feat: add comprehensive test coverage for Book and Category entities

pom.xml

@@ -38,6 +38,7 @@
 		<lombok.mapstruct.binding.version>0.2.0</lombok.mapstruct.binding.version>
 		<mapstruct.version>1.5.5.Final</mapstruct.version>
         <jjwt.version>0.11.5</jjwt.version>
+        <testcontainers.version>1.19.0</testcontainers.version>
 	</properties>
 	<dependencies>
 		<dependency>
@@ -73,11 +74,6 @@
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-validation</artifactId>
 		</dependency>
-		<dependency>
-			<groupId>com.h2database</groupId>
-			<artifactId>h2</artifactId>
-			<scope>test</scope>
-		</dependency>
         <dependency>
             <groupId>org.liquibase</groupId>
             <artifactId>liquibase-core</artifactId>
@@ -105,24 +101,57 @@
             <artifactId>jjwt-api</artifactId>
             <version>${jjwt.version}</version>
         </dependency>
-
         <dependency>
             <groupId>io.jsonwebtoken</groupId>
             <artifactId>jjwt-impl</artifactId>
             <version>${jjwt.version}</version>
             <scope>runtime</scope>
         </dependency>
-
         <dependency>
             <groupId>io.jsonwebtoken</groupId>
             <artifactId>jjwt-jackson</artifactId>
             <version>${jjwt.version}</version>
             <scope>runtime</scope>
         </dependency>
-
+        <dependency>
+            <groupId>org.springframework.data</groupId>
+            <artifactId>spring-data-jdbc</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.testcontainers</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.testcontainers</groupId>
+            <artifactId>mysql</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>mysql</groupId>
+            <artifactId>mysql-connector-java</artifactId>
+            <version>8.0.33</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.security</groupId>
+            <artifactId>spring-security-test</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
-	<build>
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.testcontainers</groupId>
+                <artifactId>testcontainers-bom</artifactId>
+                <version>1.21.3</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+
+    <build>
 		<plugins>
 			<plugin>
 				<groupId>org.springframework.boot</groupId>

src/main/java/bookrepo/repository/book/BookRepository.java

@@ -2,9 +2,16 @@
 
 import bookrepo.model.Book;
 import java.util.List;
+import java.util.Optional;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
 
 public interface BookRepository extends JpaRepository<Book, Long>, JpaSpecificationExecutor<Book> {
     List<Book> findAllByCategories_Id(Long categoryId);
+
+    @Query("SELECT b FROM Book b JOIN FETCH b.categories WHERE b.id = :id")
+    Optional<Book> findByIdWithCategories(@Param("id") Long id);
+
 }

src/test/java/bookrepo/BookRepoApplicationTests.java

@@ -2,10 +2,8 @@
 
 import org.junit.jupiter.api.Test;
 import org.springframework.boot.test.context.SpringBootTest;
-import org.springframework.test.context.ActiveProfiles;
 
 @SpringBootTest
-@ActiveProfiles("test")
 class BookRepoApplicationTests {
     @Test
     void contextLoads() {

src/test/java/bookrepo/config/CustomMySqlContainer.java

@@ -0,0 +1,33 @@
+package bookrepo.config;
+
+import org.testcontainers.containers.MySQLContainer;
+
+public class CustomMySqlContainer extends MySQLContainer<CustomMySqlContainer> {
+    private static final String DB_IMAGE = "mysql:8";
+
+    private static CustomMySqlContainer mysqlContainer;
+
+    private CustomMySqlContainer() {
+        super(DB_IMAGE);
+    }
+
+    public static synchronized CustomMySqlContainer getInstance() {
+        if (mysqlContainer == null) {
+            mysqlContainer = new CustomMySqlContainer();
+        }
+        return mysqlContainer;
+    }
+
+    @Override
+    public void start() {
+        super.start();
+        System.setProperty("TEST_DB_URL", mysqlContainer.getJdbcUrl());
+        System.setProperty("TEST_DB_USERNAME", mysqlContainer.getUsername());
+        System.setProperty("TEST_DB_PASSWORD", mysqlContainer.getPassword());
+    }
+
+    @Override
+    public void stop() {
+    }
+}
+