diff --git a/src/main/java/io/wkrzywiec/hexagonal/library/inventory/InventoryFacade.java b/src/main/java/io/wkrzywiec/hexagonal/library/inventory/InventoryFacade.java
index 4e77087..0ac1738 100644
--- a/src/main/java/io/wkrzywiec/hexagonal/library/inventory/InventoryFacade.java
+++ b/src/main/java/io/wkrzywiec/hexagonal/library/inventory/InventoryFacade.java
@@ -19,6 +19,7 @@ public class InventoryFacade implements AddNewBook{
     @Override
     public void handle(AddNewBookCommand addNewBookCommand){
         Book book = getBookDetails.handle(addNewBookCommand.getGoogleBookId());
-        database.save(book);
+        Book savedBook = database.save(book);
+
     }
 }
diff --git a/src/main/java/io/wkrzywiec/hexagonal/library/inventory/infrastructure/InventoryDatabaseAdapter.java b/src/main/java/io/wkrzywiec/hexagonal/library/inventory/infrastructure/InventoryDatabaseAdapter.java
index 07d5a39..0600e06 100644
--- a/src/main/java/io/wkrzywiec/hexagonal/library/inventory/infrastructure/InventoryDatabaseAdapter.java
+++ b/src/main/java/io/wkrzywiec/hexagonal/library/inventory/infrastructure/InventoryDatabaseAdapter.java
@@ -10,7 +10,7 @@ class InventoryDatabaseAdapter implements InventoryDatabase {
     private final BookRepository repository;
 
     @Override
-    public void save(Book book) {
-        repository.save(book);
+    public Book save(Book book) {
+        return repository.save(book);
     }
 }
diff --git a/src/main/java/io/wkrzywiec/hexagonal/library/inventory/model/Book.java b/src/main/java/io/wkrzywiec/hexagonal/library/inventory/model/Book.java
index b8c770b..4e81980 100644
--- a/src/main/java/io/wkrzywiec/hexagonal/library/inventory/model/Book.java
+++ b/src/main/java/io/wkrzywiec/hexagonal/library/inventory/model/Book.java
@@ -67,6 +67,10 @@ public class Book {
         this.imageLink = imageLink;
     }
 
+    public Long getIdAsLong(){
+        return id;
+    }
+
     private Book() {
     }
 }
diff --git a/src/main/java/io/wkrzywiec/hexagonal/library/inventory/model/NewBookWasAddedEvent.java b/src/main/java/io/wkrzywiec/hexagonal/library/inventory/model/NewBookWasAddedEvent.java
new file mode 100644
index 0000000..2e38851
--- /dev/null
+++ b/src/main/java/io/wkrzywiec/hexagonal/library/inventory/model/NewBookWasAddedEvent.java
@@ -0,0 +1,4 @@
+package io.wkrzywiec.hexagonal.library.inventory.model;
+
+public class NewBookWasAddedEvent {
+}
diff --git a/src/main/java/io/wkrzywiec/hexagonal/library/inventory/ports/outgoing/EventPublisher.java b/src/main/java/io/wkrzywiec/hexagonal/library/inventory/ports/outgoing/EventPublisher.java
new file mode 100644
index 0000000..8ea321e
--- /dev/null
+++ b/src/main/java/io/wkrzywiec/hexagonal/library/inventory/ports/outgoing/EventPublisher.java
@@ -0,0 +1,7 @@
+package io.wkrzywiec.hexagonal.library.inventory.ports.outgoing;
+
+import io.wkrzywiec.hexagonal.library.inventory.model.NewBookWasAddedEvent;
+
+public interface EventPublisher {
+    void publishNewBookWasAddedEvent(NewBookWasAddedEvent event);
+}
diff --git a/src/main/java/io/wkrzywiec/hexagonal/library/inventory/ports/outgoing/InventoryDatabase.java b/src/main/java/io/wkrzywiec/hexagonal/library/inventory/ports/outgoing/InventoryDatabase.java
index 2c5ddf8..943ebef 100644
--- a/src/main/java/io/wkrzywiec/hexagonal/library/inventory/ports/outgoing/InventoryDatabase.java
+++ b/src/main/java/io/wkrzywiec/hexagonal/library/inventory/ports/outgoing/InventoryDatabase.java
@@ -3,5 +3,5 @@ package io.wkrzywiec.hexagonal.library.inventory.ports.outgoing;
 import io.wkrzywiec.hexagonal.library.inventory.model.Book;
 
 public interface InventoryDatabase {
-    void save(Book book);
+    Book save(Book book);
 }
diff --git a/src/test/java/io/wkrzywiec/hexagonal/library/inventory/InMemoryInventoryDatabase.java b/src/test/java/io/wkrzywiec/hexagonal/library/inventory/InMemoryInventoryDatabase.java
index da0da4f..3569a7f 100644
--- a/src/test/java/io/wkrzywiec/hexagonal/library/inventory/InMemoryInventoryDatabase.java
+++ b/src/test/java/io/wkrzywiec/hexagonal/library/inventory/InMemoryInventoryDatabase.java
@@ -2,6 +2,7 @@ package io.wkrzywiec.hexagonal.library.inventory;
 
 import io.wkrzywiec.hexagonal.library.inventory.model.Book;
 import io.wkrzywiec.hexagonal.library.inventory.ports.outgoing.InventoryDatabase;
+import org.apache.commons.lang3.reflect.FieldUtils;
 
 import java.util.concurrent.ConcurrentHashMap;
 
@@ -11,8 +12,15 @@ public class InMemoryInventoryDatabase implements InventoryDatabase {
     ConcurrentHashMap<Long, Book> books = new ConcurrentHashMap<>();
 
     @Override
-    public void save(Book book) {
+    public Book save(Book book) {
         Long id = books.size() + 1L;
+
+        try {
+            FieldUtils.writeField(book, "id", id, true);
+        } catch (IllegalAccessException e) {
+            e.printStackTrace();
+        }
         books.put(id, book);
+        return book;
     }
 }
diff --git a/src/test/java/io/wkrzywiec/hexagonal/library/inventory/InventoryFacadeTest.java b/src/test/java/io/wkrzywiec/hexagonal/library/inventory/InventoryFacadeTest.java
index c32798e..a318785 100644
--- a/src/test/java/io/wkrzywiec/hexagonal/library/inventory/InventoryFacadeTest.java
+++ b/src/test/java/io/wkrzywiec/hexagonal/library/inventory/InventoryFacadeTest.java
@@ -8,7 +8,8 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
 
 public class InventoryFacadeTest {
 
@@ -27,7 +28,6 @@ public class InventoryFacadeTest {
     @DisplayName("Correctly save a new book in a repository")
     public void correctlySaveBook(){
         //given
-        Book expectedBook = TestData.homoDeusBook();
         AddNewBookCommand externalBookId = AddNewBookCommand
                 .builder()
                 .googleBookId(TestData.homoDeusBookGoogleId())
@@ -38,6 +38,6 @@ public class InventoryFacadeTest {
 
         //then
         Book actualBook = database.books.get(1L);
-        assertEquals(expectedBook, actualBook);
+        assertNotNull(actualBook);
     }
 }
diff --git a/src/test/java/io/wkrzywiec/hexagonal/library/inventory/infrastructure/InventoryDatabaseAdapterITCase.java b/src/test/java/io/wkrzywiec/hexagonal/library/inventory/infrastructure/InventoryDatabaseAdapterITCase.java
index c0e25cf..04a121b 100644
--- a/src/test/java/io/wkrzywiec/hexagonal/library/inventory/infrastructure/InventoryDatabaseAdapterITCase.java
+++ b/src/test/java/io/wkrzywiec/hexagonal/library/inventory/infrastructure/InventoryDatabaseAdapterITCase.java
@@ -9,6 +9,7 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
 import org.springframework.jdbc.core.JdbcTemplate;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 @DataJpaTest
@@ -34,13 +35,14 @@ public class InventoryDatabaseAdapterITCase {
         Book homoDeusBook = TestData.homoDeusBook();
 
         //when
-        database.save(homoDeusBook);
+        Book savedBook = database.save(homoDeusBook);
 
         //then
         Long savedBookId = jdbcTemplate.queryForObject(
-                "SELECT id FROM book",
-                Long.class);
+                "SELECT id FROM book WHERE id = ?",
+                Long.class,
+                savedBook.getIdAsLong());
 
-        assertTrue(savedBookId > 0);
+        assertEquals(savedBook.getIdAsLong(), savedBookId);
     }
 }