Merge pull request #1 from dongjoon-hyun/PR-22788

Refactor the test case

Author: huaxingao

sql/core/src/test/scala/org/apache/spark/sql/ColumnExpressionSuite.scala

@@ -25,6 +25,7 @@ import org.apache.hadoop.io.{LongWritable, Text}
 import org.apache.hadoop.mapreduce.lib.input.{TextInputFormat => NewTextInputFormat}
 import org.scalatest.Matchers._
 
+import org.apache.spark.sql.catalyst.analysis.UnresolvedAttribute
 import org.apache.spark.sql.catalyst.expressions.NamedExpression
 import org.apache.spark.sql.execution.ProjectExec
 import org.apache.spark.sql.functions._
@@ -114,6 +115,16 @@ class ColumnExpressionSuite extends QueryTest with SharedSQLContext {
       Row("a") :: Nil)
   }
 
+  test("SPARK-25769 escape nested columns by backtick each of the column name") {
+    Seq(
+      ($"a.b", "`a`.`b`"),
+      ($"`a.b`", "`a.b`"),
+      ($"`a`.b", "`a`.`b`"),
+      ($"`a.b`.c", "`a.b`.`c`")).foreach { case (columnName, sqlString) =>
+      assert(columnName.expr.sql === sqlString)
+    }
+  }
+
   test("alias and name") {
     val df = Seq((1, Seq(1, 2, 3))).toDF("a", "intList")
     assert(df.select(df("a").as("b")).columns.head === "b")

sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala

@@ -2856,21 +2856,6 @@ class SQLQuerySuite extends QueryTest with SharedSQLContext {
       checkAnswer(sql("select 26393499451 / (1e6 * 1000)"), Row(BigDecimal("26.3934994510000")))
     }
   }
-
-  test("SPARK-25769 escape nested columns") {
-    import org.apache.spark.sql.catalyst.analysis.UnresolvedAttribute
-    val sql1 = $"a.b".expr.asInstanceOf[UnresolvedAttribute].sql
-    assert(sql1 === "`a`.`b`")
-
-    val sql2 = $"`a.b`".expr.asInstanceOf[UnresolvedAttribute].sql
-    assert(sql2 === "`a.b`")
-
-    val sql3 = $"`a`.b".expr.asInstanceOf[UnresolvedAttribute].sql
-    assert(sql3 === "`a`.`b`")
-
-    val sql4 = $"`a.b`.c".expr.asInstanceOf[UnresolvedAttribute].sql
-    assert(sql4 === "`a.b`.`c`")
-  }
 }
 
 case class Foo(bar: Option[String])