test(invites): add InviteTokenRepository integration tests for existsActiveWithGroupId + V66 group_id index

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

backend/src/main/resources/db/migration/V66__add_invite_token_group_id_index.sql

@@ -0,0 +1,3 @@
+-- The composite PK (invite_token_id, group_id) does not support efficient lookups by group_id alone.
+-- Add a dedicated index to support existsActiveWithGroupId queries.
+CREATE INDEX idx_itg_group_id ON invite_token_group_ids (group_id);

backend/src/test/java/org/raddatz/familienarchiv/user/InviteTokenRepositoryIntegrationTest.java

@@ -0,0 +1,78 @@
+package org.raddatz.familienarchiv.user;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.raddatz.familienarchiv.PostgresContainerConfig;
+import org.raddatz.familienarchiv.config.FlywayConfig;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.jdbc.test.autoconfigure.AutoConfigureTestDatabase;
+import org.springframework.boot.data.jpa.test.autoconfigure.DataJpaTest;
+import org.springframework.context.annotation.Import;
+
+import java.time.LocalDateTime;
+import java.util.Set;
+import java.util.UUID;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@DataJpaTest
+@AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
+@Import({PostgresContainerConfig.class, FlywayConfig.class})
+class InviteTokenRepositoryIntegrationTest {
+
+    @Autowired InviteTokenRepository inviteTokenRepository;
+    @Autowired UserGroupRepository userGroupRepository;
+    @Autowired AppUserRepository appUserRepository;
+
+    private UserGroup group;
+    private AppUser admin;
+
+    @BeforeEach
+    void setUp() {
+        inviteTokenRepository.deleteAll();
+        userGroupRepository.deleteAll();
+        appUserRepository.deleteAll();
+        admin = appUserRepository.save(AppUser.builder().email("admin@test.com").password("pw").build());
+        group = userGroupRepository.save(UserGroup.builder().name("Familie").build());
+    }
+
+    // ─── existsActiveWithGroupId ──────────────────────────────────────────────
+
+    @Test
+    void existsActiveWithGroupId_returnsTrueForActiveInviteLinkedToGroup() {
+        inviteTokenRepository.save(token(t -> t));
+
+        assertThat(inviteTokenRepository.existsActiveWithGroupId(group.getId())).isTrue();
+    }
+
+    @Test
+    void existsActiveWithGroupId_returnsFalseWhenInviteIsRevoked() {
+        inviteTokenRepository.save(token(t -> t.revoked(true)));
+
+        assertThat(inviteTokenRepository.existsActiveWithGroupId(group.getId())).isFalse();
+    }
+
+    @Test
+    void existsActiveWithGroupId_returnsFalseWhenInviteIsExpired() {
+        inviteTokenRepository.save(token(t -> t.expiresAt(LocalDateTime.now().minusDays(1))));
+
+        assertThat(inviteTokenRepository.existsActiveWithGroupId(group.getId())).isFalse();
+    }
+
+    @Test
+    void existsActiveWithGroupId_returnsFalseWhenInviteIsExhausted() {
+        inviteTokenRepository.save(token(t -> t.maxUses(1).useCount(1)));
+
+        assertThat(inviteTokenRepository.existsActiveWithGroupId(group.getId())).isFalse();
+    }
+
+    // ─── helpers ─────────────────────────────────────────────────────────────
+
+    private InviteToken token(java.util.function.UnaryOperator<InviteToken.InviteTokenBuilder> customizer) {
+        InviteToken.InviteTokenBuilder builder = InviteToken.builder()
+                .code(UUID.randomUUID().toString().replace("-", "").substring(0, 10))
+                .groupIds(new java.util.HashSet<>(Set.of(group.getId())))
+                .createdBy(admin);
+        return customizer.apply(builder).build();
+    }
+}