R62 Fix A1-A6：请假预览全非工作日处理

server/tests/unit/routes/leave.working-days.test.js

@@ -136,6 +136,7 @@ describe("leave working-days route", () => {
       weekendDayCount: 0,
       adjustedWorkdayCount: 1,
       calendarApplied: true,
+      isNonWorkingRange: false,
     });
 
     await app.close();
@@ -158,6 +159,44 @@ describe("leave working-days route", () => {
       weekendDayCount: 0,
       adjustedWorkdayCount: 0.5,
       calendarApplied: true,
+      isNonWorkingRange: false,
+    });
+
+    await app.close();
+  });
+
+  it("returns zero days instead of error for fully non-working preview ranges", async () => {
+    const { app } = await buildApp({
+      legalEntity: buildLegalEntity({
+        default_holiday_calendar: {
+          id: "calendar-1",
+          archived_at: null,
+          days: [
+            buildCalendarDay("2026-05-01", "holiday"),
+            buildCalendarDay("2026-05-02", "holiday"),
+            buildCalendarDay("2026-05-03", "holiday"),
+            buildCalendarDay("2026-05-04", "holiday"),
+            buildCalendarDay("2026-05-05", "holiday"),
+          ],
+        },
+      }),
+    });
+
+    const response = await app.inject({
+      method: "GET",
+      url: "/api/leave-requests/working-days?startDate=2026-05-01&endDate=2026-05-05&startSession=am&endSession=pm",
+      headers: { authorization: "Bearer test" },
+    });
+
+    expect(response.statusCode).toBe(200);
+    expect(response.json().data).toEqual({
+      requestedDays: 0,
+      naturalRequestedDays: 5,
+      holidayDayCount: 5,
+      weekendDayCount: 0,
+      adjustedWorkdayCount: 0,
+      calendarApplied: true,
+      isNonWorkingRange: true,
     });
 
     await app.close();
@@ -182,6 +221,7 @@ describe("leave working-days route", () => {
       weekendDayCount: 0,
       adjustedWorkdayCount: 0,
       calendarApplied: false,
+      isNonWorkingRange: false,
     });
     expect(featureFlagFindUnique).not.toHaveBeenCalled();
     expect(legalEntityFindUnique).not.toHaveBeenCalled();