diff --git a/pkg/mocks/mockCoreClient.go b/pkg/mocks/mockCoreClient.go
new file mode 100644
index 0000000..bc0e0a2
--- /dev/null
+++ b/pkg/mocks/mockCoreClient.go
@@ -0,0 +1,259 @@
+/*
+ * Copyright 2021-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"
+	"fmt"
+	"strings"
+
+	"github.com/golang/protobuf/ptypes/empty"
+	vgrpc "github.com/opencord/voltha-lib-go/v7/pkg/grpc"
+	"github.com/opencord/voltha-protos/v5/go/common"
+	ic "github.com/opencord/voltha-protos/v5/go/inter_container"
+	"github.com/opencord/voltha-protos/v5/go/voltha"
+	"google.golang.org/grpc"
+)
+
+// NewMockCoreClient creates a new mock core client for a given core service
+func NewMockCoreClient(coreService *MockCoreService) *vgrpc.Client {
+	cc, _ := vgrpc.NewClient("mock-endpoint", nil)
+	cc.SetService(coreService)
+	return cc
+}
+
+// MockCoreService represents a mock core service
+type MockCoreService struct {
+	// Values to be used in test can reside inside this structure
+	// TODO store relevant info in this, use this info for negative and positive tests
+	Devices     map[string]*voltha.Device
+	DevicePorts map[string][]*voltha.Port
+}
+
+// GetHealthStatus implements mock GetHealthStatus
+func (mcs MockCoreService) GetHealthStatus(ctx context.Context, in *empty.Empty, opts ...grpc.CallOption) (*voltha.HealthStatus, error) {
+	return &voltha.HealthStatus{State: voltha.HealthStatus_HEALTHY}, nil
+}
+
+// RegisterAdapter implements mock RegisterAdapter
+func (mcs MockCoreService) RegisterAdapter(ctx context.Context, in *ic.AdapterRegistration, opts ...grpc.CallOption) (*empty.Empty, error) {
+	if ctx == nil || in.Adapter == nil || in.DTypes == nil {
+		return nil, errors.New("registerAdapter func parameters cannot be nil")
+	}
+	return &empty.Empty{}, nil
+}
+
+// DeviceUpdate implements mock DeviceUpdate
+func (mcs MockCoreService) DeviceUpdate(ctx context.Context, in *voltha.Device, opts ...grpc.CallOption) (*empty.Empty, error) {
+	if in.Id == "" {
+		return nil, errors.New("no Device")
+	}
+	return &empty.Empty{}, nil
+}
+
+// PortCreated implements mock PortCreated
+func (mcs MockCoreService) PortCreated(ctx context.Context, in *voltha.Port, opts ...grpc.CallOption) (*empty.Empty, error) {
+	if in.DeviceId == "" {
+		return nil, errors.New("no deviceID")
+	}
+	if in.Type > 7 {
+		return nil, errors.New("invalid porttype")
+	}
+	return &empty.Empty{}, nil
+}
+
+// PortsStateUpdate implements mock PortsStateUpdate
+func (mcs MockCoreService) PortsStateUpdate(ctx context.Context, in *ic.PortStateFilter, opts ...grpc.CallOption) (*empty.Empty, error) {
+	if in.DeviceId == "" {
+		return nil, errors.New("no Device")
+	}
+	return &empty.Empty{}, nil
+}
+
+// DeleteAllPorts implements mock DeleteAllPorts
+func (mcs MockCoreService) DeleteAllPorts(ctx context.Context, in *common.ID, opts ...grpc.CallOption) (*empty.Empty, error) {
+	if in.Id == "" {
+		return nil, errors.New("no Device id")
+	}
+	return &empty.Empty{}, nil
+}
+
+// GetDevicePort implements mock GetDevicePort
+func (mcs MockCoreService) GetDevicePort(ctx context.Context, in *ic.PortFilter, opts ...grpc.CallOption) (*voltha.Port, error) {
+	for _, port := range mcs.DevicePorts[in.DeviceId] {
+		if port.PortNo == in.Port {
+			return port, nil
+		}
+	}
+	return nil, errors.New("device/port not found")
+}
+
+// ListDevicePorts implements mock ListDevicePorts
+func (mcs MockCoreService) ListDevicePorts(ctx context.Context, in *common.ID, opts ...grpc.CallOption) (*voltha.Ports, error) {
+	ports, have := mcs.DevicePorts[in.Id]
+	if !have {
+		return nil, errors.New("device id not found")
+	}
+	return &voltha.Ports{Items: ports}, nil
+}
+
+// DeviceStateUpdate implements mock DeviceStateUpdate
+func (mcs MockCoreService) DeviceStateUpdate(ctx context.Context, in *ic.DeviceStateFilter, opts ...grpc.CallOption) (*empty.Empty, error) {
+	if in.DeviceId == "" {
+		return nil, errors.New("no Device id")
+	}
+	return &empty.Empty{}, nil
+}
+
+// DevicePMConfigUpdate implements mock DevicePMConfigUpdate
+func (mcs MockCoreService) DevicePMConfigUpdate(ctx context.Context, in *voltha.PmConfigs, opts ...grpc.CallOption) (*empty.Empty, error) {
+	return &empty.Empty{}, nil
+}
+
+// ChildDeviceDetected implements mock ChildDeviceDetected
+func (mcs MockCoreService) ChildDeviceDetected(ctx context.Context, in *ic.DeviceDiscovery, opts ...grpc.CallOption) (*voltha.Device, error) {
+	if in.ParentId == "" {
+		return nil, errors.New("no deviceID")
+	}
+	for k, v := range mcs.Devices {
+		if strings.Contains(k, "onu") {
+			return v, nil
+		}
+	}
+	return nil, errors.New("no deviceID")
+}
+
+// ChildDevicesLost implements mock ChildDevicesLost
+func (mcs MockCoreService) ChildDevicesLost(ctx context.Context, in *common.ID, opts ...grpc.CallOption) (*empty.Empty, error) {
+	if in.Id == "" {
+		return nil, errors.New("no device id")
+	}
+	return &empty.Empty{}, nil
+}
+
+// ChildDevicesDetected implements mock ChildDevicesDetected
+func (mcs MockCoreService) ChildDevicesDetected(ctx context.Context, in *common.ID, opts ...grpc.CallOption) (*empty.Empty, error) {
+	if in.Id == "" {
+		return nil, errors.New("no device id")
+	}
+	return &empty.Empty{}, nil
+}
+
+// GetDevice implements mock GetDevice
+func (mcs MockCoreService) GetDevice(ctx context.Context, in *common.ID, opts ...grpc.CallOption) (*voltha.Device, error) {
+	if in.Id == "" {
+		return &voltha.Device{}, errors.New("no deviceID")
+	}
+	for k, v := range mcs.Devices {
+		if k == "olt" {
+			return v, nil
+		}
+	}
+	return nil, errors.New("device detection failed")
+}
+
+// GetChildDevice implements mock GetChildDevice
+func (mcs MockCoreService) GetChildDevice(ctx context.Context, in *ic.ChildDeviceFilter, opts ...grpc.CallOption) (*voltha.Device, error) {
+	if in.ParentId == "" {
+		return nil, errors.New("device detection failed")
+	}
+	var onuDevice *voltha.Device
+	for _, val := range mcs.Devices {
+		if val.GetId() == fmt.Sprintf("%d", in.OnuId) {
+			onuDevice = val
+			break
+		}
+	}
+	if onuDevice != nil {
+		return onuDevice, nil
+	}
+	//return &voltha.Device{}, nil
+	return nil, errors.New("device detection failed")
+}
+
+// GetChildDevices implements mock GetChildDevices
+func (mcs MockCoreService) GetChildDevices(ctx context.Context, in *common.ID, opts ...grpc.CallOption) (*voltha.Devices, error) {
+	if in.Id == "" {
+		return nil, errors.New("no deviceID")
+	}
+	onuDevices := make([]*voltha.Device, 0)
+
+	for _, val := range mcs.Devices {
+		if val != nil && val.ParentId == in.Id {
+			onuDevices = append(onuDevices, val)
+		}
+	}
+
+	deviceList := &voltha.Devices{Items: onuDevices}
+	if len(deviceList.Items) > 0 {
+		return deviceList, nil
+	}
+	return nil, errors.New("device detection failed")
+}
+
+// SendPacketIn implements mock SendPacketIn
+func (mcs MockCoreService) SendPacketIn(ctx context.Context, in *ic.PacketIn, opts ...grpc.CallOption) (*empty.Empty, error) {
+	if in.DeviceId == "" {
+		return nil, errors.New("no Device ID")
+	}
+	return &empty.Empty{}, nil
+}
+
+// DeviceReasonUpdate implements mock DeviceReasonUpdate
+func (mcs MockCoreService) DeviceReasonUpdate(ctx context.Context, in *ic.DeviceReason, opts ...grpc.CallOption) (*empty.Empty, error) {
+	if in.DeviceId == "" {
+		return nil, errors.New("no Device ID")
+	}
+	return &empty.Empty{}, nil
+}
+
+// PortStateUpdate implements mock PortStateUpdate
+func (mcs MockCoreService) PortStateUpdate(ctx context.Context, in *ic.PortState, opts ...grpc.CallOption) (*empty.Empty, error) {
+	if in.DeviceId == "" {
+		return nil, errors.New("no Device")
+	}
+	return &empty.Empty{}, nil
+}
+
+// Additional API found in the Core - unused?
+
+// ReconcileChildDevices implements mock ReconcileChildDevices
+func (mcs MockCoreService) ReconcileChildDevices(ctx context.Context, in *common.ID, opts ...grpc.CallOption) (*empty.Empty, error) {
+	return &empty.Empty{}, nil
+}
+
+// GetChildDeviceWithProxyAddress implements mock GetChildDeviceWithProxyAddress
+func (mcs MockCoreService) GetChildDeviceWithProxyAddress(ctx context.Context, in *voltha.Device_ProxyAddress, opts ...grpc.CallOption) (*voltha.Device, error) {
+	return nil, nil
+}
+
+// GetPorts implements mock GetPorts
+func (mcs MockCoreService) GetPorts(ctx context.Context, in *ic.PortFilter, opts ...grpc.CallOption) (*voltha.Ports, error) {
+	return nil, nil
+}
+
+// ChildrenStateUpdate implements mock ChildrenStateUpdate
+func (mcs MockCoreService) ChildrenStateUpdate(ctx context.Context, in *ic.DeviceStateFilter, opts ...grpc.CallOption) (*empty.Empty, error) {
+	return &empty.Empty{}, nil
+}
+
+// UpdateImageDownload implements mock UpdateImageDownload
+func (mcs MockCoreService) UpdateImageDownload(ctx context.Context, in *voltha.ImageDownload, opts ...grpc.CallOption) (*empty.Empty, error) {
+	return &empty.Empty{}, nil
+}