unit tests for NetconfSessionImpl

Change-Id: Ic1b7d0221343f288b98c41f456809b59689e198f
diff --git a/protocols/netconf/ctl/src/main/java/org/onosproject/netconf/ctl/NetconfSessionImpl.java b/protocols/netconf/ctl/src/main/java/org/onosproject/netconf/ctl/NetconfSessionImpl.java
index 07afac8..7da836c 100644
--- a/protocols/netconf/ctl/src/main/java/org/onosproject/netconf/ctl/NetconfSessionImpl.java
+++ b/protocols/netconf/ctl/src/main/java/org/onosproject/netconf/ctl/NetconfSessionImpl.java
@@ -399,12 +399,12 @@
 
     @Override
     public String getConfig(String netconfTargetConfig) throws NetconfException {
-        return getConfig(TargetConfig.valueOf(netconfTargetConfig));
+        return getConfig(TargetConfig.toTargetConfig(netconfTargetConfig));
     }
 
     @Override
     public String getConfig(String netconfTargetConfig, String configurationFilterSchema) throws NetconfException {
-        return getConfig(TargetConfig.valueOf(netconfTargetConfig), configurationFilterSchema);
+        return getConfig(TargetConfig.toTargetConfig(netconfTargetConfig), configurationFilterSchema);
     }
 
     @Override
@@ -442,7 +442,7 @@
     @Override
     public boolean editConfig(String netconfTargetConfig, String mode, String newConfiguration)
             throws NetconfException {
-        return editConfig(TargetConfig.valueOf(netconfTargetConfig), mode, newConfiguration);
+        return editConfig(TargetConfig.toTargetConfig(netconfTargetConfig), mode, newConfiguration);
     }
 
     @Override
@@ -479,7 +479,7 @@
 
     @Override
     public boolean copyConfig(String netconfTargetConfig, String newConfiguration) throws NetconfException {
-        return copyConfig(TargetConfig.valueOf(netconfTargetConfig), newConfiguration);
+        return copyConfig(TargetConfig.toTargetConfig(netconfTargetConfig), newConfiguration);
     }
 
     @Override
@@ -508,12 +508,12 @@
 
     @Override
     public boolean deleteConfig(String netconfTargetConfig) throws NetconfException {
-        return deleteConfig(TargetConfig.valueOf(netconfTargetConfig));
+        return deleteConfig(TargetConfig.toTargetConfig(netconfTargetConfig));
     }
 
     @Override
     public boolean deleteConfig(TargetConfig netconfTargetConfig) throws NetconfException {
-        if (netconfTargetConfig.equals("running")) {
+        if (netconfTargetConfig.equals(TargetConfig.RUNNING)) {
             log.warn("Target configuration for delete operation can't be \"running\"",
                      netconfTargetConfig);
             return false;