Fix tests

Author: msm1992

components/apimgt/org.wso2.carbon.apimgt.impl/src/main/java/org/wso2/carbon/apimgt/impl/factory/GatewayHolder.java

@@ -99,10 +99,14 @@ public static GatewayDeployer getTenantGatewayInstance(String organization, Stri
                 if (environment != null) {
                     GatewayAgentConfiguration gatewayAgentConfiguration = ServiceReferenceHolder.getInstance().
                             getExternalGatewayConnectorConfiguration(environment.getGatewayType());
-                    GatewayDeployer deployer = (GatewayDeployer) Class.forName(gatewayAgentConfiguration.getImplementation())
-                            .getDeclaredConstructor().newInstance();
-                    deployer.init(environment);
-                    return deployer;
+                    if (gatewayAgentConfiguration != null) {
+                        GatewayDeployer deployer = (GatewayDeployer) Class.forName(gatewayAgentConfiguration.getImplementation())
+                                .getDeclaredConstructor().newInstance();
+                        deployer.init(environment);
+                        return deployer;
+
+                    }
+                    return null;
                 }
             } catch (APIManagementException | ClassNotFoundException | NoSuchMethodException |
                      InstantiationException | IllegalAccessException | InvocationTargetException e) {

components/apimgt/org.wso2.carbon.apimgt.impl/src/main/java/org/wso2/carbon/apimgt/impl/notifier/ExternalGatewayNotifier.java

@@ -42,13 +42,12 @@
 import java.util.Set;
 
 public class ExternalGatewayNotifier extends DeployAPIInGatewayNotifier {
-    protected ApiMgtDAO apiMgtDAO;
+    protected ApiMgtDAO apiMgtDAO = ApiMgtDAO.getInstance();
     private static final Log log = LogFactory.getLog(ExternalGatewayNotifier.class);
 
     @Override
     public boolean publishEvent(Event event) throws NotifierException {
         if (APIUtil.isAnyExternalGateWayProviderExists(event.getTenantDomain())) {
-            apiMgtDAO = ApiMgtDAO.getInstance();
             process(event);
         }
         return true;