diff --git a/src/test/java/dev/nmarulo/depensaapp/app/authentication/AuthenticationServiceTest.java b/src/test/java/dev/nmarulo/depensaapp/app/authentication/AuthenticationServiceTest.java
index f4adad4..a4daa72 100644
--- a/src/test/java/dev/nmarulo/depensaapp/app/authentication/AuthenticationServiceTest.java
+++ b/src/test/java/dev/nmarulo/depensaapp/app/authentication/AuthenticationServiceTest.java
@@ -1,6 +1,7 @@
 package dev.nmarulo.depensaapp.app.authentication;
 
 import dev.nmarulo.depensaapp.app.authentication.dtos.AuthenticationRes;
+import dev.nmarulo.depensaapp.app.users.User;
 import dev.nmarulo.depensaapp.app.users.UserRepository;
 import dev.nmarulo.depensaapp.configuration.AppProperties;
 import org.junit.jupiter.api.BeforeAll;
@@ -15,6 +16,7 @@
 import org.springframework.security.oauth2.jwt.*;
 
 import java.time.Instant;
+import java.time.LocalDateTime;
 import java.util.Optional;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -98,4 +100,26 @@ void testLogin() {
         }
     }
     
+    @Test
+    void testRegister() {
+        final var request = authenticationServiceTestUtil.getRegisterAuthenticationReq();
+        final var expected = authenticationServiceTestUtil.getRegisterAuthenticationRes();
+        final var newUser = authenticationServiceTestUtil.getNewUser();
+        final var userOptional = Optional.<User>empty();
+        final var localDateTime = newUser.getCreatedAt();
+        
+        when(this.userRepository.findByUsername(eq(request.getUsername()))).thenReturn(userOptional);
+        when(this.passwordEncoder.encode(eq(request.getPassword()))).thenReturn(newUser.getPassword());
+        when(this.userRepository.save(eq(newUser))).thenReturn(newUser);
+        
+        try (MockedStatic<LocalDateTime> localDateTimeMockedStatic = mockStatic(LocalDateTime.class)) {
+            localDateTimeMockedStatic.when(LocalDateTime::now)
+                                     .thenReturn(localDateTime);
+            
+            final var actual = this.authenticationService.register(request);
+            
+            assertEquals(expected, actual);
+        }
+    }
+    
 }
diff --git a/src/test/java/dev/nmarulo/depensaapp/app/authentication/AuthenticationServiceTestUtil.java b/src/test/java/dev/nmarulo/depensaapp/app/authentication/AuthenticationServiceTestUtil.java
index 81e8faa..ec63a07 100644
--- a/src/test/java/dev/nmarulo/depensaapp/app/authentication/AuthenticationServiceTestUtil.java
+++ b/src/test/java/dev/nmarulo/depensaapp/app/authentication/AuthenticationServiceTestUtil.java
@@ -3,6 +3,8 @@
 import dev.nmarulo.depensaapp.FakeTestUtil;
 import dev.nmarulo.depensaapp.app.authentication.dtos.AuthenticationReq;
 import dev.nmarulo.depensaapp.app.authentication.dtos.AuthenticationRes;
+import dev.nmarulo.depensaapp.app.authentication.dtos.RegisterAuthenticationReq;
+import dev.nmarulo.depensaapp.app.authentication.dtos.RegisterAuthenticationRes;
 import dev.nmarulo.depensaapp.app.users.User;
 import lombok.Getter;
 
@@ -21,6 +23,12 @@ public class AuthenticationServiceTestUtil {
     
     private final long plusSecondsJwtExpiresAt;
     
+    private final User newUser;
+    
+    private final RegisterAuthenticationReq registerAuthenticationReq;
+    
+    private final RegisterAuthenticationRes registerAuthenticationRes;
+    
     public AuthenticationServiceTestUtil() {
         this.user = initUser();
         
@@ -30,6 +38,18 @@ public AuthenticationServiceTestUtil() {
         this.authenticationRes = initAuthenticationRes(userRes);
         this.jwtIssuer = FakeTestUtil.randomWord();
         this.plusSecondsJwtExpiresAt = FakeTestUtil.randomLong();
+        this.newUser = initNewUser();
+        this.registerAuthenticationReq = initRegisterAuthenticationReq(newUser);
+        this.registerAuthenticationRes = new RegisterAuthenticationRes(this.newUser.getUsername());
+    }
+    
+    private RegisterAuthenticationReq initRegisterAuthenticationReq(User newUser) {
+        final var registerAuthenticationReq = new RegisterAuthenticationReq();
+        
+        registerAuthenticationReq.setUsername(newUser.getUsername());
+        registerAuthenticationReq.setPassword(FakeTestUtil.randomPassword());
+        
+        return registerAuthenticationReq;
     }
     
     private AuthenticationRes.User initUserRes(User user) {
@@ -73,4 +93,17 @@ private AuthenticationReq initAuthenticationReq(User user) {
         return authenticationReq;
     }
     
+    private User initNewUser() {
+        final var user = new User();
+        final var createdAt = FakeTestUtil.randomPast();
+        
+        user.setUsername(FakeTestUtil.randomUsername());
+        user.setPassword(FakeTestUtil.randomPassword());
+        user.setCreatedAt(createdAt);
+        user.setUpdatedAt(createdAt);
+        user.setShoppingLists(Collections.emptySet());
+        
+        return user;
+    }
+    
 }