionSuite(version) with BeforeAndAfterAll {
 
   private val tryDirectSqlKey = HiveConf.ConfVars.METASTORE_TRY_DIRECT_SQL.varname

sql/hive/src/test/scala/org/apache/spark/sql/hive/client/HiveClientSuites.scala → sql/hive/src/test/scala/org/apache/spark/sql/hive/client/HivePartitionFilteringSuites.scala

@@ -21,9 +21,9 @@ import scala.collection.immutable.IndexedSeq
 
 import org.scalatest.Suite
 
-class HiveClientSuites extends Suite with HiveClientVersions {
+class HivePartitionFilteringSuites extends Suite with HiveClientVersions {
   override def nestedSuites: IndexedSeq[Suite] = {
     // Hive 0.12 does not provide the partition filtering API we call
-    versions.filterNot(_ == "0.12").map(new HiveClientSuite(_))
+    versions.filterNot(_ == "0.12").map(new HivePartitionFilteringSuite(_))
   }
 }