[VOL-2193] Create mocks for Kafka Client and Etcd

This commit consists of:
1) A kafka client mock that implements the kafka client interface
under voltha-lib-go/pkg/kafka/client.go
2) An embedded Etcd server that runs in-process and represents an
Etcd server.

Change-Id: I52a36132568e08c596bb4136918bebcb654a3b99
diff --git a/vendor/go.etcd.io/etcd/lease/leasepb/lease.pb.go b/vendor/go.etcd.io/etcd/lease/leasepb/lease.pb.go
new file mode 100644
index 0000000..16637ee
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/lease/leasepb/lease.pb.go
@@ -0,0 +1,620 @@
+// Code generated by protoc-gen-gogo. DO NOT EDIT.
+// source: lease.proto
+
+/*
+	Package leasepb is a generated protocol buffer package.
+
+	It is generated from these files:
+		lease.proto
+
+	It has these top-level messages:
+		Lease
+		LeaseInternalRequest
+		LeaseInternalResponse
+*/
+package leasepb
+
+import (
+	"fmt"
+
+	proto "github.com/golang/protobuf/proto"
+
+	math "math"
+
+	_ "github.com/gogo/protobuf/gogoproto"
+
+	etcdserverpb "go.etcd.io/etcd/etcdserver/etcdserverpb"
+
+	io "io"
+)
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion2 // please upgrade the proto package
+
+type Lease struct {
+	ID           int64 `protobuf:"varint,1,opt,name=ID,proto3" json:"ID,omitempty"`
+	TTL          int64 `protobuf:"varint,2,opt,name=TTL,proto3" json:"TTL,omitempty"`
+	RemainingTTL int64 `protobuf:"varint,3,opt,name=RemainingTTL,proto3" json:"RemainingTTL,omitempty"`
+}
+
+func (m *Lease) Reset()                    { *m = Lease{} }
+func (m *Lease) String() string            { return proto.CompactTextString(m) }
+func (*Lease) ProtoMessage()               {}
+func (*Lease) Descriptor() ([]byte, []int) { return fileDescriptorLease, []int{0} }
+
+type LeaseInternalRequest struct {
+	LeaseTimeToLiveRequest *etcdserverpb.LeaseTimeToLiveRequest `protobuf:"bytes,1,opt,name=LeaseTimeToLiveRequest" json:"LeaseTimeToLiveRequest,omitempty"`
+}
+
+func (m *LeaseInternalRequest) Reset()                    { *m = LeaseInternalRequest{} }
+func (m *LeaseInternalRequest) String() string            { return proto.CompactTextString(m) }
+func (*LeaseInternalRequest) ProtoMessage()               {}
+func (*LeaseInternalRequest) Descriptor() ([]byte, []int) { return fileDescriptorLease, []int{1} }
+
+type LeaseInternalResponse struct {
+	LeaseTimeToLiveResponse *etcdserverpb.LeaseTimeToLiveResponse `protobuf:"bytes,1,opt,name=LeaseTimeToLiveResponse" json:"LeaseTimeToLiveResponse,omitempty"`
+}
+
+func (m *LeaseInternalResponse) Reset()                    { *m = LeaseInternalResponse{} }
+func (m *LeaseInternalResponse) String() string            { return proto.CompactTextString(m) }
+func (*LeaseInternalResponse) ProtoMessage()               {}
+func (*LeaseInternalResponse) Descriptor() ([]byte, []int) { return fileDescriptorLease, []int{2} }
+
+func init() {
+	proto.RegisterType((*Lease)(nil), "leasepb.Lease")
+	proto.RegisterType((*LeaseInternalRequest)(nil), "leasepb.LeaseInternalRequest")
+	proto.RegisterType((*LeaseInternalResponse)(nil), "leasepb.LeaseInternalResponse")
+}
+func (m *Lease) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalTo(dAtA)
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *Lease) MarshalTo(dAtA []byte) (int, error) {
+	var i int
+	_ = i
+	var l int
+	_ = l
+	if m.ID != 0 {
+		dAtA[i] = 0x8
+		i++
+		i = encodeVarintLease(dAtA, i, uint64(m.ID))
+	}
+	if m.TTL != 0 {
+		dAtA[i] = 0x10
+		i++
+		i = encodeVarintLease(dAtA, i, uint64(m.TTL))
+	}
+	if m.RemainingTTL != 0 {
+		dAtA[i] = 0x18
+		i++
+		i = encodeVarintLease(dAtA, i, uint64(m.RemainingTTL))
+	}
+	return i, nil
+}
+
+func (m *LeaseInternalRequest) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalTo(dAtA)
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *LeaseInternalRequest) MarshalTo(dAtA []byte) (int, error) {
+	var i int
+	_ = i
+	var l int
+	_ = l
+	if m.LeaseTimeToLiveRequest != nil {
+		dAtA[i] = 0xa
+		i++
+		i = encodeVarintLease(dAtA, i, uint64(m.LeaseTimeToLiveRequest.Size()))
+		n1, err := m.LeaseTimeToLiveRequest.MarshalTo(dAtA[i:])
+		if err != nil {
+			return 0, err
+		}
+		i += n1
+	}
+	return i, nil
+}
+
+func (m *LeaseInternalResponse) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalTo(dAtA)
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *LeaseInternalResponse) MarshalTo(dAtA []byte) (int, error) {
+	var i int
+	_ = i
+	var l int
+	_ = l
+	if m.LeaseTimeToLiveResponse != nil {
+		dAtA[i] = 0xa
+		i++
+		i = encodeVarintLease(dAtA, i, uint64(m.LeaseTimeToLiveResponse.Size()))
+		n2, err := m.LeaseTimeToLiveResponse.MarshalTo(dAtA[i:])
+		if err != nil {
+			return 0, err
+		}
+		i += n2
+	}
+	return i, nil
+}
+
+func encodeVarintLease(dAtA []byte, offset int, v uint64) int {
+	for v >= 1<<7 {
+		dAtA[offset] = uint8(v&0x7f | 0x80)
+		v >>= 7
+		offset++
+	}
+	dAtA[offset] = uint8(v)
+	return offset + 1
+}
+func (m *Lease) Size() (n int) {
+	var l int
+	_ = l
+	if m.ID != 0 {
+		n += 1 + sovLease(uint64(m.ID))
+	}
+	if m.TTL != 0 {
+		n += 1 + sovLease(uint64(m.TTL))
+	}
+	if m.RemainingTTL != 0 {
+		n += 1 + sovLease(uint64(m.RemainingTTL))
+	}
+	return n
+}
+
+func (m *LeaseInternalRequest) Size() (n int) {
+	var l int
+	_ = l
+	if m.LeaseTimeToLiveRequest != nil {
+		l = m.LeaseTimeToLiveRequest.Size()
+		n += 1 + l + sovLease(uint64(l))
+	}
+	return n
+}
+
+func (m *LeaseInternalResponse) Size() (n int) {
+	var l int
+	_ = l
+	if m.LeaseTimeToLiveResponse != nil {
+		l = m.LeaseTimeToLiveResponse.Size()
+		n += 1 + l + sovLease(uint64(l))
+	}
+	return n
+}
+
+func sovLease(x uint64) (n int) {
+	for {
+		n++
+		x >>= 7
+		if x == 0 {
+			break
+		}
+	}
+	return n
+}
+func sozLease(x uint64) (n int) {
+	return sovLease(uint64((x << 1) ^ uint64((int64(x) >> 63))))
+}
+func (m *Lease) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowLease
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: Lease: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: Lease: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field ID", wireType)
+			}
+			m.ID = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowLease
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.ID |= (int64(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		case 2:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field TTL", wireType)
+			}
+			m.TTL = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowLease
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.TTL |= (int64(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		case 3:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field RemainingTTL", wireType)
+			}
+			m.RemainingTTL = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowLease
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.RemainingTTL |= (int64(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		default:
+			iNdEx = preIndex
+			skippy, err := skipLease(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if skippy < 0 {
+				return ErrInvalidLengthLease
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *LeaseInternalRequest) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowLease
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: LeaseInternalRequest: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: LeaseInternalRequest: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field LeaseTimeToLiveRequest", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowLease
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= (int(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthLease
+			}
+			postIndex := iNdEx + msglen
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.LeaseTimeToLiveRequest == nil {
+				m.LeaseTimeToLiveRequest = &etcdserverpb.LeaseTimeToLiveRequest{}
+			}
+			if err := m.LeaseTimeToLiveRequest.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipLease(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if skippy < 0 {
+				return ErrInvalidLengthLease
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *LeaseInternalResponse) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowLease
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: LeaseInternalResponse: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: LeaseInternalResponse: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field LeaseTimeToLiveResponse", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowLease
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= (int(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthLease
+			}
+			postIndex := iNdEx + msglen
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.LeaseTimeToLiveResponse == nil {
+				m.LeaseTimeToLiveResponse = &etcdserverpb.LeaseTimeToLiveResponse{}
+			}
+			if err := m.LeaseTimeToLiveResponse.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipLease(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if skippy < 0 {
+				return ErrInvalidLengthLease
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func skipLease(dAtA []byte) (n int, err error) {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return 0, ErrIntOverflowLease
+			}
+			if iNdEx >= l {
+				return 0, io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		wireType := int(wire & 0x7)
+		switch wireType {
+		case 0:
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowLease
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				iNdEx++
+				if dAtA[iNdEx-1] < 0x80 {
+					break
+				}
+			}
+			return iNdEx, nil
+		case 1:
+			iNdEx += 8
+			return iNdEx, nil
+		case 2:
+			var length int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowLease
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				length |= (int(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			iNdEx += length
+			if length < 0 {
+				return 0, ErrInvalidLengthLease
+			}
+			return iNdEx, nil
+		case 3:
+			for {
+				var innerWire uint64
+				var start int = iNdEx
+				for shift := uint(0); ; shift += 7 {
+					if shift >= 64 {
+						return 0, ErrIntOverflowLease
+					}
+					if iNdEx >= l {
+						return 0, io.ErrUnexpectedEOF
+					}
+					b := dAtA[iNdEx]
+					iNdEx++
+					innerWire |= (uint64(b) & 0x7F) << shift
+					if b < 0x80 {
+						break
+					}
+				}
+				innerWireType := int(innerWire & 0x7)
+				if innerWireType == 4 {
+					break
+				}
+				next, err := skipLease(dAtA[start:])
+				if err != nil {
+					return 0, err
+				}
+				iNdEx = start + next
+			}
+			return iNdEx, nil
+		case 4:
+			return iNdEx, nil
+		case 5:
+			iNdEx += 4
+			return iNdEx, nil
+		default:
+			return 0, fmt.Errorf("proto: illegal wireType %d", wireType)
+		}
+	}
+	panic("unreachable")
+}
+
+var (
+	ErrInvalidLengthLease = fmt.Errorf("proto: negative length found during unmarshaling")
+	ErrIntOverflowLease   = fmt.Errorf("proto: integer overflow")
+)
+
+func init() { proto.RegisterFile("lease.proto", fileDescriptorLease) }
+
+var fileDescriptorLease = []byte{
+	// 253 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xe2, 0xe2, 0xce, 0x49, 0x4d, 0x2c,
+	0x4e, 0xd5, 0x2b, 0x28, 0xca, 0x2f, 0xc9, 0x17, 0x62, 0x07, 0x73, 0x0a, 0x92, 0xa4, 0x44, 0xd2,
+	0xf3, 0xd3, 0xf3, 0xc1, 0x62, 0xfa, 0x20, 0x16, 0x44, 0x5a, 0x4a, 0x2d, 0xb5, 0x24, 0x39, 0x45,
+	0x1f, 0x44, 0x14, 0xa7, 0x16, 0x95, 0xa5, 0x16, 0x21, 0x31, 0x0b, 0x92, 0xf4, 0x8b, 0x0a, 0x92,
+	0x21, 0xea, 0x94, 0x7c, 0xb9, 0x58, 0x7d, 0x40, 0x06, 0x09, 0xf1, 0x71, 0x31, 0x79, 0xba, 0x48,
+	0x30, 0x2a, 0x30, 0x6a, 0x30, 0x07, 0x31, 0x79, 0xba, 0x08, 0x09, 0x70, 0x31, 0x87, 0x84, 0xf8,
+	0x48, 0x30, 0x81, 0x05, 0x40, 0x4c, 0x21, 0x25, 0x2e, 0x9e, 0xa0, 0xd4, 0xdc, 0xc4, 0xcc, 0xbc,
+	0xcc, 0xbc, 0x74, 0x90, 0x14, 0x33, 0x58, 0x0a, 0x45, 0x4c, 0xa9, 0x84, 0x4b, 0x04, 0x6c, 0x9c,
+	0x67, 0x5e, 0x49, 0x6a, 0x51, 0x5e, 0x62, 0x4e, 0x50, 0x6a, 0x61, 0x69, 0x6a, 0x71, 0x89, 0x50,
+	0x0c, 0x97, 0x18, 0x58, 0x3c, 0x24, 0x33, 0x37, 0x35, 0x24, 0xdf, 0x27, 0xb3, 0x2c, 0x15, 0x2a,
+	0x03, 0xb6, 0x91, 0xdb, 0x48, 0x45, 0x0f, 0xd9, 0x7d, 0x7a, 0xd8, 0xd5, 0x06, 0xe1, 0x30, 0x43,
+	0xa9, 0x82, 0x4b, 0x14, 0xcd, 0xd6, 0xe2, 0x82, 0xfc, 0xbc, 0xe2, 0x54, 0xa1, 0x78, 0x2e, 0x71,
+	0x0c, 0x2d, 0x10, 0x29, 0xa8, 0xbd, 0xaa, 0x04, 0xec, 0x85, 0x28, 0x0e, 0xc2, 0x65, 0x8a, 0x93,
+	0xc4, 0x89, 0x87, 0x72, 0x0c, 0x17, 0x1e, 0xca, 0x31, 0x9c, 0x78, 0x24, 0xc7, 0x78, 0xe1, 0x91,
+	0x1c, 0xe3, 0x83, 0x47, 0x72, 0x8c, 0x33, 0x1e, 0xcb, 0x31, 0x24, 0xb1, 0x81, 0xc3, 0xd7, 0x18,
+	0x10, 0x00, 0x00, 0xff, 0xff, 0xa9, 0x9f, 0x8b, 0x6c, 0xb5, 0x01, 0x00, 0x00,
+}