diff --git a/.github/workflows/ci-build-test.yml b/.github/workflows/ci-build-test.yml
new file mode 100644
index 0000000..ba3859b
--- /dev/null
+++ b/.github/workflows/ci-build-test.yml
@@ -0,0 +1,32 @@
+name: CI Build & Test
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+
+jobs:
+  build-test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v3
+        with:
+          java-version: '17'
+          distribution: 'temurin'
+
+      - name: Cache Maven
+        uses: actions/cache@v3
+        with:
+          path: ~/.m2
+          key: maven-${{ hashFiles('**/pom.xml') }}
+
+      - name: Build & Test
+        run: mvn clean test -B
+
+      - name: Package (skip tests)
+        run: mvn package -DskipTests -B
diff --git a/src/main/java/com/kubuski/urlshortener/config/SecurityConfig.java b/src/main/java/com/kubuski/urlshortener/config/SecurityConfig.java
index d53b5f6..a8f551d 100644
--- a/src/main/java/com/kubuski/urlshortener/config/SecurityConfig.java
+++ b/src/main/java/com/kubuski/urlshortener/config/SecurityConfig.java
@@ -45,7 +45,8 @@ public SecurityFilterChain securityFilterChain(HttpSecurity httpSecurity) throws
         httpSecurity
                 .csrf(AbstractHttpConfigurer::disable)
                 .authorizeHttpRequests(auth -> auth
-                        .requestMatchers(SHORTEN_PERMIT_PATHS).hasAnyRole(String.valueOf(Roles.USER), String.valueOf(Roles.ADMIN))
+                        .requestMatchers(SHORTEN_PERMIT_PATHS)
+                        .hasAnyRole(String.valueOf(Roles.USER), String.valueOf(Roles.ADMIN))
                         .requestMatchers(SWAGGER_UI_PATHS).permitAll()
                         .requestMatchers(USER_PERMIT_PATHS).hasRole(String.valueOf(Roles.ADMIN))
                         .requestMatchers(URL_PERMIT_PATHS).hasRole(String.valueOf(Roles.USER))
diff --git a/src/main/java/com/kubuski/urlshortener/service/AuthenticationService.java b/src/main/java/com/kubuski/urlshortener/service/AuthenticationService.java
index ed42e5c..228af43 100644
--- a/src/main/java/com/kubuski/urlshortener/service/AuthenticationService.java
+++ b/src/main/java/com/kubuski/urlshortener/service/AuthenticationService.java
@@ -1,18 +1,18 @@
 package com.kubuski.urlshortener.service;
 
+import com.kubuski.urlshortener.dto.AuthenticationRequest;
+import com.kubuski.urlshortener.dto.AuthenticationResponse;
+import com.kubuski.urlshortener.dto.RegisterRequest;
+import com.kubuski.urlshortener.entity.User;
 import com.kubuski.urlshortener.exception.UserAlreadyExistsException;
+import com.kubuski.urlshortener.repository.UserRepository;
+import lombok.RequiredArgsConstructor;
 import org.springframework.security.authentication.AuthenticationManager;
 import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
 import org.springframework.security.core.userdetails.UsernameNotFoundException;
 import org.springframework.security.crypto.password.PasswordEncoder;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
-import com.kubuski.urlshortener.dto.AuthenticationRequest;
-import com.kubuski.urlshortener.dto.AuthenticationResponse;
-import com.kubuski.urlshortener.dto.RegisterRequest;
-import com.kubuski.urlshortener.entity.User;
-import com.kubuski.urlshortener.repository.UserRepository;
-import lombok.RequiredArgsConstructor;
 
 @Service
 @RequiredArgsConstructor
@@ -60,8 +60,15 @@ private User findUserByLogin(String login) {
     }
 
     private void checkIfUserExists(String email, String username) {
-        if (userRepository.findByEmailOrUsername(email).isPresent() || userRepository.findByEmailOrUsername(username).isPresent()) {
-            throw new UserAlreadyExistsException("User with email " + email + " or username " + username + " already exists");
+        if (userExists(email, username)) {
+            throw new UserAlreadyExistsException(
+                    "User with email " + email + " or username " + username + " already exists"
+            );
         }
     }
+
+    private boolean userExists(String email, String username) {
+        return userRepository.findByEmailOrUsername(email).isPresent()
+                || userRepository.findByEmailOrUsername(username).isPresent();
+    }
 }
diff --git a/src/main/java/com/kubuski/urlshortener/service/JwtService.java b/src/main/java/com/kubuski/urlshortener/service/JwtService.java
index 840ebcd..c2b417c 100644
--- a/src/main/java/com/kubuski/urlshortener/service/JwtService.java
+++ b/src/main/java/com/kubuski/urlshortener/service/JwtService.java
@@ -41,7 +41,9 @@ public boolean isTokenValid(String token, User userDetails) {
         String subjectUsername = extractSubject(token);
         String email = extractEmail(token);
 
-        return email.equals(userDetails.getEmail()) && subjectUsername.equals(userDetails.getUsername()) && !isTokenExpired(token);
+        return email.equals(userDetails.getEmail())
+                && subjectUsername.equals(userDetails.getUsername())
+                && !isTokenExpired(token);
     }
 
     public String generateToken(User userDetails) {