Clean-up, add tests

sql/core/src/main/scala/org/apache/spark/sql/execution/debug/package.scala

@@ -134,6 +134,11 @@ package object debug {
     }
   }
 
+  /**
+   * :: DeveloperApi ::
+   * Helper functions for checking that runtime types match a given schema.
+   */
+  @DeveloperApi
   object TypeCheck {
     def typeCheck(data: Any, schema: DataType): Unit = (data, schema) match {
       case (null, _) =>
@@ -159,13 +164,20 @@ package object debug {
     }
   }
 
-  case class TypeCheck(child: SparkPlan) extends SparkPlan {
+  /**
+   * :: DeveloperApi ::
+   * Augments SchemaRDDs with debug methods.
+   */
+  @DeveloperApi
+  private[sql] case class TypeCheck(child: SparkPlan) extends SparkPlan {
     import TypeCheck._
-    //def otherCopyArgs = null :: Nil
 
     override def nodeName  = ""
 
-    override def makeCopy(args: Array[Object]): this.type = TypeCheck(args(0).asInstanceOf[SparkPlan]).asInstanceOf[this.type]
+    /* Only required when defining this class in a REPL.
+    override def makeCopy(args: Array[Object]): this.type =
+      TypeCheck(args(0).asInstanceOf[SparkPlan]).asInstanceOf[this.type]
+    */
 
     def output = child.output
 

sql/core/src/test/scala/org/apache/spark/sql/execution/debug/DebuggingSuite.scala

@@ -0,0 +1,33 @@
+/*
+ * 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.execution.debug
+
+import org.scalatest.FunSuite
+
+import org.apache.spark.sql.TestData._
+import org.apache.spark.sql.test.TestSQLContext._
+
+class DebuggingSuite extends FunSuite {
+  test("SchemaRDD.debug()") {
+    testData.debug()
+  }
+
+  test("SchemaRDD.typeCheck()") {
+    testData.typeCheck()
+  }
+}