Implement event domain model and application service

Add Event entity, CreateEventCommand, ports (CreateEventUseCase,
EventRepository), and EventService with Clock injection for
deterministic testing. Expiry date must be in the future.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/src/test/java/de/fete/application/service/EventServiceTest.java

@@ -0,0 +1,140 @@
+package de.fete.application.service;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import de.fete.domain.model.CreateEventCommand;
+import de.fete.domain.model.Event;
+import de.fete.domain.port.out.EventRepository;
+import java.time.Clock;
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.OffsetDateTime;
+import java.time.ZoneId;
+import java.time.ZoneOffset;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+@ExtendWith(MockitoExtension.class)
+class EventServiceTest {
+
+  private static final ZoneId ZONE = ZoneId.of("Europe/Berlin");
+  private static final Instant FIXED_INSTANT =
+      LocalDate.of(2026, 3, 5).atStartOfDay(ZONE).toInstant();
+  private static final Clock FIXED_CLOCK = Clock.fixed(FIXED_INSTANT, ZONE);
+
+  @Mock
+  private EventRepository eventRepository;
+
+  private EventService eventService;
+
+  @BeforeEach
+  void setUp() {
+    eventService = new EventService(eventRepository, FIXED_CLOCK);
+  }
+
+  @Test
+  void createEventWithValidCommand() {
+    when(eventRepository.save(any(Event.class)))
+        .thenAnswer(invocation -> invocation.getArgument(0));
+
+    var command = new CreateEventCommand(
+        "Birthday Party",
+        "Come celebrate!",
+        OffsetDateTime.of(2026, 6, 15, 20, 0, 0, 0, ZoneOffset.ofHours(2)),
+        "Berlin",
+        LocalDate.of(2026, 7, 15)
+    );
+
+    Event result = eventService.createEvent(command);
+
+    assertThat(result.getTitle()).isEqualTo("Birthday Party");
+    assertThat(result.getDescription()).isEqualTo("Come celebrate!");
+    assertThat(result.getLocation()).isEqualTo("Berlin");
+    assertThat(result.getEventToken()).isNotNull();
+    assertThat(result.getOrganizerToken()).isNotNull();
+    assertThat(result.getCreatedAt()).isEqualTo(OffsetDateTime.now(FIXED_CLOCK));
+  }
+
+  @Test
+  void eventTokenAndOrganizerTokenAreDifferent() {
+    when(eventRepository.save(any(Event.class)))
+        .thenAnswer(invocation -> invocation.getArgument(0));
+
+    var command = new CreateEventCommand(
+        "Test", null,
+        OffsetDateTime.now(FIXED_CLOCK).plusDays(1), null,
+        LocalDate.now(FIXED_CLOCK).plusDays(30)
+    );
+
+    Event result = eventService.createEvent(command);
+
+    assertThat(result.getEventToken()).isNotEqualTo(result.getOrganizerToken());
+  }
+
+  @Test
+  void repositorySaveCalledExactlyOnce() {
+    when(eventRepository.save(any(Event.class)))
+        .thenAnswer(invocation -> invocation.getArgument(0));
+
+    var command = new CreateEventCommand(
+        "Test", null,
+        OffsetDateTime.now(FIXED_CLOCK).plusDays(1), null,
+        LocalDate.now(FIXED_CLOCK).plusDays(30)
+    );
+
+    eventService.createEvent(command);
+
+    ArgumentCaptor<Event> captor = ArgumentCaptor.forClass(Event.class);
+    verify(eventRepository, times(1)).save(captor.capture());
+    assertThat(captor.getValue().getTitle()).isEqualTo("Test");
+  }
+
+  @Test
+  void expiryDateTodayThrowsException() {
+    var command = new CreateEventCommand(
+        "Test", null,
+        OffsetDateTime.now(FIXED_CLOCK).plusDays(1), null,
+        LocalDate.now(FIXED_CLOCK)
+    );
+
+    assertThatThrownBy(() -> eventService.createEvent(command))
+        .isInstanceOf(ExpiryDateInPastException.class);
+  }
+
+  @Test
+  void expiryDateInPastThrowsException() {
+    var command = new CreateEventCommand(
+        "Test", null,
+        OffsetDateTime.now(FIXED_CLOCK).plusDays(1), null,
+        LocalDate.now(FIXED_CLOCK).minusDays(5)
+    );
+
+    assertThatThrownBy(() -> eventService.createEvent(command))
+        .isInstanceOf(ExpiryDateInPastException.class);
+  }
+
+  @Test
+  void expiryDateTomorrowSucceeds() {
+    when(eventRepository.save(any(Event.class)))
+        .thenAnswer(invocation -> invocation.getArgument(0));
+
+    var command = new CreateEventCommand(
+        "Test", null,
+        OffsetDateTime.now(FIXED_CLOCK).plusDays(1), null,
+        LocalDate.now(FIXED_CLOCK).plusDays(1)
+    );
+
+    Event result = eventService.createEvent(command);
+
+    assertThat(result.getExpiryDate()).isEqualTo(LocalDate.of(2026, 3, 6));
+  }
+}

backend/src/test/java/de/fete/config/WebConfigTest.java

@@ -29,8 +29,8 @@ class WebConfigTest {
 
   @Test
   void apiPrefixNotAccessibleWithoutIt() throws Exception {
-    // /health without /api prefix should not resolve to the API endpoint
-    mockMvc.perform(get("/health"))
+    // /events without /api prefix should not resolve to the API endpoint
+    mockMvc.perform(get("/events"))
         .andExpect(status().isNotFound());
   }
 }