diff --git a/pom.xml b/pom.xml
index 543c1aa50..7d8ef717a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -16,19 +16,19 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
-            <version>5.11.4</version>
+            <version>6.0.1</version>
             <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>org.assertj</groupId>
             <artifactId>assertj-core</artifactId>
-            <version>3.27.3</version>
+            <version>3.27.6</version>
             <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-junit-jupiter</artifactId>
-            <version>5.15.2</version>
+            <version>5.21.0</version>
             <scope>test</scope>
         </dependency>
     </dependencies>
diff --git a/src/test/java/com/example/BookingSystemTest.java b/src/test/java/com/example/BookingSystemTest.java
new file mode 100644
index 000000000..c28e209ee
--- /dev/null
+++ b/src/test/java/com/example/BookingSystemTest.java
@@ -0,0 +1,289 @@
+package com.example;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.junit.jupiter.MockitoExtension;
+import java.time.LocalDateTime;
+import java.util.List;
+import java.util.Optional;
+
+import static org.mockito.ArgumentMatchers.any;
+
+@ExtendWith(MockitoExtension.class)
+class BookingSystemTest {
+
+    @Mock
+    private TimeProvider timeProvider;
+
+    @Mock
+    private RoomRepository roomRepository;
+
+    @Mock
+    private NotificationService notificationService;
+
+    @Mock
+    private Room room;
+
+    private BookingSystem bookingSystem;
+
+
+    @Test
+    void bookingSystemTestHappyCase()
+    {
+        //Preconditions
+        room = new Room("101", "101");
+        LocalDateTime start = LocalDateTime.of(2026, 1, 1, 12, 0);
+        LocalDateTime end = start.plusHours(1);
+
+        Mockito.when(timeProvider.getCurrentTime()).thenReturn(start);
+        Mockito.when(roomRepository.findById("101")).thenReturn(Optional.of(room));
+
+        bookingSystem = new BookingSystem(timeProvider, roomRepository, notificationService);
+
+        //Execution
+        bookingSystem.bookRoom("101", start, end);
+    }
+
+    @Test
+    void bookingSystemTestUnhappyCaseStartTimeIsNull(){
+
+        //Preconditions
+
+        bookingSystem = new BookingSystem(timeProvider, roomRepository, notificationService);
+
+        //Execution
+        Assertions.assertThrows(IllegalArgumentException.class, () -> bookingSystem.bookRoom("101", null, LocalDateTime.now()));
+
+    }
+    @Test
+    void bookingSystemTestUnhappyCaseEndTimeIsNull(){
+
+        //Preconditions
+
+        bookingSystem = new BookingSystem(timeProvider, roomRepository, notificationService);
+
+        //Execution
+        Assertions.assertThrows(IllegalArgumentException.class, () -> bookingSystem.bookRoom("101", LocalDateTime.now(), null));
+
+    }
+    @Test
+    void bookingSystemTestUnhappyCaseRoomIsNull(){
+
+        //Preconditions
+
+        bookingSystem = new BookingSystem(timeProvider, roomRepository, notificationService);
+
+        //Execution
+        Assertions.assertThrows(IllegalArgumentException.class, () -> bookingSystem.bookRoom(null, LocalDateTime.now(), LocalDateTime.now().plusHours(1)));
+
+    }
+    @Test
+    void bookingSystemTestUnhappyCaseStartTimeIsBeforeCurrentTime()
+    {
+        LocalDateTime start = LocalDateTime.of(2026, 1, 1, 12, 0);
+        LocalDateTime end = start.plusHours(1);
+        //Preconditions
+        room = new Room("101", "101");
+
+        Mockito.when(timeProvider.getCurrentTime()).thenReturn(start);
+
+        try{
+            bookingSystem = new BookingSystem(timeProvider, roomRepository, notificationService);
+            bookingSystem.bookRoom("101", start.minusHours(1), end);
+        } catch (IllegalArgumentException e) {
+            Assertions.assertEquals(e.getMessage(), "Kan inte boka tid i dåtid");
+        }
+
+
+    }
+    @Test
+    void bookingSystemTestUnhappyCaseEndtimeIsBeforeStartTime()
+    {
+        LocalDateTime start = LocalDateTime.of(2026, 1, 1, 12, 0);
+        LocalDateTime end = start.plusHours(-1);
+        //Preconditions
+        room = new Room("101", "101");
+
+        Mockito.when(timeProvider.getCurrentTime()).thenReturn(start);
+
+        try {
+            bookingSystem = new BookingSystem(timeProvider, roomRepository, notificationService);
+            bookingSystem.bookRoom("101", start, end);
+            //Execution
+
+        } catch (IllegalArgumentException e) {
+            Assertions.assertEquals(e.getMessage(), "Sluttid måste vara efter starttid");
+        }
+    }
+    @Test
+    void bookingSystemTestUnhappyCaseRoomDoesNotExist()
+    {
+        //Preconditions
+
+        Mockito.when(timeProvider.getCurrentTime()).thenReturn(LocalDateTime.now());
+        Mockito.when(roomRepository.findById("101")).thenReturn(Optional.empty());
+
+        bookingSystem = new BookingSystem(timeProvider, roomRepository, notificationService);
+
+        //Execution
+        Assertions.assertThrows(IllegalArgumentException.class, () ->bookingSystem.bookRoom("101", LocalDateTime.now(), LocalDateTime.now().plusHours(1)));
+    }
+    @Test
+    void bookRoom_roomNotAvailable_returnsFalse() {
+
+
+        Mockito.when(timeProvider.getCurrentTime()).thenReturn(LocalDateTime.now());
+
+        Room room = Mockito.mock(Room.class);
+        Mockito.when(roomRepository.findById("101")).thenReturn(Optional.of(room));
+        Mockito.when(room.isAvailable(any(), any())).thenReturn(false);
+
+        BookingSystem bookingSystem =
+                new BookingSystem(timeProvider, roomRepository, notificationService);
+
+
+        boolean result = bookingSystem.bookRoom("101", LocalDateTime.now(), LocalDateTime.now().plusHours(1));
+
+
+        Assertions.assertFalse(result);
+
+    }
+    @Test
+    void bookRoom_roomAvailable_returnsTrue() {
+
+
+        Mockito.when(timeProvider.getCurrentTime()).thenReturn(LocalDateTime.now());
+
+        Room room = Mockito.mock(Room.class);
+        Mockito.when(roomRepository.findById("101")).thenReturn(Optional.of(room));
+        Mockito.when(room.isAvailable(any(), any())).thenReturn(true);
+
+        BookingSystem bookingSystem = new BookingSystem(timeProvider, roomRepository, notificationService);
+
+
+        boolean result = bookingSystem.bookRoom("101", LocalDateTime.now(), LocalDateTime.now().plusHours(1));
+
+
+        Assertions.assertTrue(result);
+    }
+    @Test
+    void getAvailableRooms_startTimeIsNull_throwsException() {
+        LocalDateTime start = null;
+        LocalDateTime end = LocalDateTime.of(2026, 1, 1, 12, 0);
+        try {
+            BookingSystem bookingSystem = new BookingSystem(timeProvider, roomRepository, notificationService);
+            bookingSystem.getAvailableRooms(start, end);
+        }catch (IllegalArgumentException e) {
+            Assertions.assertEquals(e.getMessage(), "Måste ange både start- och sluttid");
+        }
+    }
+    @Test
+    void getAvailableRooms_endTimeIsNull_throwsException() {
+        LocalDateTime start = LocalDateTime.of(2026, 1, 1, 12, 0);
+        LocalDateTime end = null;
+        try {
+            BookingSystem bookingSystem = new BookingSystem(timeProvider, roomRepository, notificationService);
+            bookingSystem.getAvailableRooms(start, end);
+        }catch (IllegalArgumentException e) {
+            Assertions.assertEquals(e.getMessage(), "Måste ange både start- och sluttid");
+        }
+    }
+    @Test
+    void getAvailableRooms_endBeforeStart_throwsException() {
+        LocalDateTime start = LocalDateTime.of(2026, 1, 1, 12, 0);
+        LocalDateTime end = start.plusHours(-1);
+        try {
+            BookingSystem bookingSystem = new BookingSystem(timeProvider, roomRepository, notificationService);
+            bookingSystem.getAvailableRooms(start, end);
+        }catch (IllegalArgumentException e) {
+            Assertions.assertEquals(e.getMessage(), "Sluttid måste vara efter starttid");
+        }
+    }
+    @Test
+    void getAvailableRooms_returnsOnlyRoomsThatAreAvailable() {
+        LocalDateTime start = LocalDateTime.of(2026, 1, 1, 12, 0);
+        LocalDateTime end = start.plusHours(1);
+
+        Room availableRoom = Mockito.mock(Room.class);
+        Room unavailableRoom = Mockito.mock(Room.class);
+
+        Mockito.when(roomRepository.findAll()).thenReturn(List.of(availableRoom, unavailableRoom));
+
+        Mockito.when(availableRoom.isAvailable(start, end)).thenReturn(true);
+        Mockito.when(unavailableRoom.isAvailable(start, end)).thenReturn(false);
+
+        BookingSystem bookingSystem = new BookingSystem(timeProvider, roomRepository, notificationService);
+
+        List<Room> result = bookingSystem.getAvailableRooms(start, end);
+
+        Assertions.assertTrue(result.contains(availableRoom));
+        Assertions.assertFalse(result.contains(unavailableRoom));
+    }
+    @Test
+    void cancelBooking_bookingIdIsNull_throwsException() {
+
+        try {
+            BookingSystem bookingSystem = new BookingSystem(timeProvider, roomRepository, notificationService);
+            bookingSystem.cancelBooking(null);
+        }catch (IllegalArgumentException e) {
+            Assertions.assertEquals(e.getMessage(), "Boknings-id kan inte vara null");
+        }
+    }
+    @Test
+    void cancelBooking_bookingNotFound_returnsFalse() {
+
+        Room room = Mockito.mock(Room.class);
+        Mockito.when(room.hasBooking("1")).thenReturn(false);
+        Mockito.when(roomRepository.findAll()).thenReturn(List.of(room));
+
+        BookingSystem bookingSystem = new BookingSystem(timeProvider, roomRepository, notificationService);
+
+        boolean result = bookingSystem.cancelBooking("1");
+
+        Assertions.assertFalse(result);
+    }
+    @Test
+    void cancelBooking_bookingAlreadyStarted_throwsException(){
+        LocalDateTime start = LocalDateTime.of(2026, 1, 1, 12, 0);
+        Mockito.when(timeProvider.getCurrentTime()).thenReturn(start);
+        Room room = Mockito.mock(Room.class);
+        Booking booking = Mockito.mock(Booking.class);
+        Mockito.when(roomRepository.findAll()).thenReturn(List.of(room));
+        Mockito.when(room.hasBooking("1")).thenReturn(true);
+        Mockito.when(room.getBooking("1")).thenReturn(booking);
+        Mockito.when(booking.getStartTime()).thenReturn(start.plusHours(-1));
+
+        try {
+            BookingSystem bookingSystem = new BookingSystem(timeProvider, roomRepository, notificationService);
+            bookingSystem.cancelBooking("1");
+        }catch (IllegalStateException e) {
+            Assertions.assertEquals(e.getMessage(), "Kan inte avboka påbörjad eller avslutad bokning");
+        }
+
+    }
+    @Test
+    void cancelBooking_success_returnsTrue() {
+        // Arrange
+        LocalDateTime start = LocalDateTime.of(2026, 1, 1, 12, 0);
+        Mockito.when(timeProvider.getCurrentTime()).thenReturn(start);
+        Room room = Mockito.mock(Room.class);
+        Booking booking = Mockito.mock(Booking.class);
+
+        Mockito.when(roomRepository.findAll()).thenReturn(List.of(room));
+        Mockito.when(room.hasBooking("1")).thenReturn(true);
+        Mockito.when(room.getBooking("1")).thenReturn(booking);
+        Mockito.when(booking.getStartTime()).thenReturn(start.plusHours(1));
+
+        BookingSystem bookingSystem = new BookingSystem(timeProvider, roomRepository, notificationService);
+
+        boolean result = bookingSystem.cancelBooking("1");
+
+        Assertions.assertTrue(result);
+    }
+
+
+}
\ No newline at end of file