diff --git a/tests/unit/server/groups-upsert.sync.test.ts b/tests/unit/server/groups-upsert.sync.test.ts
new file mode 100644
index 0000000..df999a1
--- /dev/null
+++ b/tests/unit/server/groups-upsert.sync.test.ts
@@ -0,0 +1,87 @@
+import { describe, test, expect, beforeEach, afterEach } from 'bun:test';
+import { WebhookServer } from '../../../src/server';
+import { GroupSyncService } from '../../../src/services/group-sync';
+import { makeMemDb, injectAllServices, resetServices } from '../../helpers/db';
+import type { Database as SqliteDatabase } from 'bun:sqlite';
+
+describe('WebhookServer - groups.upsert encadena syncGroups y syncMembersForActiveGroups', () => {
+  const envBackup = { ...process.env };
+  let db: SqliteDatabase;
+
+  let originalSyncGroups: any;
+  let originalRefresh: any;
+  let originalSyncMembers: any;
+
+  let calledSyncGroups = 0;
+  let calledRefresh = 0;
+  let calledSyncMembers = 0;
+
+  beforeEach(() => {
+    process.env = {
+      ...envBackup,
+      NODE_ENV: 'production',
+      EVOLUTION_API_INSTANCE: 'inst-1',
+      EVOLUTION_API_URL: 'http://localhost:1234',
+      EVOLUTION_API_KEY: 'dummy',
+      CHATBOT_PHONE_NUMBER: '123456789',
+      WEBHOOK_URL: 'http://localhost:3000/webhook'
+    };
+
+    db = makeMemDb();
+    // Inyectar DB en servicios
+    (WebhookServer as any).dbInstance = db;
+    injectAllServices(db);
+
+    // Guardar originales y stubear
+    originalSyncGroups = GroupSyncService.syncGroups;
+    originalRefresh = GroupSyncService.refreshActiveGroupsCache;
+    originalSyncMembers = GroupSyncService.syncMembersForActiveGroups;
+
+    calledSyncGroups = 0;
+    calledRefresh = 0;
+    calledSyncMembers = 0;
+
+    GroupSyncService.syncGroups = async () => {
+      calledSyncGroups++;
+      return { added: 0, updated: 0 };
+    };
+    GroupSyncService.refreshActiveGroupsCache = () => {
+      calledRefresh++;
+    };
+    GroupSyncService.syncMembersForActiveGroups = async () => {
+      calledSyncMembers++;
+      return { groups: 0, added: 0, updated: 0, deactivated: 0 };
+    };
+  });
+
+  afterEach(async () => {
+    // Restaurar stubs
+    GroupSyncService.syncGroups = originalSyncGroups;
+    GroupSyncService.refreshActiveGroupsCache = originalRefresh;
+    GroupSyncService.syncMembersForActiveGroups = originalSyncMembers;
+
+    resetServices();
+    try { db.close(); } catch {}
+    process.env = envBackup;
+  });
+
+  test('dispara syncGroups -> refreshActiveGroupsCache -> syncMembersForActiveGroups y responde 200', async () => {
+    const payload = {
+      event: 'groups.upsert',
+      instance: 'inst-1',
+      data: { any: 'thing' }
+    };
+
+    const req = new Request('http://localhost/webhook', {
+      method: 'POST',
+      headers: { 'content-type': 'application/json' },
+      body: JSON.stringify(payload)
+    });
+
+    const res = await WebhookServer.handleRequest(req);
+    expect(res.status).toBe(200);
+    expect(calledSyncGroups).toBe(1);
+    expect(calledRefresh).toBe(1);
+    expect(calledSyncMembers).toBe(1);
+  });
+});
diff --git a/tests/unit/services/group-sync.coverage.test.ts b/tests/unit/services/group-sync.coverage.test.ts
new file mode 100644
index 0000000..2629676
--- /dev/null
+++ b/tests/unit/services/group-sync.coverage.test.ts
@@ -0,0 +1,53 @@
+import { describe, test, expect, beforeEach, afterEach } from 'bun:test';
+import type { Database as SqliteDatabase } from 'bun:sqlite';
+import { makeMemDb, injectAllServices, resetServices } from '../../helpers/db';
+import { GroupSyncService } from '../../../src/services/group-sync';
+import { IdentityService } from '../../../src/services/identity';
+import { Metrics } from '../../../src/services/metrics';
+
+describe('GroupSyncService - alias_coverage_ratio', () => {
+  const envBackup = { ...process.env };
+  let db: SqliteDatabase;
+
+  beforeEach(() => {
+    process.env = { ...envBackup, NODE_ENV: 'test', METRICS_ENABLED: 'true' };
+    Metrics.reset();
+    db = makeMemDb();
+    injectAllServices(db);
+    (GroupSyncService as any).dbInstance = db;
+    (IdentityService as any).dbInstance = db;
+
+    // Crear grupo activo requerido por FK
+    db.prepare(`INSERT INTO groups (id, community_id, name, active) VALUES (?, ?, ?, 1)`)
+      .run('g1@g.us', 'comm-1', 'G1');
+  });
+
+  afterEach(() => {
+    resetServices();
+    try { db.close(); } catch {}
+    Metrics.reset();
+    process.env = envBackup;
+    try { (IdentityService as any).inMemoryAliases?.clear?.(); } catch {}
+  });
+
+  test('calcula cobertura en función de dígitos y alias resolubles', () => {
+    // Sembrar un alias resoluble: aliasB -> 222
+    IdentityService.upsertAlias('aliasB', '222', 'test');
+
+    // Reconciliar miembros: 111 (dígitos), aliasA (no resoluble), aliasB (resoluble a 222)
+    GroupSyncService.reconcileGroupMembers('g1@g.us', [
+      { userId: '111', isAdmin: false },
+      { userId: 'aliasA', isAdmin: false },
+      { userId: 'aliasB', isAdmin: false },
+    ], '2025-01-01 00:00:00.000');
+
+    const json = JSON.parse(Metrics.render('json'));
+    const key = 'group_id="g1@g.us"';
+    const ratio = json?.labeledGauges?.alias_coverage_ratio?.[key];
+
+    expect(typeof ratio).toBe('number');
+    // 2 resolubles (111 y aliasB) de 3 totales -> 0.666...
+    expect(ratio).toBeGreaterThan(0.66 - 1e-6);
+    expect(ratio).toBeLessThan(0.67 + 1e-6);
+  });
+});