Using test UGI to mimic current user and groups

Change-Id: Iafc17472e44a511402a3faa5e1889fa445b3c386

Author: jerryshao

core/src/test/scala/org/apache/spark/deploy/SparkHadoopUtilSuite.scala

@@ -17,6 +17,10 @@
 
 package org.apache.spark.deploy
 
+import java.security.PrivilegedExceptionAction
+
+import scala.util.Random
+
 import org.apache.hadoop.fs.FileStatus
 import org.apache.hadoop.fs.permission.{FsAction, FsPermission}
 import org.apache.hadoop.security.UserGroupInformation
@@ -30,37 +34,55 @@ class SparkHadoopUtilSuite extends SparkFunSuite with Matchers {
     val user = UserGroupInformation.getCurrentUser.getShortUserName
     val groups = UserGroupInformation.getCurrentUser.getGroupNames
     require(!groups.isEmpty)
-    val sparkHadoopUtil = new SparkHadoopUtil
-
-    // If file is owned by user and user has access permission
-    var status = fileStatus(user, groups.head, READ_WRITE, READ_WRITE, NONE)
-    sparkHadoopUtil.checkAccessPermission(status, READ) should be (true)
-    sparkHadoopUtil.checkAccessPermission(status, WRITE) should be (true)
-
-    // If file is owned by user but user has no access permission
-    status = fileStatus(user, groups.head, NONE, READ_WRITE, NONE)
-    sparkHadoopUtil.checkAccessPermission(status, READ) should be (false)
-    sparkHadoopUtil.checkAccessPermission(status, WRITE) should be (false)
-
-    // If file is owned by user's group and user's group has access permission
-    status = fileStatus("test", groups.head, NONE, READ_WRITE, NONE)
-    sparkHadoopUtil.checkAccessPermission(status, READ) should be (true)
-    sparkHadoopUtil.checkAccessPermission(status, WRITE) should be (true)
-
-    // If file is owned by user's group but user's group has no access permission
-    status = fileStatus("test", groups.head, READ_WRITE, NONE, NONE)
-    sparkHadoopUtil.checkAccessPermission(status, READ) should be (false)
-    sparkHadoopUtil.checkAccessPermission(status, WRITE) should be (false)
-
-    // If file is owned by other user and this user has access permission
-    status = fileStatus("test", "test", READ_WRITE, READ_WRITE, READ_WRITE)
-    sparkHadoopUtil.checkAccessPermission(status, READ) should be (true)
-    sparkHadoopUtil.checkAccessPermission(status, WRITE) should be (true)
-
-    // If file is owned by other user but this user has no access permission
-    status = fileStatus("test", "test", READ_WRITE, READ_WRITE, NONE)
-    sparkHadoopUtil.checkAccessPermission(status, READ) should be (false)
-    sparkHadoopUtil.checkAccessPermission(status, WRITE) should be (false)
+
+    val testUser = user + "-" + Random.nextInt(100)
+    val testGroups = groups.map { g => g + "-" + Random.nextInt(100) }
+    val testUgi = UserGroupInformation.createUserForTesting(testUser, testGroups)
+
+    testUgi.doAs(new PrivilegedExceptionAction[Void] {
+      override def run(): Void = {
+        val sparkHadoopUtil = new SparkHadoopUtil
+
+        // If file is owned by user and user has access permission
+        var status = fileStatus(testUser, testGroups.head, READ_WRITE, READ_WRITE, NONE)
+        sparkHadoopUtil.checkAccessPermission(status, READ) should be(true)
+        sparkHadoopUtil.checkAccessPermission(status, WRITE) should be(true)
+
+        // If file is owned by user but user has no access permission
+        status = fileStatus(testUser, testGroups.head, NONE, READ_WRITE, NONE)
+        sparkHadoopUtil.checkAccessPermission(status, READ) should be(false)
+        sparkHadoopUtil.checkAccessPermission(status, WRITE) should be(false)
+
+        var otherUser = "test"
+        var otherGroup = "test"
+        while (otherUser == testUser || testGroups.contains(otherGroup)) {
+          otherUser = s"test-${Random.nextInt(100)}"
+          otherGroup = s"test-${Random.nextInt(100)}"
+        }
+
+        // If file is owned by user's group and user's group has access permission
+        status = fileStatus(otherUser, testGroups.head, NONE, READ_WRITE, NONE)
+        sparkHadoopUtil.checkAccessPermission(status, READ) should be(true)
+        sparkHadoopUtil.checkAccessPermission(status, WRITE) should be(true)
+
+        // If file is owned by user's group but user's group has no access permission
+        status = fileStatus(otherUser, testGroups.head, READ_WRITE, NONE, NONE)
+        sparkHadoopUtil.checkAccessPermission(status, READ) should be(false)
+        sparkHadoopUtil.checkAccessPermission(status, WRITE) should be(false)
+
+        // If file is owned by other user and this user has access permission
+        status = fileStatus(otherUser, otherGroup, READ_WRITE, READ_WRITE, READ_WRITE)
+        sparkHadoopUtil.checkAccessPermission(status, READ) should be(true)
+        sparkHadoopUtil.checkAccessPermission(status, WRITE) should be(true)
+
+        // If file is owned by other user but this user has no access permission
+        status = fileStatus(otherUser, otherGroup, READ_WRITE, READ_WRITE, NONE)
+        sparkHadoopUtil.checkAccessPermission(status, READ) should be(false)
+        sparkHadoopUtil.checkAccessPermission(status, WRITE) should be(false)
+
+        null
+      }
+    })
   }
 
   private def fileStatus(