diff --git a/backend/src/main/java/com/github/egnaf/spring_boot_docker_example/service/UserService.java b/backend/src/main/java/com/github/egnaf/spring_boot_docker_example/service/UserService.java
index 62bdebb..34fbe52 100644
--- a/backend/src/main/java/com/github/egnaf/spring_boot_docker_example/service/UserService.java
+++ b/backend/src/main/java/com/github/egnaf/spring_boot_docker_example/service/UserService.java
@@ -1,12 +1,14 @@
 package com.github.egnaf.spring_boot_docker_example.service;
 
 import com.github.egnaf.spring_boot_docker_example.domain.User;
+import com.github.egnaf.spring_boot_docker_example.exception.UserExistsException;
+import com.github.egnaf.spring_boot_docker_example.exception.UserNotFoundException;
 
 import java.util.List;
 
 public interface UserService {
 
     List<User> getUsers();
-    User getUser(long id);
-    User addUser(String nickname, String email, String password);
+    User getUser(long id) throws UserNotFoundException;
+    User addUser(String nickname, String email, String password) throws UserExistsException;
 }
diff --git a/backend/src/main/java/com/github/egnaf/spring_boot_docker_example/service/impl/UserServiceImpl.java b/backend/src/main/java/com/github/egnaf/spring_boot_docker_example/service/impl/UserServiceImpl.java
index 667e03a..5ee62ee 100644
--- a/backend/src/main/java/com/github/egnaf/spring_boot_docker_example/service/impl/UserServiceImpl.java
+++ b/backend/src/main/java/com/github/egnaf/spring_boot_docker_example/service/impl/UserServiceImpl.java
@@ -5,6 +5,7 @@
 import com.github.egnaf.spring_boot_docker_example.exception.UserNotFoundException;
 import com.github.egnaf.spring_boot_docker_example.repository.UserRepository;
 import com.github.egnaf.spring_boot_docker_example.service.UserService;
+import lombok.extern.slf4j.Slf4j;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
@@ -12,6 +13,7 @@
 import java.util.Optional;
 
 @Service
+@Slf4j
 public class UserServiceImpl implements UserService {
 
     private final UserRepository userRepository;
@@ -33,6 +35,7 @@ public User getUser(long id) {
         if (user.isPresent()) {
             return user.get();
         } else {
+            log.info(String.valueOf(user.orElse(null)));
             throw new UserNotFoundException();
         }
     }
diff --git a/backend/src/test/java/com/github/egnaf/spring_boot_docker_example/service/impl/UserServiceImplTest.java b/backend/src/test/java/com/github/egnaf/spring_boot_docker_example/service/impl/UserServiceImplTest.java
index 76063b8..dd5b54c 100644
--- a/backend/src/test/java/com/github/egnaf/spring_boot_docker_example/service/impl/UserServiceImplTest.java
+++ b/backend/src/test/java/com/github/egnaf/spring_boot_docker_example/service/impl/UserServiceImplTest.java
@@ -1,11 +1,11 @@
 package com.github.egnaf.spring_boot_docker_example.service.impl;
 
 import com.github.egnaf.spring_boot_docker_example.domain.User;
+import com.github.egnaf.spring_boot_docker_example.exception.UserExistsException;
 import com.github.egnaf.spring_boot_docker_example.exception.UserNotFoundException;
 import com.github.egnaf.spring_boot_docker_example.repository.UserRepository;
 import com.github.egnaf.spring_boot_docker_example.service.UserService;
 import lombok.extern.slf4j.Slf4j;
-import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -13,6 +13,9 @@
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.test.context.junit4.SpringRunner;
 
+import java.util.ArrayList;
+import java.util.List;
+
 import static org.junit.Assert.assertEquals;
 
 @Slf4j
@@ -38,14 +41,41 @@ public void setUp() {
     }
 
     @Test
-    public void getUserTest() throws UserNotFoundException {
-        User actual = userService.getUser(1L);
+    public void getUsers() {
+        //expected
+        List<User> expected = new ArrayList<>();
+        expected.add(new User(1L, "user1", "user1@mail.com", "pass"));
+        expected.add(new User(2L, "user2", "user2@mail.com", "test"));
+
+        //actual
+        List<User> actual = userService.getUsers();
+
+        //assert
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void getUser() throws UserNotFoundException {
+        //expected
         User expected = new User(1L, "user1", "user1@mail.com", "pass");
+
+        //actual
+        User actual = userService.getUser(1L);
+
+        //assert
         assertEquals(expected, actual);
     }
 
-    @After
-    public void tearDown() {
-        userRepository.deleteAll();
+    @Test
+    public void addUser() throws UserExistsException {
+        //expected
+        User expected = new User(3L, "user3", "user3@mail.com", "demo");
+
+        //actual
+        User actual = userService.addUser(expected.getNickname(), expected.getEmail(), expected.getPassword());
+        userRepository.deleteById(3L);
+
+        //assert
+        assertEquals(expected, actual);
     }
 }