diff --git a/src/authentication/authentication.module.ts b/src/authentication/authentication.module.ts
index e080d73..3deb67b 100644
--- a/src/authentication/authentication.module.ts
+++ b/src/authentication/authentication.module.ts
@@ -75,7 +75,7 @@ const providers: Provider[] = [
     TwilioImplModule,
     HttpModule,
   ],
-  providers: providers,
+  providers,
   controllers: [GoogleAuthController],
 })
 export class UserAuthModule {}
diff --git a/src/authentication/service/google.service.ts b/src/authentication/service/google.service.ts
index 7f195f6..bf0e978 100644
--- a/src/authentication/service/google.service.ts
+++ b/src/authentication/service/google.service.ts
@@ -1,15 +1,15 @@
-import { Injectable } from '@nestjs/common';
+import { Inject, Injectable } from '@nestjs/common';
 import { InvalidPayloadException } from '../exception/userauth.exception';
 import User from '../../authorization/entity/user.entity';
 import { GoogleUserSchema } from '../validation/user.auth.schema.validation';
-import UserService from '../../authorization/service/user.service';
+import { UserServiceInterface } from '../../authorization/service/user.service.interface';
 import { AuthenticationHelper } from '../authentication.helper';
 import { GoogleLoginUser } from '../passport/googleStrategy';
 
 @Injectable()
 export class GoogleAuthService {
   constructor(
-    private userService: UserService,
+    @Inject(UserServiceInterface) private userService: UserServiceInterface,
     private authenticationHelper: AuthenticationHelper,
   ) {}
   private async validateInput(
diff --git a/src/authentication/service/otp.auth.service.ts b/src/authentication/service/otp.auth.service.ts
index e3d9462..5725f54 100644
--- a/src/authentication/service/otp.auth.service.ts
+++ b/src/authentication/service/otp.auth.service.ts
@@ -1,7 +1,7 @@
-import { Injectable } from '@nestjs/common';
+import { Inject, Injectable } from '@nestjs/common';
 import User from '../../authorization/entity/user.entity';
 import { UserNotFoundException } from '../../authorization/exception/user.exception';
-import UserService from '../../authorization/service/user.service';
+import { UserServiceInterface } from '../../authorization/service/user.service.interface';
 import {
   Status,
   TokenResponse,
@@ -20,7 +20,7 @@ import { TokenService } from './token.service';
 @Injectable()
 export default class OTPAuthService implements Authenticatable {
   constructor(
-    private userService: UserService,
+    @Inject(UserServiceInterface) private userService: UserServiceInterface,
     private tokenService: TokenService,
     private otpService: OTPVerifiable,
   ) {}
diff --git a/src/authentication/service/password.auth.service.ts b/src/authentication/service/password.auth.service.ts
index 09f7b64..6dd99da 100644
--- a/src/authentication/service/password.auth.service.ts
+++ b/src/authentication/service/password.auth.service.ts
@@ -1,4 +1,4 @@
-import { Injectable } from '@nestjs/common';
+import { Inject, Injectable } from '@nestjs/common';
 import { ConfigService } from '@nestjs/config';
 import { DataSource } from 'typeorm';
 import User from '../../authorization/entity/user.entity';
@@ -6,7 +6,7 @@ import {
   PasswordAlreadySetException,
   UserNotFoundException,
 } from '../../authorization/exception/user.exception';
-import UserService from '../../authorization/service/user.service';
+import { UserServiceInterface } from '../../authorization/service/user.service.interface';
 import {
   InviteTokenResponse,
   Status,
@@ -29,7 +29,7 @@ import { TokenService } from './token.service';
 @Injectable()
 export default class PasswordAuthService implements Authenticatable {
   constructor(
-    private userService: UserService,
+    @Inject(UserServiceInterface) private userService: UserServiceInterface,
     private tokenService: TokenService,
     private authenticationHelper: AuthenticationHelper,
     private dataSource: DataSource,
diff --git a/src/authentication/service/token.service.ts b/src/authentication/service/token.service.ts
index ada050f..d0826ec 100644
--- a/src/authentication/service/token.service.ts
+++ b/src/authentication/service/token.service.ts
@@ -1,11 +1,11 @@
-import { Injectable, UnauthorizedException } from '@nestjs/common';
+import { Inject, Injectable, UnauthorizedException } from '@nestjs/common';
 import { ConfigService } from '@nestjs/config';
 import User from '../../authorization/entity/user.entity';
 import {
   InviteTokenAlreadyRevokedException,
   PasswordAlreadySetException,
 } from '../../authorization/exception/user.exception';
-import UserService from '../../authorization/service/user.service';
+import { UserServiceInterface } from '../../authorization/service/user.service.interface';
 import {
   InviteTokenResponse,
   TokenResponse,
@@ -15,7 +15,7 @@ import { AuthenticationHelper } from '../authentication.helper';
 @Injectable()
 export class TokenService {
   constructor(
-    private userService: UserService,
+    @Inject(UserServiceInterface) private userService: UserServiceInterface,
     private authenticationHelper: AuthenticationHelper,
     private configService: ConfigService,
   ) {}
diff --git a/src/authorization/authorization.guard.ts b/src/authorization/authorization.guard.ts
index 454893c..4cd0f4d 100644
--- a/src/authorization/authorization.guard.ts
+++ b/src/authorization/authorization.guard.ts
@@ -1,11 +1,19 @@
-import { CanActivate, ExecutionContext, Injectable } from '@nestjs/common';
+import {
+  CanActivate,
+  ExecutionContext,
+  Inject,
+  Injectable,
+} from '@nestjs/common';
 import { Reflector } from '@nestjs/core';
 import { GqlExecutionContext } from '@nestjs/graphql';
-import UserService from './service/user.service';
+import { UserServiceInterface } from './service/user.service.interface';
 
 @Injectable()
 export class AuthorizationGaurd implements CanActivate {
-  constructor(private userService: UserService, private reflector: Reflector) {}
+  constructor(
+    @Inject(UserServiceInterface) private userService: UserServiceInterface,
+    private reflector: Reflector,
+  ) {}
   public async canActivate(context: ExecutionContext): Promise<boolean> {
     const ctx = GqlExecutionContext.create(context).getContext();
     const permissionsRequired = this.reflector.get<string[]>(
diff --git a/src/authorization/authorization.module.ts b/src/authorization/authorization.module.ts
index 6c15c58..b6cc2c7 100644
--- a/src/authorization/authorization.module.ts
+++ b/src/authorization/authorization.module.ts
@@ -46,8 +46,10 @@ import { RoleServiceInterface } from './service/role.service.interface';
 import RoleCacheService from './service/rolecache.service';
 import { RoleCacheServiceInterface } from './service/rolecache.service.interface';
 import SearchService from './service/search.service';
-import UserService from './service/user.service';
-import UserCacheService from './service/usercache.service';
+import { UserService } from './service/user.service';
+import { UserServiceInterface } from './service/user.service.interface';
+import { UserCacheService } from './service/usercache.service';
+import { UserCacheServiceInterface } from './service/usercache.service.interface';
 
 @Module({
   imports: [
@@ -69,11 +71,9 @@ import UserCacheService from './service/usercache.service';
   providers: [
     GroupResolver,
     PermissionResolver,
-    UserService,
     UserResolver,
     EntityResolver,
     RedisCacheService,
-    UserCacheService,
     AuthenticationHelper,
     ConfigService,
     RoleResolver,
@@ -117,7 +117,20 @@ import UserCacheService from './service/usercache.service';
       provide: GroupCacheServiceInterface,
       useClass: GroupCacheService,
     },
+    {
+      provide: UserServiceInterface,
+      useClass: UserService,
+    },
+    {
+      provide: UserCacheServiceInterface,
+      useClass: UserCacheService,
+    },
+  ],
+  exports: [
+    {
+      provide: UserServiceInterface,
+      useClass: UserService,
+    },
   ],
-  exports: [UserService],
 })
 export class AuthorizationModule {}
diff --git a/src/authorization/resolver/user.resolver.ts b/src/authorization/resolver/user.resolver.ts
index 7a575dd..820561b 100644
--- a/src/authorization/resolver/user.resolver.ts
+++ b/src/authorization/resolver/user.resolver.ts
@@ -1,4 +1,4 @@
-import { UseGuards } from '@nestjs/common';
+import { Inject, UseGuards } from '@nestjs/common';
 import { ParseUUIDPipe } from '@nestjs/common/pipes';
 import {
   Args,
@@ -24,12 +24,14 @@ import {
 import ValidationPipe from '../../validation/validation.pipe';
 import { PermissionsType } from '../constants/authorization.constants';
 import { Permissions } from '../permissions.decorator';
-import UserService from '../service/user.service';
+import { UserServiceInterface } from '../service/user.service.interface';
 import * as UserSchema from '../validation/user.validation.schema';
 
 @Resolver('User')
 export class UserResolver {
-  constructor(private userService: UserService) {}
+  constructor(
+    @Inject(UserServiceInterface) private userService: UserServiceInterface,
+  ) {}
 
   @Permissions(PermissionsType.ViewUser)
   @Query()
diff --git a/src/authorization/service/group.service.ts b/src/authorization/service/group.service.ts
index 1122a6d..9359538 100644
--- a/src/authorization/service/group.service.ts
+++ b/src/authorization/service/group.service.ts
@@ -32,7 +32,7 @@ import { UserGroupRepository } from '../repository/userGroup.repository';
 import { GroupServiceInterface } from './group.service.interface';
 import { GroupCacheServiceInterface } from './groupcache.service.interface';
 import SearchService from './search.service';
-import UserCacheService from './usercache.service';
+import { UserCacheServiceInterface } from './usercache.service.interface';
 
 @Injectable()
 export class GroupService implements GroupServiceInterface {
@@ -47,7 +47,8 @@ export class GroupService implements GroupServiceInterface {
     private dataSource: DataSource,
     @Inject(GroupCacheServiceInterface)
     private groupCacheService: GroupCacheServiceInterface,
-    private userCacheService: UserCacheService,
+    @Inject(UserCacheServiceInterface)
+    private userCacheService: UserCacheServiceInterface,
     private searchService: SearchService,
   ) {}
 
diff --git a/src/authorization/service/user.service.interface.ts b/src/authorization/service/user.service.interface.ts
new file mode 100644
index 0000000..cf1da42
--- /dev/null
+++ b/src/authorization/service/user.service.interface.ts
@@ -0,0 +1,66 @@
+import User from '../entity/user.entity';
+import {
+  OperationType,
+  UpdateUserGroupInput,
+  UpdateUserInput,
+  UpdateUserPermissionInput,
+  UserInputFilter,
+} from '../../schema/graphql.schema';
+import Group from '../entity/group.entity';
+import Permission from '../entity/permission.entity';
+
+export interface UserServiceInterface {
+  getAllUsers(input?: UserInputFilter): Promise<[User[], number]>;
+
+  getUserById(id: string): Promise<User>;
+
+  createUser(user: User): Promise<User>;
+
+  updateUser(id: string, user: UpdateUserInput): Promise<User>;
+
+  updateUserGroups(id: string, user: UpdateUserGroupInput): Promise<Group[]>;
+
+  getUserGroups(id: string): Promise<Group[]>;
+
+  updateUserPermissions(
+    id: string,
+    request: UpdateUserPermissionInput,
+  ): Promise<Permission[]>;
+
+  getUserPermissions(id: string): Promise<Permission[]>;
+
+  deleteUser(id: string): Promise<User>;
+
+  getAllUserpermissionIds(id: string): Promise<Set<string>>;
+
+  permissionsOfUser(id: string): Promise<Permission[]>;
+
+  verifyUserPermissions(
+    id: string,
+    permissionsToVerify: string[],
+    operation?: OperationType,
+  ): Promise<boolean>;
+
+  verifyDuplicateUser(
+    email?: string | undefined,
+    phone?: string | undefined,
+  ): Promise<{ existingUserDetails?: User | null; duplicate: string }>;
+
+  getUserDetailsByEmailOrPhone(
+    email?: string | undefined,
+    phone?: string | undefined,
+  ): Promise<any>;
+
+  getUserDetailsByUsername(
+    email?: string | undefined,
+    phone?: string | undefined,
+  ): Promise<User | null>;
+
+  updateField(id: string, field: string, value: any): Promise<User>;
+
+  getActiveUserByPhoneNumber(phone: string): Promise<User | null>;
+
+  setOtpSecret(user: User, twoFASecret: string): Promise<void>;
+}
+
+export const UserServiceInterface = Symbol('UserServiceInterface');
diff --git a/src/authorization/service/user.service.ts b/src/authorization/service/user.service.ts
index c4ab014..4aa563b 100644
--- a/src/authorization/service/user.service.ts
+++ b/src/authorization/service/user.service.ts
@@ -29,17 +29,19 @@ import { GroupCacheServiceInterface } from './groupcache.service.interface';
 import { PermissionCacheServiceInterface } from './permissioncache.service.interface';
 import { RoleCacheServiceInterface } from './rolecache.service.interface';
 import SearchService from './search.service';
-import UserCacheService from './usercache.service';
+import { UserServiceInterface } from './user.service.interface';
+import { UserCacheServiceInterface } from './usercache.service.interface';
 
 @Injectable()
-export default class UserService {
+export class UserService implements UserServiceInterface {
   constructor(
     private userRepository: UserRepository,
     private userGroupRepository: UserGroupRepository,
     private groupRepository: GroupRepository,
     private userPermissionRepository: UserPermissionRepository,
     private permissionRepository: PermissionRepository,
-    private userCacheService: UserCacheService,
+    @Inject(UserCacheServiceInterface)
+    private userCacheService: UserCacheServiceInterface,
     @Inject(GroupCacheServiceInterface)
     private groupCacheService: GroupCacheServiceInterface,
     @Inject(PermissionCacheServiceInterface)
@@ -263,7 +265,7 @@ export default class UserService {
     return allPermissionsOfUser;
   }
 
-  public async permissionsOfUser(id: string) {
+  public async permissionsOfUser(id: string): Promise<Permission[]> {
     const setOfPermissions: Set<string> = await this.getAllUserpermissionIds(
       id,
     );
diff --git a/src/authorization/service/usercache.service.interface.ts b/src/authorization/service/usercache.service.interface.ts
new file mode 100644
index 0000000..4510565
--- /dev/null
+++ b/src/authorization/service/usercache.service.interface.ts
@@ -0,0 +1,11 @@
+export interface UserCacheServiceInterface {
+  getUserGroupsByUserId(userId: string): Promise<string[]>;
+
+  getUserPermissionsByUserId(userId: string): Promise<string[]>;
+
+  invalidateUserPermissionsCache(userId: string): Promise<void>;
+
+  invalidateUserGroupsCache(userId: string): Promise<void>;
+}
+
+export const UserCacheServiceInterface = Symbol('UserCacheServiceInterface');
diff --git a/src/authorization/service/usercache.service.ts b/src/authorization/service/usercache.service.ts
index cc59aae..7ee5f6f 100644
--- a/src/authorization/service/usercache.service.ts
+++ b/src/authorization/service/usercache.service.ts
@@ -3,9 +3,10 @@ import { RedisCacheService } from '../../cache/redis-cache/redis-cache.service';
 import { UserRepository } from '../repository/user.repository';
 import { UserGroupRepository } from '../repository/userGroup.repository';
 import { UserPermissionRepository } from '../repository/userPermission.repository';
+import { UserCacheServiceInterface } from './usercache.service.interface';
 
 @Injectable()
-export default class UserCacheService {
+export class UserCacheService implements UserCacheServiceInterface {
   constructor(
     private cacheManager: RedisCacheService,
     private userGroupRepository: UserGroupRepository,
diff --git a/test/authentication/resolver/userauth.resolver.test.ts b/test/authentication/resolver/userauth.resolver.test.ts
index 938bc7a..cf71957 100644
--- a/test/authentication/resolver/userauth.resolver.test.ts
+++ b/test/authentication/resolver/userauth.resolver.test.ts
@@ -1,7 +1,8 @@
 import { Test, TestingModule } from '@nestjs/testing';
+import { ConfigService } from '@nestjs/config';
 import * as request from 'supertest';
 import { INestApplication } from '@nestjs/common';
-import UserService from '../../../src/authorization/service/user.service';
+import { UserServiceInterface } from '../../../src/authorization/service/user.service.interface';
 import Substitute, { Arg } from '@fluffy-spoon/substitute';
 import User from '../../../src/authorization/entity/user.entity';
 import { UserResolver } from '../../../src/authorization/resolver/user.resolver';
@@ -18,12 +19,11 @@ import {
 } from '../../../src/schema/graphql.schema';
 import UserAuthResolver from '../../../src/authentication/resolver/user.auth.resolver';
 import { AuthenticationHelper } from '../../../src/authentication/authentication.helper';
-import { ConfigService } from '@nestjs/config';
-import UserCacheService from '../../../src/authorization/service/usercache.service';
 import { RedisCacheService } from '../../../src/cache/redis-cache/redis-cache.service';
 import PasswordAuthService from '../../../src/authentication/service/password.auth.service';
 import OTPAuthService from '../../../src/authentication/service/otp.auth.service';
 import { TokenService } from '../../../src/authentication/service/token.service';
+import { UserCacheServiceInterface } from '../../../src/authorization/service/usercache.service.interface';
 
 const users: User[] = [
   {
@@ -40,11 +40,11 @@ const users: User[] = [
 
 const gql = '/graphql';
 
-const userService = Substitute.for<UserService>();
+const userService = Substitute.for<UserServiceInterface>();
 const passwordAuthService = Substitute.for<PasswordAuthService>();
 const otpAuthService = Substitute.for<OTPAuthService>();
 const tokenService = Substitute.for<TokenService>();
-const userCacheService = Substitute.for<UserCacheService>();
+const userCacheService = Substitute.for<UserCacheServiceInterface>();
 const redisCacheService = Substitute.for<RedisCacheService>();
 
 describe('Userauth Module', () => {
@@ -60,13 +60,13 @@ describe('Userauth Module', () => {
         UserAuthResolver,
         ConfigService,
         AuthenticationHelper,
-        { provide: 'UserService', useValue: userService },
-        { provide: 'TokenService', useValue: tokenService },
-        { provide: 'PasswordAuthService', useValue: passwordAuthService },
-        { provide: 'OTPAuthService', useValue: otpAuthService },
-        { provide: 'ConfigService', useValue: configService },
-        { provide: 'UserCacheService', useValue: userCacheService },
-        { provide: 'RedisCacheService', useValue: redisCacheService },
+        { provide: UserServiceInterface, useValue: userService },
+        { provide: TokenService, useValue: tokenService },
+        { provide: PasswordAuthService, useValue: passwordAuthService },
+        { provide: OTPAuthService, useValue: otpAuthService },
+        { provide: ConfigService, useValue: configService },
+        { provide: UserCacheServiceInterface, useValue: userCacheService },
+        { provide: RedisCacheService, useValue: redisCacheService },
       ],
     }).compile();
     authenticationHelper = moduleFixture.get<AuthenticationHelper>(
diff --git a/test/authentication/service/otpauth.service.test.ts b/test/authentication/service/otpauth.service.test.ts
index aa700aa..97f66c2 100644
--- a/test/authentication/service/otpauth.service.test.ts
+++ b/test/authentication/service/otpauth.service.test.ts
@@ -10,7 +10,7 @@ import OTPAuthService from '../../../src/authentication/service/otp.auth.service
 import { TokenService } from '../../../src/authentication/service/token.service';
 import TwilioOTPService from '../../../src/authentication/service/twilio.otp.service';
 import User from '../../../src/authorization/entity/user.entity';
-import UserService from '../../../src/authorization/service/user.service';
+import { UserServiceInterface } from '../../../src/authorization/service/user.service.interface';
 import {
   Status,
   TokenResponse,
@@ -34,7 +34,7 @@ let users: User[] = [
 describe('test OTPAuthService', () => {
   let otpAuthService: OTPAuthService;
   let authenticationHelper: AuthenticationHelper;
-  const userService = Substitute.for<UserService>();
+  const userService = Substitute.for<UserServiceInterface>();
   const configService = Substitute.for<ConfigService>();
   const otpService = Substitute.for<TwilioOTPService>();
   const tokenService = Substitute.for<TokenService>();
@@ -46,9 +46,9 @@ describe('test OTPAuthService', () => {
       imports: [ConfigModule],
       controllers: [],
       providers: [
-        { provide: 'UserService', useValue: userService },
-        { provide: 'ConfigService', useValue: configService },
-        { provide: 'TokenService', useValue: tokenService },
+        { provide: UserServiceInterface, useValue: userService },
+        { provide: ConfigService, useValue: configService },
+        { provide: TokenService, useValue: tokenService },
         { provide: 'OTPVerifiable', useValue: otpService },
         OTPAuthService,
         AuthenticationHelper,
diff --git a/test/authentication/service/passwordauth.service.test.ts b/test/authentication/service/passwordauth.service.test.ts
index ccdac7e..89ca024 100644
--- a/test/authentication/service/passwordauth.service.test.ts
+++ b/test/authentication/service/passwordauth.service.test.ts
@@ -6,7 +6,7 @@ import { AuthenticationHelper } from '../../../src/authentication/authentication
 import PasswordAuthService from '../../../src/authentication/service/password.auth.service';
 import { TokenService } from '../../../src/authentication/service/token.service';
 import User from '../../../src/authorization/entity/user.entity';
-import UserService from '../../../src/authorization/service/user.service';
+import { UserServiceInterface } from '../../../src/authorization/service/user.service.interface';
 import { Status } from '../../../src/schema/graphql.schema';
 
 let users: User[] = [
@@ -25,7 +25,7 @@ let users: User[] = [
 describe('test PasswordAuthService', () => {
   let passwordAuthService: PasswordAuthService;
   let authenticationHelper: AuthenticationHelper;
-  const userService = Substitute.for<UserService>();
+  const userService = Substitute.for<UserServiceInterface>();
   const configService = Substitute.for<ConfigService>();
   const tokenService = Substitute.for<TokenService>();
   configService.get('ENV').returns('local');
@@ -43,9 +43,9 @@ describe('test PasswordAuthService', () => {
       imports: [ConfigModule],
       controllers: [],
       providers: [
-        { provide: 'UserService', useValue: userService },
-        { provide: 'ConfigService', useValue: configService },
-        { provide: 'TokenService', useValue: tokenService },
+        { provide: UserServiceInterface, useValue: userService },
+        { provide: ConfigService, useValue: configService },
+        { provide: TokenService, useValue: tokenService },
         {
           provide: DataSource,
           useValue: mockDataSource,
diff --git a/test/authentication/service/token.service.test.ts b/test/authentication/service/token.service.test.ts
index ca8a8de..a9590fa 100644
--- a/test/authentication/service/token.service.test.ts
+++ b/test/authentication/service/token.service.test.ts
@@ -8,12 +8,12 @@ import {
 import { AuthenticationHelper } from '../../../src/authentication/authentication.helper';
 import { TokenService } from '../../../src/authentication/service/token.service';
 import User from '../../../src/authorization/entity/user.entity';
-import UserService from '../../../src/authorization/service/user.service';
+import { UserServiceInterface } from '../../../src/authorization/service/user.service.interface';
 
 describe('test TokenService', () => {
   let tokenService: TokenService;
   let authenticationHelper: AuthenticationHelper;
-  const userService = Substitute.for<UserService>();
+  const userService = Substitute.for<UserServiceInterface>();
   const configService = Substitute.for<ConfigService>();
   configService.get('ENV').returns('local');
   configService.get('JWT_SECRET').returns('s3cr3t1234567890');
@@ -24,8 +24,8 @@ describe('test TokenService', () => {
       imports: [ConfigModule],
       controllers: [],
       providers: [
-        { provide: 'UserService', useValue: userService },
-        { provide: 'ConfigService', useValue: configService },
+        { provide: UserServiceInterface, useValue: userService },
+        { provide: ConfigService, useValue: configService },
         TokenService,
         AuthenticationHelper,
       ],
diff --git a/test/authorization/resolver/entity.resolver.test.ts b/test/authorization/resolver/entity.resolver.test.ts
index cc6b071..ade13d8 100644
--- a/test/authorization/resolver/entity.resolver.test.ts
+++ b/test/authorization/resolver/entity.resolver.test.ts
@@ -1,8 +1,14 @@
 import Substitute, { Arg } from '@fluffy-spoon/substitute';
 import { INestApplication } from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
 import { Test, TestingModule } from '@nestjs/testing';
-import { AppGraphQLModule } from '../../../src/graphql/graphql.module';
 import * as request from 'supertest';
+import { AuthenticationHelper } from '../../../src/authentication/authentication.helper';
+import User from '../../../src/authorization/entity/user.entity';
+import { EntityResolver } from '../../../src/authorization/resolver/entity.resolver';
+import { EntityServiceInterface } from '../../../src/authorization/service/entity.service.interface';
+import { UserServiceInterface } from '../../../src/authorization/service/user.service.interface';
+import { AppGraphQLModule } from '../../../src/graphql/graphql.module';
 import {
   Entity,
   NewEntityInput,
@@ -10,13 +16,7 @@ import {
   UpdateEntityInput,
   UpdateEntityPermissionInput,
 } from '../../../src/schema/graphql.schema';
-import { EntityResolver } from '../../../src/authorization/resolver/entity.resolver';
-import { AuthenticationHelper } from '../../../src/authentication/authentication.helper';
-import UserService from '../../../src/authorization/service/user.service';
-import User from '../../../src/authorization/entity/user.entity';
 import { mockedConfigService } from '../../utils/mocks/config.service';
-import { EntityServiceInterface } from '../../../src/authorization/service/entity.service.interface';
-import { ConfigService } from '@nestjs/config';
 
 const gql = '/graphql';
 
@@ -56,7 +56,8 @@ const entities: Entity[] = [
 ];
 
 const entityService = Substitute.for<EntityServiceInterface>();
-const userService = Substitute.for<UserService>();
+const userService = Substitute.for<UserServiceInterface>();
+
 describe('Entity Module', () => {
   let app: INestApplication;
   userService
@@ -70,7 +71,7 @@ describe('Entity Module', () => {
       providers: [
         EntityResolver,
         { provide: EntityServiceInterface, useValue: entityService },
-        { provide: UserService, useValue: userService },
+        { provide: UserServiceInterface, useValue: userService },
         { provide: ConfigService, useValue: mockedConfigService },
         AuthenticationHelper,
       ],
diff --git a/test/authorization/resolver/group.resolver.test.ts b/test/authorization/resolver/group.resolver.test.ts
index 8d7f138..9329ed5 100644
--- a/test/authorization/resolver/group.resolver.test.ts
+++ b/test/authorization/resolver/group.resolver.test.ts
@@ -1,25 +1,24 @@
 import Substitute, { Arg } from '@fluffy-spoon/substitute';
 import { INestApplication } from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
 import { Test, TestingModule } from '@nestjs/testing';
-import { AppGraphQLModule } from '../../../src/graphql/graphql.module';
+import Permission from 'src/authorization/entity/permission.entity';
+import Role from 'src/authorization/entity/role.entity';
+import * as request from 'supertest';
+import { AuthenticationHelper } from '../../../src/authentication/authentication.helper';
 import Group from '../../../src/authorization/entity/group.entity';
-import { GroupService } from '../../../src/authorization/service/group.service';
+import User from '../../../src/authorization/entity/user.entity';
 import { GroupResolver } from '../../../src/authorization/resolver/group.resolver';
-import * as request from 'supertest';
+import { GroupServiceInterface } from '../../../src/authorization/service/group.service.interface';
+import { UserServiceInterface } from '../../../src/authorization/service/user.service.interface';
+import { AppGraphQLModule } from '../../../src/graphql/graphql.module';
+import * as GqlSchema from '../../../src/schema/graphql.schema';
 import {
   NewGroupInput,
   UpdateGroupInput,
   UpdateGroupPermissionInput,
 } from '../../../src/schema/graphql.schema';
-import { AuthenticationHelper } from '../../../src/authentication/authentication.helper';
-import User from '../../../src/authorization/entity/user.entity';
-import UserService from '../../../src/authorization/service/user.service';
 import { mockedConfigService } from '../../utils/mocks/config.service';
-import Role from 'src/authorization/entity/role.entity';
-import * as GqlSchema from '../../../src/schema/graphql.schema';
-import Permission from 'src/authorization/entity/permission.entity';
-import { GroupServiceInterface } from '../../../src/authorization/service/group.service.interface';
-import { ConfigService } from '@nestjs/config';
 
 const gql = '/graphql';
 
@@ -53,7 +52,7 @@ const groupService = Substitute.for<GroupServiceInterface>();
 describe('Group Module', () => {
   let app: INestApplication;
 
-  const userService = Substitute.for<UserService>();
+  const userService = Substitute.for<UserServiceInterface>();
   let authenticationHelper: AuthenticationHelper;
   beforeAll(async () => {
     userService
@@ -65,7 +64,7 @@ describe('Group Module', () => {
         AuthenticationHelper,
         GroupResolver,
         { provide: GroupServiceInterface, useValue: groupService },
-        { provide: UserService, useValue: userService },
+        { provide: UserServiceInterface, useValue: userService },
         { provide: ConfigService, useValue: mockedConfigService },
       ],
     }).compile();
diff --git a/test/authorization/resolver/permission.resolver.test.ts b/test/authorization/resolver/permission.resolver.test.ts
index 611169a..0780f43 100644
--- a/test/authorization/resolver/permission.resolver.test.ts
+++ b/test/authorization/resolver/permission.resolver.test.ts
@@ -2,20 +2,20 @@ import Substitute, { Arg } from '@fluffy-spoon/substitute';
 import { INestApplication } from '@nestjs/common';
 import { ConfigService } from '@nestjs/config';
 import { Test, TestingModule } from '@nestjs/testing';
-import { AppGraphQLModule } from '../../../src/graphql/graphql.module';
 import * as request from 'supertest';
+import { AuthenticationHelper } from '../../../src/authentication/authentication.helper';
+import Permission from '../../../src/authorization/entity/permission.entity';
+import User from '../../../src/authorization/entity/user.entity';
+import { PermissionResolver } from '../../../src/authorization/resolver/permission.resolver';
+import { PermissionServiceInterface } from '../../../src/authorization/service/permission.service.interface';
+import { UserServiceInterface } from '../../../src/authorization/service/user.service.interface';
+import { AppGraphQLModule } from '../../../src/graphql/graphql.module';
 import {
   NewPermissionInput,
   Status,
   UpdatePermissionInput,
 } from '../../../src/schema/graphql.schema';
-import Permission from '../../../src/authorization/entity/permission.entity';
-import { PermissionResolver } from '../../../src/authorization/resolver/permission.resolver';
-import UserService from '../../../src/authorization/service/user.service';
 import { mockedConfigService } from '../../utils/mocks/config.service';
-import { AuthenticationHelper } from '../../../src/authentication/authentication.helper';
-import User from '../../../src/authorization/entity/user.entity';
-import { PermissionServiceInterface } from '../../../src/authorization/service/permission.service.interface';
 
 const gql = '/graphql';
 const users: User[] = [
@@ -37,7 +37,8 @@ const permissions: Permission[] = [
   },
 ];
 const permissionService = Substitute.for<PermissionServiceInterface>();
-const userService = Substitute.for<UserService>();
+const userService = Substitute.for<UserServiceInterface>();
+
 describe('Permission Module', () => {
   let app: INestApplication;
   let token: string;
@@ -47,7 +48,7 @@ describe('Permission Module', () => {
       providers: [
         PermissionResolver,
         { provide: PermissionServiceInterface, useValue: permissionService },
-        { provide: UserService, useValue: userService },
+        { provide: UserServiceInterface, useValue: userService },
         { provide: ConfigService, useValue: mockedConfigService },
         AuthenticationHelper,
       ],
diff --git a/test/authorization/resolver/role.resolver.test.ts b/test/authorization/resolver/role.resolver.test.ts
index f636a61..f90e884 100644
--- a/test/authorization/resolver/role.resolver.test.ts
+++ b/test/authorization/resolver/role.resolver.test.ts
@@ -1,23 +1,23 @@
 import Substitute, { Arg } from '@fluffy-spoon/substitute';
 import { INestApplication } from '@nestjs/common';
-import { Test, TestingModule } from '@nestjs/testing';
 import { ConfigService } from '@nestjs/config';
-import { AppGraphQLModule } from '../../../src/graphql/graphql.module';
+import { Test, TestingModule } from '@nestjs/testing';
+import Permission from 'src/authorization/entity/permission.entity';
 import * as request from 'supertest';
+import { AuthenticationHelper } from '../../../src/authentication/authentication.helper';
+import Role from '../../../src/authorization/entity/role.entity';
+import User from '../../../src/authorization/entity/user.entity';
+import { RoleResolver } from '../../../src/authorization/resolver/role.resolver';
+import { RoleServiceInterface } from '../../../src/authorization/service/role.service.interface';
+import { UserServiceInterface } from '../../../src/authorization/service/user.service.interface';
+import { AppGraphQLModule } from '../../../src/graphql/graphql.module';
+import * as GqlSchema from '../../../src/schema/graphql.schema';
 import {
   NewRoleInput,
   UpdateRoleInput,
   UpdateRolePermissionInput,
 } from '../../../src/schema/graphql.schema';
-import { AuthenticationHelper } from '../../../src/authentication/authentication.helper';
-import User from '../../../src/authorization/entity/user.entity';
-import UserService from '../../../src/authorization/service/user.service';
 import { mockedConfigService } from '../../utils/mocks/config.service';
-import { RoleResolver } from '../../../src/authorization/resolver/role.resolver';
-import Role from '../../../src/authorization/entity/role.entity';
-import * as GqlSchema from '../../../src/schema/graphql.schema';
-import Permission from 'src/authorization/entity/permission.entity';
-import { RoleServiceInterface } from '../../../src/authorization/service/role.service.interface';
 
 const gql = '/graphql';
 
@@ -51,7 +51,7 @@ const roleService = Substitute.for<RoleServiceInterface>();
 describe('Role Module', () => {
   let app: INestApplication;
 
-  const userService = Substitute.for<UserService>();
+  const userService = Substitute.for<UserServiceInterface>();
   let authenticationHelper: AuthenticationHelper;
   beforeAll(async () => {
     userService
@@ -63,7 +63,7 @@ describe('Role Module', () => {
         AuthenticationHelper,
         RoleResolver,
         { provide: RoleServiceInterface, useValue: roleService },
-        { provide: UserService, useValue: userService },
+        { provide: UserServiceInterface, useValue: userService },
         { provide: ConfigService, useValue: mockedConfigService },
       ],
     }).compile();
diff --git a/test/authorization/resolver/user.resolver.test.ts b/test/authorization/resolver/user.resolver.test.ts
index ed8d8a3..be670cd 100644
--- a/test/authorization/resolver/user.resolver.test.ts
+++ b/test/authorization/resolver/user.resolver.test.ts
@@ -1,7 +1,7 @@
 import { Test, TestingModule } from '@nestjs/testing';
 import * as request from 'supertest';
 import { INestApplication } from '@nestjs/common';
-import UserService from '../../../src/authorization/service/user.service';
+import { UserServiceInterface } from '../../../src/authorization/service/user.service.interface';
 import Substitute from '@fluffy-spoon/substitute';
 import User from '../../../src/authorization/entity/user.entity';
 import { UserResolver } from '../../../src/authorization/resolver/user.resolver';
@@ -62,7 +62,7 @@ const groups: Group[] = [
 
 const gql = '/graphql';
 
-const userService = Substitute.for<UserService>();
+const userService = Substitute.for<UserServiceInterface>();
 
 describe('User Module', () => {
   let app: INestApplication;
@@ -76,8 +76,8 @@ describe('User Module', () => {
       providers: [
         UserResolver,
         AuthenticationHelper,
-        { provide: 'ConfigService', useValue: configService },
-        { provide: 'UserService', useValue: userService },
+        { provide: ConfigService, useValue: configService },
+        { provide: UserServiceInterface, useValue: userService },
       ],
     }).compile();
     authenticationHelper = moduleFixture.get<AuthenticationHelper>(
diff --git a/test/authorization/service/group.service.test.ts b/test/authorization/service/group.service.test.ts
index 0141bf6..1feaf31 100644
--- a/test/authorization/service/group.service.test.ts
+++ b/test/authorization/service/group.service.test.ts
@@ -18,7 +18,7 @@ import { GroupService } from '../../../src/authorization/service/group.service';
 import { GroupServiceInterface } from '../../../src/authorization/service/group.service.interface';
 import { GroupCacheServiceInterface } from '../../../src/authorization/service/groupcache.service.interface';
 import SearchService from '../../../src/authorization/service/search.service';
-import UserCacheService from '../../../src/authorization/service/usercache.service';
+import { UserCacheServiceInterface } from '../../../src/authorization/service/usercache.service.interface';
 import { RedisCacheService } from '../../../src/cache/redis-cache/redis-cache.service';
 import {
   NewGroupInput,
@@ -72,7 +72,7 @@ describe('test Group Service', () => {
   const redisCacheService = Substitute.for<RedisCacheService>();
   const groupRoleRepository = Substitute.for<Repository<GroupRole>>();
   const roleRepository = Substitute.for<Repository<Role>>();
-  const userCacheService = Substitute.for<UserCacheService>();
+  const userCacheService = Substitute.for<UserCacheServiceInterface>();
   const searchService = Substitute.for<SearchService>();
   const userQueryBuilder = Substitute.for<SelectQueryBuilder<User>>();
   const permissionQueryBuilder = Substitute.for<
@@ -149,7 +149,7 @@ describe('test Group Service', () => {
           provide: getRepositoryToken(Role),
           useValue: roleRepository,
         },
-        { provide: UserCacheService, useValue: userCacheService },
+        { provide: UserCacheServiceInterface, useValue: userCacheService },
         { provide: GroupCacheServiceInterface, useValue: groupCacheService },
         { provide: RedisCacheService, useValue: redisCacheService },
         { provide: SearchService, useValue: searchService },
diff --git a/test/authorization/service/user.service.test.ts b/test/authorization/service/user.service.test.ts
index d875d26..622cd66 100644
--- a/test/authorization/service/user.service.test.ts
+++ b/test/authorization/service/user.service.test.ts
@@ -18,8 +18,9 @@ import { GroupCacheServiceInterface } from '../../../src/authorization/service/g
 import { PermissionCacheServiceInterface } from '../../../src/authorization/service/permissioncache.service.interface';
 import { RoleCacheServiceInterface } from '../../../src/authorization/service/rolecache.service.interface';
 import SearchService from '../../../src/authorization/service/search.service';
-import UserService from '../../../src/authorization/service/user.service';
-import UserCacheService from '../../../src/authorization/service/usercache.service';
+import { UserService } from '../../../src/authorization/service/user.service';
+import { UserServiceInterface } from '../../../src/authorization/service/user.service.interface';
+import { UserCacheServiceInterface } from '../../../src/authorization/service/usercache.service.interface';
 import { RedisCacheService } from '../../../src/cache/redis-cache/redis-cache.service';
 import { Status } from '../../../src/schema/graphql.schema';
 
@@ -52,7 +53,7 @@ const groups: Group[] = [
 ];
 
 describe('test UserService', () => {
-  let userService: UserService;
+  let userService: UserServiceInterface;
   let userRepository: UserRepository;
 
   let createQueryBuilderMock: jest.Mock;
@@ -72,7 +73,7 @@ describe('test UserService', () => {
   >();
   const groupRoleRepository = Substitute.for<Repository<GroupRole>>();
   const rolePermissionRepository = Substitute.for<Repository<RolePermission>>();
-  const userCacheService = Substitute.for<UserCacheService>();
+  const userCacheService = Substitute.for<UserCacheServiceInterface>();
   const groupCacheService = Substitute.for<GroupCacheServiceInterface>();
   const permissionCacheService = Substitute.for<PermissionCacheServiceInterface>();
   const redisCacheService = Substitute.for<RedisCacheService>();
@@ -125,7 +126,7 @@ describe('test UserService', () => {
           provide: getRepositoryToken(RolePermission),
           useValue: rolePermissionRepository,
         },
-        { provide: UserCacheService, useValue: userCacheService },
+        { provide: UserCacheServiceInterface, useValue: userCacheService },
         { provide: GroupCacheServiceInterface, useValue: groupCacheService },
         { provide: RedisCacheService, useValue: redisCacheService },
         { provide: SearchService, useValue: searchService },
@@ -141,7 +142,7 @@ describe('test UserService', () => {
         },
       ],
     }).compile();
-    userService = moduleRef.get(UserService);
+    userService = moduleRef.get<UserServiceInterface>(UserService);
     userRepository = moduleRef.get(UserRepository);
 
     getUserByIdMock = userRepository.getUserById = jest.fn();