add test for JdbcRDD using embedded derby, per rxin suggestion

.gitignore

@@ -36,3 +36,4 @@ streaming-tests.log
 dependency-reduced-pom.xml
 .ensime
 .ensime_lucene
+derby.log

core/src/test/scala/spark/rdd/JdbcRDDSuite.scala

+package spark
+
+import org.scalatest.{ BeforeAndAfter, FunSuite }
+import spark.SparkContext._
+import spark.rdd.JdbcRDD
+import java.sql._
+
+class JdbcRDDSuite extends FunSuite with BeforeAndAfter with LocalSparkContext {
+
+  before {
+    Class.forName("org.apache.derby.jdbc.EmbeddedDriver")
+    val conn = DriverManager.getConnection("jdbc:derby:target/JdbcRDDSuiteDb;create=true")
+    try {
+      val create = conn.createStatement
+      create.execute("""
+        CREATE TABLE FOO(
+          ID INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1),
+          DATA INTEGER
+        )""")
+      create.close
+      val insert = conn.prepareStatement("INSERT INTO FOO(DATA) VALUES(?)")
+      (1 to 100).foreach { i =>
+        insert.setInt(1, i * 2)
+        insert.executeUpdate
+      }
+      insert.close
+    } catch {
+      case e: SQLException if e.getSQLState == "X0Y32" =>
+        // table exists
+    } finally {
+      conn.close
+    }
+  }
+
+  test("basic functionality") {
+    sc = new SparkContext("local", "test")
+    val rdd = new JdbcRDD(
+      sc,
+      () => { DriverManager.getConnection("jdbc:derby:target/JdbcRDDSuiteDb") },
+      "SELECT DATA FROM FOO WHERE ? <= ID AND ID <= ?",
+      1, 100, 3,
+      (r: ResultSet) => { r.getInt(1) } ).cache
+
+    assert(rdd.count === 100)
+    assert(rdd.reduce(_+_) === 10100)
+  }
+
+  after {
+    try {
+      DriverManager.getConnection("jdbc:derby:;shutdown=true")
+    } catch {
+      case se: SQLException if se.getSQLState == "XJ015" =>
+        // normal shutdown
+    }
+  }
+}

project/SparkBuild.scala

@@ -147,6 +147,7 @@ object SparkBuild extends Build {
       "cc.spray" % "spray-can" % "1.0-M2.1",
       "cc.spray" % "spray-server" % "1.0-M2.1",
       "cc.spray" % "spray-json_2.9.2" % "1.1.1",
+      "org.apache.derby" % "derby" % "10.4.2.0" % "test",
       "org.apache.mesos" % "mesos" % "0.9.0-incubating"
     ) ++ (if (HADOOP_MAJOR_VERSION == "2") Some("org.apache.hadoop" % "hadoop-client" % HADOOP_VERSION) else None).toSeq,
     unmanagedSourceDirectories in Compile <+= baseDirectory{ _ / ("src/hadoop" + HADOOP_MAJOR_VERSION + "/scala") }