VOL-1838, VOL-1909, VOL-1906 and VOL-1911
Updated Device_handler.go test cases.
Adding Unit testcases for olt_platform.go, olt_event_mgr.go and statsmanager.go

Change-Id: I5b64df9a08fa20dd63bfd729c5f086526a9a1d74
diff --git a/mocks/mockOpenOltClient.go b/mocks/mockOpenOltClient.go
new file mode 100644
index 0000000..b3d9077
--- /dev/null
+++ b/mocks/mockOpenOltClient.go
@@ -0,0 +1,224 @@
+/*
+ * 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"
+	"io"
+
+	openolt "github.com/opencord/voltha-protos/go/openolt"
+	tech_profile "github.com/opencord/voltha-protos/go/tech_profile"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+)
+
+// MockOpenoltClient mock struct for OpenoltClient.
+type MockOpenoltClient struct {
+	counter int
+}
+
+// DisableOlt mocks the DisableOlt function of Openoltclient.
+func (ooc *MockOpenoltClient) DisableOlt(ctx context.Context, in *openolt.Empty, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	//return &openolt.Empty{}, nil
+	if ooc.counter == 0 {
+		ooc.counter++
+		return &openolt.Empty{}, nil
+	}
+	return nil, errors.New("disableOlt failed")
+}
+
+// ReenableOlt mocks the ReenableOlt function of Openoltclient.
+func (ooc *MockOpenoltClient) ReenableOlt(ctx context.Context, in *openolt.Empty, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	if ooc.counter == 0 {
+		ooc.counter++
+		return &openolt.Empty{}, nil
+	}
+	return nil, errors.New("reenable olt failed")
+}
+
+// ActivateOnu mocks the ActivateOnu function of Openoltclient.
+func (ooc *MockOpenoltClient) ActivateOnu(ctx context.Context, in *openolt.Onu, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	if in == nil {
+		return nil, errors.New("invalid onuId")
+	}
+	return &openolt.Empty{}, nil
+}
+
+// DeactivateOnu mocks the DeactivateOnu function of Openoltclient.
+func (ooc *MockOpenoltClient) DeactivateOnu(ctx context.Context, in *openolt.Onu, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	return &openolt.Empty{}, nil
+}
+
+// DeleteOnu mocks the DeleteOnu function of Openoltclient.
+func (ooc *MockOpenoltClient) DeleteOnu(ctx context.Context, in *openolt.Onu, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	return &openolt.Empty{}, nil
+}
+
+// OmciMsgOut mocks the OmciMsgOut function of Openoltclient.
+func (ooc *MockOpenoltClient) OmciMsgOut(ctx context.Context, in *openolt.OmciMsg, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	if in == nil {
+		return nil, errors.New("invalid Omci Msg")
+	}
+	return &openolt.Empty{}, nil
+}
+
+// OnuPacketOut mocks the OnuPacketOut function of Openoltclient.
+func (ooc *MockOpenoltClient) OnuPacketOut(ctx context.Context, in *openolt.OnuPacket, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	return &openolt.Empty{}, nil
+}
+
+// UplinkPacketOut mocks the UplinkPacketOut function of Openoltclient.
+func (ooc *MockOpenoltClient) UplinkPacketOut(ctx context.Context, in *openolt.UplinkPacket, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	return &openolt.Empty{}, nil
+}
+
+// FlowAdd mocks the FlowAdd function of Openoltclient.
+func (ooc *MockOpenoltClient) FlowAdd(ctx context.Context, in *openolt.Flow, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	return &openolt.Empty{}, nil
+}
+
+// FlowRemove mocks the FlowRemove function of Openoltclient.
+func (ooc *MockOpenoltClient) FlowRemove(ctx context.Context, in *openolt.Flow, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	return &openolt.Empty{}, nil
+}
+
+// HeartbeatCheck mocks the HeartbeatCheck function of Openoltclient.
+func (ooc *MockOpenoltClient) HeartbeatCheck(ctx context.Context, in *openolt.Empty, opts ...grpc.CallOption) (*openolt.Heartbeat, error) {
+	return nil, nil
+}
+
+// EnablePonIf mocks the EnablePonIf function of Openoltclient.
+func (ooc *MockOpenoltClient) EnablePonIf(ctx context.Context, in *openolt.Interface, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	return &openolt.Empty{}, nil
+}
+
+// DisablePonIf mocks the DisablePonIf function of Openoltclient.
+func (ooc *MockOpenoltClient) DisablePonIf(ctx context.Context, in *openolt.Interface, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	return &openolt.Empty{}, nil
+}
+
+// GetDeviceInfo mocks the GetDeviceInfo function of Openoltclient.
+func (ooc *MockOpenoltClient) GetDeviceInfo(ctx context.Context, in *openolt.Empty, opts ...grpc.CallOption) (*openolt.DeviceInfo, error) {
+	if ooc.counter == 0 {
+		ooc.counter++
+		deviceInfo := &openolt.DeviceInfo{Vendor: "Openolt", Model: "1.0", HardwareVersion: "1.0", FirmwareVersion: "1.0", DeviceId: "olt", DeviceSerialNumber: "olt"}
+		return deviceInfo, nil
+	}
+	if ooc.counter == 1 {
+		ooc.counter++
+		deviceInfo := &openolt.DeviceInfo{Vendor: "Openolt", Model: "1.0", HardwareVersion: "1.0", FirmwareVersion: "1.0", DeviceId: "", DeviceSerialNumber: "olt"}
+		return deviceInfo, nil
+	}
+	if ooc.counter == 2 {
+		ooc.counter++
+		return nil, nil
+	}
+
+	return nil, errors.New("device info not found")
+}
+
+// Reboot mocks the Reboot function of Openoltclient.
+func (ooc *MockOpenoltClient) Reboot(ctx context.Context, in *openolt.Empty, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	if ooc.counter == 0 {
+		ooc.counter++
+		return &openolt.Empty{}, nil
+	}
+	return nil, errors.New("reboot failed")
+}
+
+// CollectStatistics mocks the CollectStatistics function of Openoltclient.
+func (ooc *MockOpenoltClient) CollectStatistics(ctx context.Context, in *openolt.Empty, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	return &openolt.Empty{}, nil
+}
+
+// CreateTrafficSchedulers mocks the CreateTrafficSchedulers function of Openoltclient.
+func (ooc *MockOpenoltClient) CreateTrafficSchedulers(ctx context.Context, in *tech_profile.TrafficSchedulers, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	return &openolt.Empty{}, nil
+}
+
+// RemoveTrafficSchedulers mocks the RemoveTrafficSchedulers function of Openoltclient.
+func (ooc *MockOpenoltClient) RemoveTrafficSchedulers(ctx context.Context, in *tech_profile.TrafficSchedulers, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	return &openolt.Empty{}, nil
+}
+
+// CreateTrafficQueues mocks the CreateTrafficQueues function of Openoltclient.
+func (ooc *MockOpenoltClient) CreateTrafficQueues(ctx context.Context, in *tech_profile.TrafficQueues, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	return &openolt.Empty{}, nil
+}
+
+// RemoveTrafficQueues mocks the RemoveTrafficQueues function of Openoltclient.
+func (ooc *MockOpenoltClient) RemoveTrafficQueues(ctx context.Context, in *tech_profile.TrafficQueues, opts ...grpc.CallOption) (*openolt.Empty, error) {
+	return &openolt.Empty{}, nil
+}
+
+// EnableIndication mocks the EnableIndication function of Openoltclient.
+func (ooc *MockOpenoltClient) EnableIndication(ctx context.Context, in *openolt.Empty, opts ...grpc.CallOption) (openolt.Openolt_EnableIndicationClient, error) {
+	if ooc.counter < 2 {
+		ooc.counter++
+		mockInd := &mockOpenoltEnableIndicationClient{0}
+		return mockInd, nil
+	}
+	if ooc.counter == 2 {
+		ooc.counter++
+		return nil, nil
+	}
+	return nil, errors.New("invalid method invocation")
+}
+
+type mockOpenoltEnableIndicationClient struct {
+	count int
+}
+
+func (mock *mockOpenoltEnableIndicationClient) Recv() (*openolt.Indication, error) {
+	if mock.count == 0 {
+		mock.count = mock.count + 1
+		indi := &openolt.Indication{Data: &openolt.Indication_OltInd{OltInd: &openolt.OltIndication{OperState: "Down"}}}
+		return indi, nil
+	}
+	if mock.count == 1 {
+		mock.count = mock.count + 1
+		return nil, errors.New("error, while processing indication")
+	}
+
+	return nil, io.EOF
+}
+
+func (mock *mockOpenoltEnableIndicationClient) Header() (metadata.MD, error) {
+	return nil, nil
+}
+
+func (mock *mockOpenoltEnableIndicationClient) Trailer() metadata.MD {
+	return nil
+}
+
+func (mock *mockOpenoltEnableIndicationClient) CloseSend() error {
+	return nil
+}
+
+func (mock *mockOpenoltEnableIndicationClient) Context() context.Context {
+	return context.Background()
+}
+
+func (mock *mockOpenoltEnableIndicationClient) SendMsg(m interface{}) error {
+	return nil
+}
+
+func (mock *mockOpenoltEnableIndicationClient) RecvMsg(m interface{}) error {
+	return nil
+}