diff --git a/src/app/service/user/user.service_test.go b/src/app/service/user/user.service_test.go
new file mode 100644
index 0000000..8f9103c
--- /dev/null
+++ b/src/app/service/user/user.service_test.go
@@ -0,0 +1,278 @@
+package user
+
+import (
+	"net/http"
+	"testing"
+
+	"github.com/go-faker/faker/v4"
+	"github.com/isd-sgcu/johnjud-gateway/src/app/constant"
+	"github.com/isd-sgcu/johnjud-gateway/src/app/dto"
+	"github.com/isd-sgcu/johnjud-gateway/src/mocks/client/user"
+	proto "github.com/isd-sgcu/johnjud-go-proto/johnjud/auth/user/v1"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/suite"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+type UserServiceTest struct {
+	suite.Suite
+	User                  *proto.User
+	FindOneUserReq        *proto.FindOneUserRequest
+	UpdateUserReq         *proto.UpdateUserRequest
+	UpdateUserDto         *dto.UpdateUserRequest
+	DeleteUserReq         *proto.DeleteUserRequest
+	NotFoundErr           *dto.ResponseErr
+	UnavailableServiceErr *dto.ResponseErr
+	ConflictErr           *dto.ResponseErr
+	InternalErr           *dto.ResponseErr
+}
+
+func TestUserService(t *testing.T) {
+	suite.Run(t, new(UserServiceTest))
+}
+
+func (t *UserServiceTest) SetupTest() {
+	t.User = &proto.User{
+		Id:        faker.UUIDDigit(),
+		Email:     faker.Email(),
+		Password:  faker.Password(),
+		Firstname: faker.FirstName(),
+		Lastname:  faker.LastName(),
+		Role:      "user",
+	}
+
+	t.FindOneUserReq = &proto.FindOneUserRequest{
+		Id: t.User.Id,
+	}
+
+	t.UpdateUserDto = &dto.UpdateUserRequest{
+		Email:     faker.Email(),
+		Password:  faker.Password(),
+		Firstname: faker.FirstName(),
+		Lastname:  faker.LastName(),
+	}
+
+	t.UpdateUserReq = &proto.UpdateUserRequest{
+		Id:        t.User.Id,
+		Email:     t.UpdateUserDto.Email,
+		Password:  t.UpdateUserDto.Password,
+		Firstname: t.UpdateUserDto.Firstname,
+		Lastname:  t.UpdateUserDto.Lastname,
+	}
+
+	t.DeleteUserReq = &proto.DeleteUserRequest{
+		Id: t.User.Id,
+	}
+
+	t.UnavailableServiceErr = &dto.ResponseErr{
+		StatusCode: http.StatusServiceUnavailable,
+		Message:    constant.UnavailableServiceMessage,
+		Data:       nil,
+	}
+
+	t.NotFoundErr = &dto.ResponseErr{
+		StatusCode: http.StatusNotFound,
+		Message:    constant.UserNotFoundMessage,
+		Data:       nil,
+	}
+
+	t.ConflictErr = &dto.ResponseErr{
+		StatusCode: http.StatusConflict,
+		Message:    constant.DuplicateEmailMessage,
+		Data:       nil,
+	}
+
+	t.InternalErr = &dto.ResponseErr{
+		StatusCode: http.StatusInternalServerError,
+		Message:    constant.InternalErrorMessage,
+		Data:       nil,
+	}
+}
+
+func (t *UserServiceTest) TestFindOneSuccess() {
+	protoResp := &proto.FindOneUserResponse{
+		User: &proto.User{
+			Id:        t.User.Id,
+			Email:     t.User.Email,
+			Firstname: t.User.Firstname,
+			Lastname:  t.User.Lastname,
+			Role:      t.User.Role,
+		},
+	}
+
+	expected := &dto.FindOneUserResponse{
+		Id:        t.User.Id,
+		Email:     t.User.Email,
+		Firstname: t.User.Firstname,
+		Lastname:  t.User.Lastname,
+	}
+
+	client := user.UserClientMock{}
+	client.On("FindOne", t.FindOneUserReq).Return(protoResp, nil)
+
+	svc := NewService(&client)
+	actual, err := svc.FindOne(t.User.Id)
+
+	assert.Nil(t.T(), err)
+	assert.Equal(t.T(), expected, actual)
+}
+
+func (t *UserServiceTest) TestFindOneNotFoundError() {
+	expected := t.NotFoundErr
+
+	client := user.UserClientMock{}
+	clienErr := status.Error(codes.NotFound, constant.UserNotFoundMessage)
+	client.On("FindOne", t.FindOneUserReq).Return(nil, clienErr)
+
+	svc := NewService(&client)
+	actual, err := svc.FindOne(t.User.Id)
+
+	assert.Nil(t.T(), actual)
+	assert.Equal(t.T(), expected, err)
+}
+
+func (t *UserServiceTest) TestFindOneUnavailableServiceError() {
+	expected := t.UnavailableServiceErr
+
+	client := user.UserClientMock{}
+	clientErr := status.Error(codes.Unavailable, constant.UnavailableServiceMessage)
+	client.On("FindOne", t.FindOneUserReq).Return(nil, clientErr)
+
+	svc := NewService(&client)
+	actual, err := svc.FindOne(t.User.Id)
+
+	assert.Nil(t.T(), actual)
+	assert.Equal(t.T(), expected, err)
+}
+
+func (t *UserServiceTest) TestFindOneInternalError() {
+	expected := t.InternalErr
+
+	client := user.UserClientMock{}
+	clientErr := status.Error(codes.Internal, constant.InternalErrorMessage)
+	client.On("FindOne", t.FindOneUserReq).Return(nil, clientErr)
+
+	svc := NewService(&client)
+	actual, err := svc.FindOne(t.User.Id)
+
+	assert.Nil(t.T(), actual)
+	assert.Equal(t.T(), expected, err)
+}
+
+func (t *UserServiceTest) TestUpdateSuccess() {
+	protoResp := &proto.UpdateUserResponse{
+		User: &proto.User{
+			Id:        t.User.Id,
+			Email:     t.User.Email,
+			Firstname: t.User.Firstname,
+			Lastname:  t.User.Lastname,
+			Role:      t.User.Role,
+		},
+	}
+
+	expected := &dto.UpdateUserResponse{
+		Id:        t.User.Id,
+		Email:     t.User.Email,
+		Firstname: t.User.Firstname,
+		Lastname:  t.User.Lastname,
+	}
+
+	client := user.UserClientMock{}
+	client.On("Update", t.UpdateUserReq).Return(protoResp, nil)
+
+	svc := NewService(&client)
+	actual, err := svc.Update(t.User.Id, t.UpdateUserDto)
+
+	assert.Nil(t.T(), err)
+	assert.Equal(t.T(), expected, actual)
+}
+
+func (t *UserServiceTest) TestUpdateDuplicateEmail() {
+	expected := t.ConflictErr
+
+	client := user.UserClientMock{}
+	clientErr := status.Error(codes.AlreadyExists, constant.DuplicateEmailMessage)
+	client.On("Update", t.UpdateUserReq).Return(nil, clientErr)
+
+	svc := NewService(&client)
+	actual, err := svc.Update(t.User.Id, t.UpdateUserDto)
+
+	assert.Nil(t.T(), actual)
+	assert.Equal(t.T(), expected, err)
+}
+
+func (t *UserServiceTest) TestUpdateUnavailableServiceError() {
+	expected := t.UnavailableServiceErr
+
+	client := user.UserClientMock{}
+	clientErr := status.Error(codes.Unavailable, constant.UnavailableServiceMessage)
+	client.On("Update", t.UpdateUserReq).Return(nil, clientErr)
+
+	svc := NewService(&client)
+	actual, err := svc.Update(t.User.Id, t.UpdateUserDto)
+
+	assert.Nil(t.T(), actual)
+	assert.Equal(t.T(), expected, err)
+}
+
+func (t *UserServiceTest) TestUpdateInternalError() {
+	expected := t.InternalErr
+
+	client := user.UserClientMock{}
+	clientErr := status.Error(codes.Internal, constant.InternalErrorMessage)
+	client.On("Update", t.UpdateUserReq).Return(nil, clientErr)
+
+	svc := NewService(&client)
+	actual, err := svc.Update(t.User.Id, t.UpdateUserDto)
+
+	assert.Nil(t.T(), actual)
+	assert.Equal(t.T(), expected, err)
+}
+
+func (t *UserServiceTest) TestDeleteSuccess() {
+	protoResp := &proto.DeleteUserResponse{
+		Success: true,
+	}
+
+	expected := &dto.DeleteUserResponse{
+		Success: true,
+	}
+
+	client := user.UserClientMock{}
+	client.On("Delete", t.DeleteUserReq).Return(protoResp, nil)
+
+	svc := NewService(&client)
+	actual, err := svc.Delete(t.User.Id)
+
+	assert.Nil(t.T(), err)
+	assert.Equal(t.T(), expected, actual)
+}
+
+func (t *UserServiceTest) TestDeleteUnavailableServiceError() {
+	expected := t.UnavailableServiceErr
+
+	client := user.UserClientMock{}
+	clientErr := status.Error(codes.Unavailable, constant.UnavailableServiceMessage)
+	client.On("Delete", t.DeleteUserReq).Return(nil, clientErr)
+
+	svc := NewService(&client)
+	actual, err := svc.Delete(t.User.Id)
+
+	assert.Nil(t.T(), actual)
+	assert.Equal(t.T(), expected, err)
+}
+
+func (t *UserServiceTest) TestDeleteInternalError() {
+	expected := t.InternalErr
+
+	client := user.UserClientMock{}
+	clientErr := status.Error(codes.Internal, constant.InternalErrorMessage)
+	client.On("Delete", t.DeleteUserReq).Return(nil, clientErr)
+
+	svc := NewService(&client)
+	actual, err := svc.Delete(t.User.Id)
+
+	assert.Nil(t.T(), actual)
+	assert.Equal(t.T(), expected, err)
+}