refactor(backend): update expense claims service and tests

- services/expense_claims.py: update expense claims service
- tests/test_expense_claim_service.py: update expense claim service tests

server/src/app/services/expense_claims.py

@@ -535,7 +535,6 @@ class ExpenseClaimService:
         if is_new_claim:
             existing_draft_count = self._count_draft_claims_for_owner(
                 employee=employee,
-                employee_name=draft_owner_name,
                 user_id=user_id,
             )
             if existing_draft_count >= MAX_DRAFT_CLAIMS_PER_USER:
@@ -733,12 +732,10 @@ class ExpenseClaimService:
         self,
         *,
         employee: Employee | None,
-        employee_name: str,
         user_id: str | None,
     ) -> int:
         owner_filters = self._build_draft_owner_filters(
             employee=employee,
-            employee_name=employee_name,
             user_id=user_id,
         )
         if not owner_filters:
@@ -752,11 +749,10 @@ class ExpenseClaimService:
         )
         return int(self.db.scalar(stmt) or 0)
 
-    @staticmethod
     def _build_draft_owner_filters(
+        self,
         *,
         employee: Employee | None,
-        employee_name: str,
         user_id: str | None,
     ) -> list[Any]:
         conditions: list[Any] = []
@@ -779,10 +775,10 @@ class ExpenseClaimService:
 
         if employee is not None:
             add_condition("employee_id", employee.id)
-            add_condition("employee_name", employee.name)
             add_condition("employee_name", employee.email)
+            if self._employee_name_is_unique(employee):
+                add_condition("employee_name", employee.name)
 
-        add_condition("employee_name", employee_name)
         add_condition("employee_name", user_id)
         return conditions
 
@@ -1607,7 +1603,25 @@ class ExpenseClaimService:
 
     @staticmethod
     def _has_privileged_claim_access(current_user: CurrentUserContext) -> bool:
-        return bool(set(current_user.role_codes) & PRIVILEGED_CLAIM_ROLE_CODES)
+        role_codes = {
+            str(item).strip().lower()
+            for item in current_user.role_codes
+            if str(item).strip()
+        }
+        return bool(role_codes & PRIVILEGED_CLAIM_ROLE_CODES)
+
+    def _employee_name_is_unique(self, employee: Employee) -> bool:
+        normalized_name = str(employee.name or "").strip()
+        if not normalized_name:
+            return False
+
+        same_name_count = int(
+            self.db.scalar(
+                select(func.count()).select_from(Employee).where(Employee.name == normalized_name)
+            )
+            or 0
+        )
+        return same_name_count == 1
 
     def _apply_claim_scope(self, stmt: Any, current_user: CurrentUserContext) -> Any:
         if self._has_privileged_claim_access(current_user):
@@ -1635,8 +1649,9 @@ class ExpenseClaimService:
 
         if employee is not None:
             add_condition("employee_id", employee.id)
-            add_condition("employee_name", employee.name)
             add_condition("employee_name", employee.email)
+            if self._employee_name_is_unique(employee):
+                add_condition("employee_name", employee.name)
         else:
             add_condition("employee_id", username)
             add_condition("employee_name", username)