diff --git a/internal/pkg/core/openolt_test.go b/internal/pkg/core/openolt_test.go
new file mode 100644
index 0000000..5944db2
--- /dev/null
+++ b/internal/pkg/core/openolt_test.go
@@ -0,0 +1,985 @@
+/*
+ * 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.
+ */
+
+/*
+This file contains unit test cases for functions in the file openolt.go.
+This file also implements the fields struct to mock the Openolt and few utility functions.
+*/
+
+//Package core provides the utility for olt devices, flows and statistics
+package core
+
+import (
+	"context"
+	"errors"
+	com "github.com/opencord/voltha-lib-go/v3/pkg/adapters/common"
+	fu "github.com/opencord/voltha-lib-go/v3/pkg/flows"
+	"github.com/opencord/voltha-lib-go/v3/pkg/kafka"
+	"github.com/opencord/voltha-lib-go/v3/pkg/log"
+	"github.com/opencord/voltha-openolt-adapter/internal/pkg/config"
+	ic "github.com/opencord/voltha-protos/v3/go/inter_container"
+	"github.com/opencord/voltha-protos/v3/go/openflow_13"
+	ofp "github.com/opencord/voltha-protos/v3/go/openflow_13"
+	"github.com/opencord/voltha-protos/v3/go/voltha"
+	"reflect"
+	"sync"
+	"testing"
+)
+
+// mocks the OpenOLT struct.
+type fields struct {
+	deviceHandlers        map[string]*DeviceHandler
+	coreProxy             *com.CoreProxy
+	adapterProxy          *com.AdapterProxy
+	eventProxy            *com.EventProxy
+	kafkaICProxy          kafka.InterContainerProxy
+	numOnus               int
+	KVStoreHost           string
+	KVStorePort           int
+	KVStoreType           string
+	exitChannel           chan int
+	lockDeviceHandlersMap sync.RWMutex
+	ctx                   context.Context
+}
+
+// mockOlt mocks OpenOLT struct.
+func mockOlt() *fields {
+	dh := newMockDeviceHandler()
+	newOlt := &fields{}
+	newOlt.deviceHandlers = map[string]*DeviceHandler{}
+	newOlt.deviceHandlers[dh.device.Id] = dh
+	return newOlt
+}
+
+// testOltObject maps fields type to OpenOLt type.
+func testOltObject(testOlt *fields) *OpenOLT {
+	return &OpenOLT{
+		deviceHandlers: testOlt.deviceHandlers,
+		coreProxy:      testOlt.coreProxy,
+		adapterProxy:   testOlt.adapterProxy,
+		eventProxy:     testOlt.eventProxy,
+		kafkaICProxy:   testOlt.kafkaICProxy,
+		numOnus:        testOlt.numOnus,
+		KVStoreHost:    testOlt.KVStoreHost,
+		KVStorePort:    testOlt.KVStorePort,
+		KVStoreType:    testOlt.KVStoreType,
+		exitChannel:    testOlt.exitChannel,
+	}
+}
+
+// mockDevice mocks Device.
+func mockDevice() *voltha.Device {
+	device := &voltha.Device{
+		Id:       "olt",
+		Root:     true,
+		ParentId: "logical_device",
+		Ports: []*voltha.Port{
+			{PortNo: 1, Label: "pon"},
+			{PortNo: 2, Label: "nni"},
+		},
+		ProxyAddress: &voltha.Device_ProxyAddress{
+			DeviceId:       "olt",
+			DeviceType:     "onu",
+			ChannelId:      1,
+			ChannelGroupId: 1,
+		},
+		ConnectStatus: 1,
+	}
+	return device
+}
+
+func TestNewOpenOLT(t *testing.T) {
+	tests := []struct {
+		name        string
+		fields      *fields
+		configFlags *config.AdapterFlags
+		want        *OpenOLT
+	}{
+		{"newopenolt-1", &fields{}, &config.AdapterFlags{OnuNumber: 1, KVStorePort: 1, KVStoreType: "consul", KVStoreHost: "1.1.1.1"},
+			&OpenOLT{numOnus: 1, KVStorePort: 1, KVStoreType: "consul", KVStoreHost: "1.1.1.1"}},
+		{"newopenolt-2", &fields{}, &config.AdapterFlags{OnuNumber: 2, KVStorePort: 2, KVStoreType: "etcd", KVStoreHost: "2.2.2.2"},
+			&OpenOLT{numOnus: 2, KVStorePort: 2, KVStoreType: "etcd", KVStoreHost: "2.2.2.2"}},
+		{"newopenolt-3", &fields{}, &config.AdapterFlags{OnuNumber: 3, KVStorePort: 3, KVStoreType: "consul", KVStoreHost: "3.3.3.3"},
+			&OpenOLT{numOnus: 3, KVStorePort: 3, KVStoreType: "consul", KVStoreHost: "3.3.3.3"}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := NewOpenOLT(tt.fields.ctx, tt.fields.kafkaICProxy, tt.fields.coreProxy, tt.fields.adapterProxy,
+				tt.fields.eventProxy, tt.configFlags); reflect.TypeOf(got) != reflect.TypeOf(tt.want) && got != nil {
+				t.Errorf("NewOpenOLT() error = %v, wantErr %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Abandon_device(t *testing.T) {
+	type args struct {
+		device *voltha.Device
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"abandon_device-1", &fields{}, args{}, ErrNotImplemented},
+		{"abandon_device-2", &fields{}, args{}, ErrNotImplemented},
+		{"abandon_device-3", &fields{}, args{}, ErrNotImplemented},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Abandon_device(tt.args.device); err != tt.wantErr {
+				t.Errorf("Abandon_device() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Activate_image_update(t *testing.T) {
+	type args struct {
+		device  *voltha.Device
+		request *voltha.ImageDownload
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		want    *voltha.ImageDownload
+		wantErr error
+	}{
+		{"activate_image_upate-1", &fields{}, args{}, &voltha.ImageDownload{Id: "Image1-ABC123XYZ"},
+			ErrNotImplemented},
+		{"activate_image_upate-2", &fields{}, args{}, &voltha.ImageDownload{Id: "Image2-ABC123CDE"},
+			ErrNotImplemented},
+		{"activate_image_upate-3", &fields{}, args{}, &voltha.ImageDownload{Id: "Image3-ABC123EFG"},
+			ErrNotImplemented},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			got, err := oo.Activate_image_update(tt.args.device, tt.args.request)
+			if err != tt.wantErr && got == nil {
+				t.Errorf("Activate_image_update() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Adapter_descriptor(t *testing.T) {
+	tests := []struct {
+		name    string
+		fields  *fields
+		wantErr error
+	}{
+		{"adapter_descriptor-1", &fields{}, ErrNotImplemented},
+		{"adapter_descriptor-2", &fields{}, ErrNotImplemented},
+		{"adapter_descriptor-3", &fields{}, ErrNotImplemented},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Adapter_descriptor(); err != tt.wantErr {
+				t.Errorf("Adapter_descriptor() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Adopt_device(t *testing.T) {
+	type args struct {
+		device *voltha.Device
+	}
+	var device = mockDevice()
+	device.Id = "olt"
+	nilDevice := NewErrInvalidValue(log.Fields{"device": nil}, nil)
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"adopt_device-1", mockOlt(), args{}, nilDevice},
+		{"adopt_device-2", mockOlt(), args{device}, nilDevice},
+		{"adopt_device-3", mockOlt(), args{mockDevice()}, nil},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			err := oo.Adopt_device(tt.args.device)
+			if (err != nil) && (reflect.TypeOf(err) !=
+				reflect.TypeOf(tt.wantErr)) && (tt.args.device == nil) {
+				t.Errorf("Adopt_device() error = %v, wantErr %v", err, tt.wantErr)
+			}
+			if err == nil {
+				t.Log("return'd nil")
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Cancel_image_download(t *testing.T) {
+	type args struct {
+		device  *voltha.Device
+		request *voltha.ImageDownload
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		want    *voltha.ImageDownload
+		wantErr error
+	}{
+		{"cancel_image_download-1", &fields{}, args{}, &voltha.ImageDownload{Id: "Image1-ABC123XYZ"},
+			ErrNotImplemented},
+		{"cancel_image_download-2", &fields{}, args{}, &voltha.ImageDownload{Id: "Image2-ABC123IJK"},
+			ErrNotImplemented},
+		{"cancel_image_download-3", &fields{}, args{}, &voltha.ImageDownload{Id: "Image3-ABC123KLM"},
+			ErrNotImplemented},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			got, err := oo.Cancel_image_download(tt.args.device, tt.args.request)
+			if err != tt.wantErr && got == nil {
+				t.Errorf("Cancel_image_download() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Delete_device(t *testing.T) {
+	type args struct {
+		device *voltha.Device
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"delete_device-1", &fields{}, args{mockDevice()},
+			NewErrNotFound("device-handler", log.Fields{"device-id": "olt"}, nil)},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Delete_device(tt.args.device); !reflect.DeepEqual(err, tt.wantErr) {
+				t.Errorf("Delete_device() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Device_types(t *testing.T) {
+	tests := []struct {
+		name    string
+		fields  *fields
+		want    *voltha.DeviceTypes
+		wantErr error
+	}{
+		{"device_types-1", &fields{}, &voltha.DeviceTypes{},
+			ErrNotImplemented},
+		{"device_types-2", &fields{}, &voltha.DeviceTypes{},
+			ErrNotImplemented},
+		{"device_types-3", &fields{}, &voltha.DeviceTypes{},
+			ErrNotImplemented},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			got, err := oo.Device_types()
+			if err != tt.wantErr && got == nil {
+				t.Errorf("Device_types() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Disable_device(t *testing.T) {
+	type args struct {
+		device *voltha.Device
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"disable_device-1", mockOlt(), args{mockDevice()}, nil},
+		{"disable_device-2", &fields{}, args{mockDevice()},
+			NewErrNotFound("device-handler", log.Fields{"device-id": "olt"}, nil)},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Disable_device(tt.args.device); !reflect.DeepEqual(err, tt.wantErr) {
+				t.Errorf("Disable_device() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Download_image(t *testing.T) {
+	type args struct {
+		device  *voltha.Device
+		request *voltha.ImageDownload
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		want    *voltha.ImageDownload
+		wantErr error
+	}{
+		{"download_image-1", &fields{}, args{}, &voltha.ImageDownload{Id: "Image1-ABC123XYZ"},
+			ErrNotImplemented},
+		{"download_image-2", &fields{}, args{}, &voltha.ImageDownload{Id: "Image2-ABC123LKJ"},
+			ErrNotImplemented},
+		{"download_image-3", &fields{}, args{}, &voltha.ImageDownload{Id: "Image1-ABC123RTY"},
+			ErrNotImplemented},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			got, err := oo.Download_image(tt.args.device, tt.args.request)
+			if err != tt.wantErr && got == nil {
+				t.Errorf("Download_image() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Get_device_details(t *testing.T) {
+	type args struct {
+		device *voltha.Device
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"get_device_details-1", &fields{}, args{}, ErrNotImplemented},
+		{"get_device_details-2", &fields{}, args{}, ErrNotImplemented},
+		{"get_device_details-3", &fields{}, args{}, ErrNotImplemented},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Get_device_details(tt.args.device); err != tt.wantErr {
+				t.Errorf("Get_device_details() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Get_image_download_status(t *testing.T) {
+	type args struct {
+		device  *voltha.Device
+		request *voltha.ImageDownload
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		want    *voltha.ImageDownload
+		wantErr error
+	}{
+		{"get_image_download_status-1", &fields{}, args{}, &voltha.ImageDownload{Id: "Image1-ABC123XYZ"},
+			ErrNotImplemented},
+		{"get_image_download_status-2", &fields{}, args{}, &voltha.ImageDownload{Id: "Image2-ABC123LKJ"},
+			ErrNotImplemented},
+		{"get_image_download_status-3", &fields{}, args{}, &voltha.ImageDownload{Id: "Image1-ABC123DFG"},
+			ErrNotImplemented},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			got, err := oo.Get_image_download_status(tt.args.device, tt.args.request)
+			if err != tt.wantErr && got == nil {
+				t.Errorf("Get_image_download_status() got = %v want = %v error = %v, wantErr %v",
+					got, tt.want, err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Get_ofp_device_info(t *testing.T) {
+	type args struct {
+		device *voltha.Device
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		want    *ic.SwitchCapability
+		wantErr error
+	}{
+		{"get_ofp_device_info-1", mockOlt(), args{mockDevice()}, &ic.SwitchCapability{
+			Desc: &openflow_13.OfpDesc{
+				MfrDesc: "VOLTHA Project",
+				HwDesc:  "open_pon",
+				SwDesc:  "open_pon",
+			},
+			SwitchFeatures: &openflow_13.OfpSwitchFeatures{
+				NBuffers:     uint32(256),
+				NTables:      uint32(2),
+				Capabilities: uint32(15),
+			},
+		}, nil},
+		{"get_ofp_device_info-2", &fields{}, args{mockDevice()}, nil,
+			NewErrNotFound("device-handler", log.Fields{"device-id": "olt"}, nil)},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			got, err := oo.Get_ofp_device_info(tt.args.device)
+			if !reflect.DeepEqual(err, tt.wantErr) || !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("Get_ofp_device_info() got = %v want = %v error = %v, wantErr = %v",
+					got, tt.want, err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Get_ofp_port_info(t *testing.T) {
+	type args struct {
+		device *voltha.Device
+		portNo int64
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		want    *ic.PortCapability
+		wantErr error
+	}{
+		{"get_ofp_port_info-1", mockOlt(), args{mockDevice(), 1}, &ic.PortCapability{
+			Port: &voltha.LogicalPort{
+				DeviceId:     "olt",
+				DevicePortNo: uint32(1),
+				OfpPort: &openflow_13.OfpPort{
+					HwAddr:     []uint32{1, 2, 3, 4, 5, 6},
+					State:      uint32(4),
+					Curr:       uint32(4128),
+					Advertised: uint32(4128),
+					Peer:       uint32(4128),
+					CurrSpeed:  uint32(32),
+					MaxSpeed:   uint32(32),
+				},
+			},
+		}, nil},
+		{"get_ofp_port_info-2", &fields{}, args{mockDevice(), 1}, nil,
+			NewErrNotFound("device-handler", log.Fields{"device-id": "olt"}, nil)},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			got, err := oo.Get_ofp_port_info(tt.args.device, tt.args.portNo)
+			if !reflect.DeepEqual(err, tt.wantErr) || !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("Get_ofp_port_info() got = %v want = %v error = %v, wantErr = %v",
+					got, tt.want, err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Health(t *testing.T) {
+	tests := []struct {
+		name    string
+		fields  *fields
+		want    *voltha.HealthStatus
+		wantErr error
+	}{
+		{"health-1", &fields{}, &voltha.HealthStatus{}, ErrNotImplemented},
+		{"health-2", &fields{}, &voltha.HealthStatus{}, ErrNotImplemented},
+		{"health-3", &fields{}, &voltha.HealthStatus{}, ErrNotImplemented},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			got, err := oo.Health()
+			if err != tt.wantErr && got == nil {
+				t.Errorf("Get_ofp_port_info() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Process_inter_adapter_message(t *testing.T) {
+	type args struct {
+		msg *ic.InterAdapterMessage
+	}
+	var message1 = args{
+		msg: &ic.InterAdapterMessage{
+			Header: &ic.InterAdapterHeader{
+				Id:            "olt",
+				ProxyDeviceId: "",
+				ToDeviceId:    "onu1",
+			},
+		},
+	}
+	var message2 = args{
+		msg: &ic.InterAdapterMessage{
+			Header: &ic.InterAdapterHeader{
+				Id:            "olt",
+				ProxyDeviceId: "olt",
+				ToDeviceId:    "olt",
+				Type:          ic.InterAdapterMessageType_OMCI_REQUEST,
+			},
+		},
+	}
+	var message3 = args{
+		msg: &ic.InterAdapterMessage{
+			Header: &ic.InterAdapterHeader{
+				Id:            "olt",
+				ProxyDeviceId: "olt",
+				ToDeviceId:    "olt",
+				Type:          ic.InterAdapterMessageType_FLOW_REQUEST,
+			},
+		},
+	}
+	tests := []struct {
+		name        string
+		fields      *fields
+		args        args
+		wantErrType reflect.Type
+	}{
+		{"process_inter_adaptor_messgae-1", mockOlt(), message1,
+			reflect.TypeOf(&ErrNotFound{})},
+		{"process_inter_adaptor_messgae-2", mockOlt(), message2,
+			reflect.TypeOf(errors.New("message is nil"))},
+		{"process_inter_adaptor_messgae-3", mockOlt(), message3,
+			reflect.TypeOf(&ErrInvalidValue{})},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Process_inter_adapter_message(tt.args.msg); reflect.TypeOf(err) != tt.wantErrType {
+				t.Errorf("Process_inter_adapter_message() error = %v, wantErr %v",
+					reflect.TypeOf(err), tt.wantErrType)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Reboot_device(t *testing.T) {
+	type args struct {
+		device *voltha.Device
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"reboot_device-1", mockOlt(), args{mockDevice()}, nil},
+		{"reboot_device-2", &fields{}, args{mockDevice()},
+			NewErrNotFound("device-handler", log.Fields{"device-id": "olt"}, nil)},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Reboot_device(tt.args.device); !reflect.DeepEqual(err, tt.wantErr) {
+				t.Errorf("Reboot_device() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Receive_packet_out(t *testing.T) {
+	acts := []*ofp.OfpAction{
+		fu.SetField(fu.Metadata_ofp(uint64(ofp.OfpInstructionType_OFPIT_WRITE_METADATA))),
+		fu.SetField(fu.VlanVid(uint32(ofp.OfpVlanId_OFPVID_PRESENT) | 101)),
+		fu.Output(1),
+	}
+	type args struct {
+		deviceID     string
+		egressPortNo int
+		packet       *openflow_13.OfpPacketOut
+	}
+	pktout := &ofp.OfpPacketOut{BufferId: 0, InPort: 1, Actions: acts, Data: []byte("AYDCAAAOAODsSE5TiMwCBwQA4OxITlIEBQUwLzUx" +
+		"BgIAFAgEMC81MQoJbG9jYWxob3N0EBwFAawbqqACAAAAoRAxLjMuNi4xLjQuMS40NDEz/gYAgMILAgD+GQCAwgkDAAAAAGQAAAAAAAAAAgICAgICAgL+" +
+		"GQCAwgoDAAAAAGQAAAAAAAAAAgICAgICAgIAAA==")}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"receive_packet_out-1", mockOlt(), args{mockDevice().Id, 1, pktout}, nil},
+		{"receive_packet_out-2", mockOlt(), args{"1234", 1, pktout},
+			NewErrNotFound("device-handler", log.Fields{"device-id": "1234"}, nil)},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Receive_packet_out(tt.args.deviceID, tt.args.egressPortNo, tt.args.packet); !reflect.DeepEqual(err, tt.wantErr) {
+				t.Errorf("Receive_packet_out() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Reconcile_device(t *testing.T) {
+	type args struct {
+		device *voltha.Device
+	}
+	expectedError := NewErrInvalidValue(log.Fields{"device": nil}, nil)
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"reconcile_device-1", &fields{}, args{}, expectedError},
+		{"reconcile_device-2", &fields{}, args{}, expectedError},
+		{"reconcile_device-3", &fields{}, args{}, expectedError},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Reconcile_device(tt.args.device); !reflect.DeepEqual(err, tt.wantErr) {
+				t.Errorf("Reconcile_device() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Reenable_device(t *testing.T) {
+	type args struct {
+		device *voltha.Device
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"reenable_device-1", mockOlt(), args{mockDevice()}, nil},
+		{"reenable_device-2", &fields{}, args{mockDevice()},
+			NewErrNotFound("device-handler", log.Fields{"device-id": "olt"}, nil)},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Reenable_device(tt.args.device); !reflect.DeepEqual(err, tt.wantErr) {
+				t.Errorf("Reenable_device() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Revert_image_update(t *testing.T) {
+	type args struct {
+		device  *voltha.Device
+		request *voltha.ImageDownload
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		want    *voltha.ImageDownload
+		wantErr error
+	}{
+		{"revert_image_update-1", &fields{}, args{}, &voltha.ImageDownload{Id: "Image1-ABC123XYZ"},
+			ErrNotImplemented},
+		{"revert_image_update-2", &fields{}, args{}, &voltha.ImageDownload{Id: "Image2-ABC123TYU"},
+			ErrNotImplemented},
+		{"revert_image_update-3", &fields{}, args{}, &voltha.ImageDownload{Id: "Image3-ABC123GTH"},
+			ErrNotImplemented},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			got, err := oo.Revert_image_update(tt.args.device, tt.args.request)
+			if err != tt.wantErr && got == nil {
+				t.Log("error :", err)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Self_test_device(t *testing.T) {
+	type args struct {
+		device *voltha.Device
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"self_test_device-1", &fields{}, args{}, ErrNotImplemented},
+		{"self_test_device-2", &fields{}, args{}, ErrNotImplemented},
+		{"self_test_device-3", &fields{}, args{}, ErrNotImplemented},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Self_test_device(tt.args.device); err != tt.wantErr {
+				t.Errorf("Self_test_device() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Start(t *testing.T) {
+	type args struct {
+		ctx context.Context
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"start-1", &fields{}, args{}, errors.New("start error")},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Start(tt.args.ctx); err != nil {
+				t.Errorf("Start() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Stop(t *testing.T) {
+	type args struct {
+		ctx context.Context
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"stop-1", &fields{exitChannel: make(chan int, 1)}, args{}, errors.New("stop error")},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			oo.Start(tt.args.ctx)
+			if err := oo.Stop(tt.args.ctx); err != nil {
+				t.Errorf("Stop() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Suppress_event(t *testing.T) {
+	type args struct {
+		filter *voltha.EventFilter
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"suppress_event-1", &fields{}, args{}, ErrNotImplemented},
+		{"suppress_event-2", &fields{}, args{}, ErrNotImplemented},
+		{"suppress_event-3", &fields{}, args{}, ErrNotImplemented},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Suppress_event(tt.args.filter); err != tt.wantErr {
+				t.Errorf("Suppress_event() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Unsuppress_event(t *testing.T) {
+	type args struct {
+		filter *voltha.EventFilter
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"unsupress_event-1", &fields{}, args{}, ErrNotImplemented},
+		{"unsupress_event-2", &fields{}, args{}, ErrNotImplemented},
+		{"unsupress_event-3", &fields{}, args{}, ErrNotImplemented},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Unsuppress_event(tt.args.filter); err != tt.wantErr {
+				t.Errorf("Unsuppress_event() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Update_flows_bulk(t *testing.T) {
+	type args struct {
+		device       *voltha.Device
+		flows        *voltha.Flows
+		groups       *voltha.FlowGroups
+		flowMetadata *voltha.FlowMetadata
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"update_flows_bulk-1", &fields{}, args{}, ErrNotImplemented},
+		{"update_flows_bulk-2", &fields{}, args{}, ErrNotImplemented},
+		{"update_flows_bulk-3", &fields{}, args{}, ErrNotImplemented},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Update_flows_bulk(tt.args.device, tt.args.flows, tt.args.groups, tt.args.flowMetadata); err != tt.wantErr {
+				t.Errorf("Update_flows_bulk() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Update_flows_incrementally(t *testing.T) {
+	type args struct {
+		device       *voltha.Device
+		flows        *openflow_13.FlowChanges
+		groups       *openflow_13.FlowGroupChanges
+		flowMetadata *voltha.FlowMetadata
+	}
+
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"update_flows_incrementally-1", &fields{}, args{device: mockDevice()},
+			NewErrNotFound("device-handler", log.Fields{"device-id": "olt"}, nil)},
+		{"update_flows_incrementally-2", mockOlt(), args{device: mockDevice()}, nil},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Update_flows_incrementally(tt.args.device, tt.args.flows, tt.args.groups, tt.args.flowMetadata); !reflect.DeepEqual(err, tt.wantErr) {
+				t.Errorf("Update_flows_incrementally() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Update_pm_config(t *testing.T) {
+	type args struct {
+		device    *voltha.Device
+		pmConfigs *voltha.PmConfigs
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr error
+	}{
+		{"update_pm_config-1", &fields{}, args{}, ErrNotImplemented},
+		{"update_pm_config-2", &fields{}, args{}, ErrNotImplemented},
+		{"update_pm_config-3", &fields{}, args{}, ErrNotImplemented},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Update_pm_config(tt.args.device, tt.args.pmConfigs); err != tt.wantErr {
+				t.Errorf("Update_pm_config() error = %v, wantErr %v", err, tt.wantErr)
+			}
+
+		})
+	}
+}
+
+func TestOpenOLT_deleteDeviceHandlerToMap(t *testing.T) {
+	type args struct {
+		agent *DeviceHandler
+	}
+	tests := []struct {
+		name   string
+		fields *fields
+		args   args
+	}{
+		{"delete_device_handler_map-1", mockOlt(), args{newMockDeviceHandler()}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			oo.deleteDeviceHandlerToMap(tt.args.agent)
+			if len(oo.deviceHandlers) > 0 {
+				t.Errorf("delete device manager failed")
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Enable_port(t *testing.T) {
+	type args struct {
+		deviceID string
+		port     *voltha.Port
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr bool
+	}{
+		// TODO: Add test cases.
+		{"Enable_port-1", mockOlt(), args{deviceID: "olt", port: &voltha.Port{Type: voltha.Port_PON_OLT, PortNo: 1}}, false},
+		{"Enable_port-2", mockOlt(), args{deviceID: "olt", port: &voltha.Port{Type: voltha.Port_ETHERNET_NNI, PortNo: 1}}, true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Enable_port(tt.args.deviceID, tt.args.port); (err != nil) != tt.wantErr {
+				t.Errorf("OpenOLT.Enable_port() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestOpenOLT_Disable_port(t *testing.T) {
+	type args struct {
+		deviceID string
+		port     *voltha.Port
+	}
+	tests := []struct {
+		name    string
+		fields  *fields
+		args    args
+		wantErr bool
+	}{
+		// TODO: Add test cases.
+		{"Disable_port-1", mockOlt(), args{deviceID: "olt", port: &voltha.Port{Type: voltha.Port_PON_OLT, PortNo: 1}}, false},
+		{"Disable_port-2", mockOlt(), args{deviceID: "olt", port: &voltha.Port{Type: voltha.Port_ETHERNET_NNI, PortNo: 1}}, true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oo := testOltObject(tt.fields)
+			if err := oo.Disable_port(tt.args.deviceID, tt.args.port); (err != nil) != tt.wantErr {
+				t.Errorf("OpenOLT.Disable_port() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}