Adding test for non-default persistence level

bagel/src/test/scala/bagel/BagelSuite.scala

@@ -7,6 +7,7 @@ import org.scalatest.time.SpanSugar._
 import scala.collection.mutable.ArrayBuffer
 
 import spark._
+import storage.StorageLevel
 
 class TestVertex(val active: Boolean, val age: Int) extends Vertex with Serializable
 class TestMessage(val targetId: String) extends Message[String] with Serializable
@@ -79,4 +80,21 @@ class BagelSuite extends FunSuite with Assertions with BeforeAndAfter with Timeo
       }
     }
   }
+
+  test("using non-default persistence level") {
+    failAfter(10 seconds) {
+      sc = new SparkContext("local", "test")
+      val verts = sc.parallelize((1 to 4).map(id => (id.toString, new TestVertex(true, 0))))
+      val msgs = sc.parallelize(Array[(String, TestMessage)]())
+      val numSupersteps = 50
+      val result =
+        Bagel.run(sc, verts, msgs, sc.defaultParallelism, StorageLevel.DISK_ONLY) {
+          (self: TestVertex, msgs: Option[Array[TestMessage]], superstep: Int) =>
+            (new TestVertex(superstep < numSupersteps - 1, self.age + 1), Array[TestMessage]())
+        }
+      for ((id, vert) <- result.collect) {
+        assert(vert.age === numSupersteps)
+      }
+    }
+  }
 }