diff --git a/src/main/java/de/bonndan/nivio/appuser/AppUser.java b/src/main/java/de/bonndan/nivio/appuser/AppUser.java
index 6855dfa9b..d629f769b 100644
--- a/src/main/java/de/bonndan/nivio/appuser/AppUser.java
+++ b/src/main/java/de/bonndan/nivio/appuser/AppUser.java
@@ -91,10 +91,6 @@ public class AppUser implements UserDetails {
     @Column
     private Boolean enabled;
 
-    public AppUser() {
-
-    }
-
     @Override
     public Collection<? extends GrantedAuthority> getAuthorities() {
         SimpleGrantedAuthority authority = new SimpleGrantedAuthority(appUserRole.name());
@@ -207,7 +203,5 @@ public void setExternalId(String externalId) {
         this.externalId = externalId;
     }
 
-    public void setIdp(String idp) {
-        this.idp = idp;
-    }
+    public void setIdp(String idp) { this.idp = idp; }
 }
\ No newline at end of file
diff --git a/src/test/java/de/bonndan/nivio/appuser/AppUserRepositoryTest.java b/src/test/java/de/bonndan/nivio/appuser/AppUserRepositoryTest.java
index c95eb7cab..03828f1d6 100644
--- a/src/test/java/de/bonndan/nivio/appuser/AppUserRepositoryTest.java
+++ b/src/test/java/de/bonndan/nivio/appuser/AppUserRepositoryTest.java
@@ -6,7 +6,8 @@
 
 import java.util.Optional;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 @DataJpaTest
 class AppUserRepositoryTest {
@@ -14,6 +15,9 @@ class AppUserRepositoryTest {
     @Autowired
     private AppUserRepository appUserRepository;
 
+    AppUserService appUserService = new AppUserService(appUserRepository);
+
+
     @Test
     void findByExternalId() {
         Optional<AppUser> appUser = Optional.of(new AppUser());
diff --git a/src/test/java/de/bonndan/nivio/appuser/AppUserServiceTest.java b/src/test/java/de/bonndan/nivio/appuser/AppUserServiceTest.java
new file mode 100644
index 000000000..4b4ab2fbf
--- /dev/null
+++ b/src/test/java/de/bonndan/nivio/appuser/AppUserServiceTest.java
@@ -0,0 +1,44 @@
+package de.bonndan.nivio.appuser;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.security.core.userdetails.UsernameNotFoundException;
+
+import java.util.Optional;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+
+@DataJpaTest
+class AppUserServiceTest {
+
+
+    @Test
+    void loadUserByUsername() {
+
+        // given
+        AppUser appUser = mock(AppUser.class);
+        AppUserRepository appUserRepository = mock(AppUserRepository.class);
+        AppUserService appUserService = new AppUserService(appUserRepository);
+
+        // when
+        doReturn(Optional.of(appUser)).when(appUserRepository).findByExternalId("123");
+        UserDetails userDetails = appUserService.loadUserByUsername("123");
+
+        // then
+        assertThat(userDetails).isEqualTo(appUser);
+        assertNull(userDetails.getUsername());
+        assertNull(userDetails.getPassword());
+        assertFalse(userDetails.isAccountNonExpired());
+        assertFalse(userDetails.isAccountNonLocked());
+        assertFalse(userDetails.isCredentialsNonExpired());
+
+        assertThrows(UsernameNotFoundException.class, () -> {
+            appUserService.loadUserByUsername("");
+        });
+    }
+
+}
\ No newline at end of file
diff --git a/src/test/java/de/bonndan/nivio/appuser/AppUserTest.java b/src/test/java/de/bonndan/nivio/appuser/AppUserTest.java
new file mode 100644
index 000000000..823f24547
--- /dev/null
+++ b/src/test/java/de/bonndan/nivio/appuser/AppUserTest.java
@@ -0,0 +1,146 @@
+package de.bonndan.nivio.appuser;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class AppUserTest {
+
+    AppUser appUser = new AppUser();
+
+    @Test
+    void isEnabled() {
+        appUser.setEnabled(true);
+        assertEquals(true, appUser.getEnabled());
+    }
+
+    @Test
+    void getId() {
+        appUser.setId(1L);
+        assertEquals(1L, appUser.getId());
+    }
+
+    @Test
+    void getName() {
+        appUser.setName("name");
+        assertEquals("name", appUser.getName());
+    }
+
+    @Test
+    void getAlias() {
+        appUser.setAlias("alias");
+        assertEquals("alias", appUser.getAlias());
+    }
+
+    @Test
+    void getEmail() {
+        appUser.setEmail("email");
+        assertEquals("email", appUser.getEmail());
+    }
+
+    @Test
+    void getAvatarUrl() {
+        appUser.setAvatarUrl("avatarUrl");
+        assertEquals("avatarUrl", appUser.getAvatarUrl());
+    }
+
+    @Test
+    void getAppUserRole() {
+        appUser.setAppUserRole(AppUserRole.USER);
+        assertEquals(AppUserRole.USER, appUser.getAppUserRole());
+    }
+
+    @Test
+    void getExternalId() {
+        appUser.setExternalId("123");
+        assertEquals("123", appUser.getExternalId());
+    }
+
+    @Test
+    void getIdp() {
+        appUser.setIdp("github");
+        assertEquals("github", appUser.getIdp());
+    }
+
+    @Test
+    void getLocked() {
+        appUser.setLocked(false);
+        assertEquals(false, appUser.getLocked());
+    }
+
+    @Test
+    void getEnabled() {
+        appUser.setEnabled(true);
+        assertEquals(true, appUser.getEnabled());
+    }
+
+    @Test
+    void setId() {
+        Long id = 1L;
+        appUser.setId(id);
+        assertEquals(id, appUser.getId());
+    }
+
+    @Test
+    void setName() {
+        String name = "name";
+        appUser.setName(name);
+        assertEquals(name, appUser.getName());
+    }
+
+    @Test
+    void setAlias() {
+        String alias = "login";
+        appUser.setAlias(alias);
+        assertEquals(alias, appUser.getAlias());
+    }
+
+    @Test
+    void setEmail() {
+        String email = "email";
+        appUser.setEmail(email);
+        assertEquals(email, appUser.getEmail());
+    }
+
+    @Test
+    void setAvatarUrl() {
+        String avatarUrl = "avatarUrl";
+        appUser.setAvatarUrl(avatarUrl);
+        assertEquals(avatarUrl, appUser.getAvatarUrl());
+    }
+
+    @Test
+    void setAppUserRole() {
+        appUser.setAppUserRole(AppUserRole.USER);
+        assertEquals(AppUserRole.USER, appUser.getAppUserRole());
+    }
+
+    @Test
+    void setLocked() {
+        Boolean locked = false;
+        appUser.setLocked(locked);
+        assertEquals(locked, appUser.getLocked());
+    }
+
+    @Test
+    void setEnabled() {
+        Boolean enabled = true;
+        appUser.setEnabled(enabled);
+        assertEquals(enabled, appUser.getEnabled());
+    }
+
+    @Test
+    void setExternalId() {
+        String externalId = "123";
+        appUser.setExternalId(externalId);
+        assertEquals(externalId, appUser.getExternalId());
+    }
+
+    @Test
+    void setIdp() {
+        String idp = "github";
+        appUser.setIdp(idp);
+        assertEquals(idp, appUser.getIdp());
+    }
+}
\ No newline at end of file