Parse results of minikube status more rigorously (apache#97)

* Parse results of minikube status more rigorously

Prior code assumes the minikubeVM status line is always the first row output
from minikube status, and it is not when the version upgrade notifier prints
an upgrade suggestion message.

* Also filter ip response to expected rows

resource-managers/kubernetes/integration-tests/src/test/scala/org/apache/spark/deploy/kubernetes/integrationtest/minikube/Minikube.scala

@@ -19,6 +19,7 @@ package org.apache.spark.deploy.kubernetes.integrationtest.minikube
 import java.io.{BufferedReader, InputStreamReader}
 import java.nio.file.Paths
 import java.util.concurrent.TimeUnit
+import java.util.regex.Pattern
 import javax.net.ssl.X509TrustManager
 
 import io.fabric8.kubernetes.client.{ConfigBuilder, DefaultKubernetesClient}
@@ -58,13 +59,17 @@ private[spark] object Minikube extends Logging {
   def getMinikubeIp: String = synchronized {
     assert(MINIKUBE_EXECUTABLE_DEST.exists(), EXPECTED_DOWNLOADED_MINIKUBE_MESSAGE)
     val outputs = executeMinikube("ip")
+      .filter(_.matches("^\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}$"))
     assert(outputs.size == 1, "Unexpected amount of output from minikube ip")
     outputs.head
   }
 
   def getMinikubeStatus: MinikubeStatus.Value = synchronized {
     assert(MINIKUBE_EXECUTABLE_DEST.exists(), EXPECTED_DOWNLOADED_MINIKUBE_MESSAGE)
-    val statusString = executeMinikube("status").head.replaceFirst("minikubeVM: ", "")
+    val statusString = executeMinikube("status")
+      .filter(_.contains("minikubeVM: "))
+      .head
+      .replaceFirst("minikubeVM: ", "")
     MinikubeStatus.unapply(statusString)
         .getOrElse(throw new IllegalStateException(s"Unknown status $statusString"))
   }