fix: handle duplicate usernames and failed role lookups in importDingTalkUsers

apps/server/src/sync/sync.service.spec.ts

@@ -116,13 +116,17 @@ describe('SyncService — new methods', () => {
     );
   });
 
-  it('imports teacher when roleId is a number but role not found (logs warning, no roles assigned)', async () => {
+  it('imports teacher when roleId is a number but role not found (creates student as fallback)', async () => {
     roleRepo.findOne.mockResolvedValue(null);
 
     const mockUser = { id: 11 } as User;
     userRepo.create.mockReturnValue(mockUser);
     userRepo.save.mockResolvedValue(mockUser);
 
+    const mockStudent = { id: 31 } as Student;
+    studentRepo.create.mockReturnValue(mockStudent);
+    studentRepo.save.mockResolvedValue(mockStudent);
+
     mappingRepo.findOne.mockResolvedValue(null);
     mappingRepo.create.mockReturnValue({} as UserDingMapping);
     mappingRepo.save.mockResolvedValue({} as UserDingMapping);
@@ -133,12 +137,21 @@ describe('SyncService — new methods', () => {
 
     const result = await service.importDingTalkUsers(users);
 
-    expect(result.teacherCount).toBe(1);
-    expect(result.studentCount).toBe(0);
+    expect(result.teacherCount).toBe(0);
+    expect(result.studentCount).toBe(1);
     expect(result.skipped).toBe(0);
 
-    // User should be saved once (without roles assignment the second time)
+    // User should be saved once (no second save for role assignment)
     expect(userRepo.save).toHaveBeenCalledTimes(1);
+    // Student record should have been created as fallback
+    expect(studentRepo.create).toHaveBeenCalledWith(
+      expect.objectContaining({
+        name: 'Li Si',
+        userId: 11,
+        status: 'active',
+      }),
+    );
+    expect(studentRepo.save).toHaveBeenCalled();
   });
 
   it('imports student when roleId is null', async () => {