Fix #283

Author: steveniemitz

src/scala/main/ly/stealth/mesos/kafka/json/Model.scala

@@ -243,9 +243,9 @@ class ClusterDeserializer extends StdDeserializer[Cluster](classOf[Cluster]) {
     val model = p.readValueAs(classOf[ClusterModel])
     val c = new Cluster()
     c.frameworkId = model.frameworkId
-    for (b <- model.brokers)
-      c.addBroker(b)
-
+    Option(model.brokers).toList
+      .flatten
+      .foreach(c.addBroker)
     c
   }
 }

src/test/ly/stealth/mesos/kafka/ClusterTest.scala

@@ -65,6 +65,14 @@ class ClusterTest extends KafkaMesosTestCase {
     assertEquals(2, read.getBrokers.size())
   }
 
+  @Test
+  def load_empty_cluster: Unit = {
+    val jsData = "{\"version\":\"0.10.1.0-SNAPSHOT\"}"
+    val cluster = JsonUtil.fromJson[Cluster](jsData)
+    assertNotNull(cluster.getBrokers)
+    assertEquals(0, cluster.getBrokers.size())
+  }
+
   @Test
   def toJson_fromJson {
     val broker0 = cluster.addBroker(new Broker("0"))