fixes for SNAP-2307 (#1116)

compatibilityTests/src/test/scala/org/apache/spark/sql/SnappyTableScanSuite.scala

@@ -17,10 +17,89 @@
 package org.apache.spark.sql
 
 import org.apache.spark.sql.sources.TableScanSuite
-import org.apache.spark.sql.test.SharedSnappySessionContext
+import org.apache.spark.sql.test.{SharedSnappySessionContext, SnappySparkTestUtil}
 
-class SnappyTableScanSuite extends TableScanSuite with SharedSnappySessionContext{
-  // SimpleScanSource, an external source is not found while
-  // creating internal table. changing it to external
-  override val tableTypes = Seq("TEMPORARY VIEW", "EXTERNAL TABLE")
+class SnappyTableScanSuite
+  extends TableScanSuite
+    with SharedSnappySessionContext
+    with SnappySparkTestUtil {
+
+  // all tests in TableScanSuite will run except for below tests
+  // read comments above each test for desc on fixes
+  override def excluded: Seq[String] = Seq(
+    "exceptions",
+    "read the data source tables that do not extend SchemaRelationProvider",
+    "SPARK-5196 schema field with comment"
+  )
+
+  // SimpleScanSource is external to snappy. changed 'TABLE' to 'EXTERNAL TABLE'
+  test("SD:exceptions") {
+    // Make sure we do throw correct exception when users use a relation provider that
+    // only implements the RelationProvider or the SchemaRelationProvider.
+    Seq("TEMPORARY VIEW", "EXTERNAL TABLE").foreach { tableType =>
+      val schemaNotAllowed = intercept[Exception] {
+        sql(
+          s"""
+             |CREATE $tableType relationProvierWithSchema (i int)
+             |USING org.apache.spark.sql.sources.SimpleScanSource
+             |OPTIONS (
+             |  From '1',
+             |  To '10'
+             |)
+           """.stripMargin)
+      }
+      assert(schemaNotAllowed.getMessage.contains("does not allow user-specified schemas"))
+
+      val schemaNeeded = intercept[Exception] {
+        sql(
+          s"""
+             |CREATE $tableType schemaRelationProvierWithoutSchema
+             |USING org.apache.spark.sql.sources.AllDataTypesScanSource
+             |OPTIONS (
+             |  From '1',
+             |  To '10'
+             |)
+           """.stripMargin)
+      }
+      assert(schemaNeeded.getMessage.contains("A schema needs to be specified when using"))
+    }
+  }
+
+  // SimpleScanSource is external to snappy. changed 'TABLE' to 'EXTERNAL TABLE'
+  test("SD:read the data source tables that do not extend SchemaRelationProvider") {
+    Seq("TEMPORARY VIEW", "EXTERNAL TABLE").foreach { tableType =>
+      val tableName = "relationProvierWithSchema"
+      withTable(tableName) {
+        sql(
+          s"""
+             |CREATE $tableType $tableName
+             |USING org.apache.spark.sql.sources.SimpleScanSource
+             |OPTIONS (
+             |  From '1',
+             |  To '10'
+             |)
+           """.stripMargin)
+        checkAnswer(spark.table(tableName), spark.range(1, 11).toDF())
+      }
+    }
+  }
+
+  // according to snappy implementation comment desc needs ' not "
+  test("SD:SPARK-5196 schema field with comment") {
+    sql(
+      """
+        |CREATE TEMPORARY VIEW student(name string comment 'SN', age int comment 'SA', grade int)
+        |USING org.apache.spark.sql.sources.AllDataTypesScanSource
+        |OPTIONS (
+        |  from '1',
+        |  to '10',
+        |  option_with_underscores 'someval',
+        |  option.with.dots 'someval'
+        |)
+      """.stripMargin)
+
+    val planned = sql("SELECT * FROM student").queryExecution.executedPlan
+    val comments = planned.schema.fields.map(_.getComment().getOrElse("NO_COMMENT")).mkString(",")
+    assert(comments === "SN,SA,NO_COMMENT")
+  }
 }