VOL-1838 Unit test cases for golang openolt adapter device_handler.go
1.Mocked AdapterproxyIntf and coreproxyIntf Interfaces for unit test cases.
2. Added few unit testcases for the device_handler.go functions

Change-Id: I793d94055d2c0480e614e918c064df51cdf0b0ae
diff --git a/mocks/mockAdapterProxy.go b/mocks/mockAdapterProxy.go
new file mode 100644
index 0000000..a91d361
--- /dev/null
+++ b/mocks/mockAdapterProxy.go
@@ -0,0 +1,47 @@
+/*
+ * Copyright 2018-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 mocks provides the mocks for openolt-adapter.
+package mocks
+
+import (
+	"context"
+	"errors"
+
+	"github.com/golang/protobuf/proto"
+	"github.com/opencord/voltha-protos/go/inter_container"
+)
+
+// MockAdapterProxy mocks the AdapterProxy interface.
+type MockAdapterProxy struct {
+}
+
+// SendInterAdapterMessage mocks SendInterAdapterMessage function.
+func (ma *MockAdapterProxy) SendInterAdapterMessage(ctx context.Context,
+	msg proto.Message,
+	msgType inter_container.InterAdapterMessageType_Types,
+	fromAdapter string,
+	toAdapter string,
+	toDeviceID string,
+	proxyDeviceID string,
+	messageID string) error {
+	//panic("implement me")
+	if ctx == nil || msg == nil || fromAdapter != "" ||
+		toAdapter != "" || toDeviceID != "" || proxyDeviceID != "" || messageID != "" {
+		return errors.New("sendInterAdapterMessage func parameters cannot be nil")
+	}
+	return nil
+}