set server state to UNKNOWN if ReadHealthStep fails to obtain server state from WebLogic

Author: alai8

operator/src/main/java/oracle/kubernetes/operator/steps/ReadHealthStep.java

@@ -20,6 +20,7 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import oracle.kubernetes.operator.Pair;
 import oracle.kubernetes.operator.ProcessingConstants;
+import oracle.kubernetes.operator.WebLogicConstants;
 import oracle.kubernetes.operator.helpers.DomainPresenceInfo;
 import oracle.kubernetes.operator.http.HttpClient;
 import oracle.kubernetes.operator.http.Result;
@@ -192,7 +193,7 @@ private Pair<String, ServerHealth> createServerHealthFromResult(Result restResul
         return parseServerHealthJson(restResult.getResponse());
       }
       return new Pair<>(
-          "",
+          WebLogicConstants.UNKNOWN_STATE,
           new ServerHealth()
               .withOverallHealth(
                   restResult.isServerOverloaded()

operator/src/test/java/oracle/kubernetes/operator/steps/ReadHealthStepTest.java

@@ -10,7 +10,6 @@
 import static oracle.kubernetes.operator.logging.MessageKeys.WLS_HEALTH_READ_FAILED_NO_HTTPCLIENT;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.is;
-import static org.hamcrest.Matchers.nullValue;
 
 import com.meterware.simplestub.Memento;
 import com.meterware.simplestub.Stub;
@@ -189,7 +188,7 @@ public void withHttpClientStep_verifyServerHealthForServerOverloadedAddedToPacke
     assertThat(
         serverHealth.getOverallHealth(), is(ReadHealthStep.OVERALL_HEALTH_FOR_SERVER_OVERLOADED));
     Map<String, String> serverStateMap = packet.getValue(SERVER_STATE_MAP);
-    assertThat(serverStateMap.get(MANAGED_SERVER1), nullValue());
+    assertThat(serverStateMap.get(MANAGED_SERVER1), is("UNKNOWN"));
   }
 
   @Test
@@ -205,7 +204,7 @@ public void withHttpClientStep_verifyServerHealthForOtherErrorAddedToPacket() {
     ServerHealth serverHealth = serverHealthMap.get(MANAGED_SERVER1);
     assertThat(serverHealth.getOverallHealth(), is(ReadHealthStep.OVERALL_HEALTH_NOT_AVAILABLE));
     Map<String, String> serverStateMap = packet.getValue(SERVER_STATE_MAP);
-    assertThat(serverStateMap.get(MANAGED_SERVER1), nullValue());
+    assertThat(serverStateMap.get(MANAGED_SERVER1), is("UNKNOWN"));
   }
 
   static final String OK_RESPONSE =