Add upgrade event listener to UpgradeService on initialization of MastershipManager

Change-Id: Ic1d419d1c5908bddee633897391fa6ef11c525b3
diff --git a/core/net/src/test/java/org/onosproject/upgrade/impl/UpgradeServiceAdapter.java b/core/net/src/test/java/org/onosproject/upgrade/impl/UpgradeServiceAdapter.java
new file mode 100644
index 0000000..cd327c4
--- /dev/null
+++ b/core/net/src/test/java/org/onosproject/upgrade/impl/UpgradeServiceAdapter.java
@@ -0,0 +1,61 @@
+/*
+ * Copyright 2017-present Open Networking Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.upgrade.impl;
+
+import org.onosproject.core.Version;
+import org.onosproject.upgrade.Upgrade;
+import org.onosproject.upgrade.UpgradeEventListener;
+import org.onosproject.upgrade.UpgradeService;
+
+/**
+ * Upgrade service adapter.
+ */
+public class UpgradeServiceAdapter implements UpgradeService {
+    @Override
+    public boolean isUpgrading() {
+        return false;
+    }
+
+    @Override
+    public Upgrade getState() {
+        return null;
+    }
+
+    @Override
+    public Version getVersion() {
+        return null;
+    }
+
+    @Override
+    public boolean isLocalActive() {
+        return false;
+    }
+
+    @Override
+    public boolean isLocalUpgraded() {
+        return false;
+    }
+
+    @Override
+    public void addListener(UpgradeEventListener listener) {
+
+    }
+
+    @Override
+    public void removeListener(UpgradeEventListener listener) {
+
+    }
+}