fix(web): stabilize client file downloads

vehicle-data-platform/apps/web/src/v2/domain/download.test.ts

@@ -0,0 +1,29 @@
+import { afterEach, expect, test, vi } from 'vitest';
+import { DOWNLOAD_URL_REVOKE_MS, downloadBlob } from './download';
+
+afterEach(() => {
+  vi.useRealTimers();
+  vi.restoreAllMocks();
+  document.body.replaceChildren();
+});
+
+test('keeps the blob URL alive through the click and revokes it after cleanup', () => {
+  vi.useFakeTimers();
+  const createObjectURL = vi.spyOn(URL, 'createObjectURL').mockReturnValue('blob:vehicle-export');
+  const revokeObjectURL = vi.spyOn(URL, 'revokeObjectURL').mockImplementation(() => undefined);
+  const click = vi.spyOn(HTMLAnchorElement.prototype, 'click').mockImplementation(function (this: HTMLAnchorElement) {
+    expect(this.isConnected).toBe(true);
+    expect(this.href).toContain('blob:vehicle-export');
+    expect(this.download).toBe('车辆导出.csv');
+    expect(revokeObjectURL).not.toHaveBeenCalled();
+  });
+
+  downloadBlob(new Blob(['vehicle']), '车辆导出.csv');
+
+  expect(createObjectURL).toHaveBeenCalledTimes(1);
+  expect(click).toHaveBeenCalledTimes(1);
+  expect(document.querySelector('a[download]')).toBeNull();
+  expect(revokeObjectURL).not.toHaveBeenCalled();
+  vi.advanceTimersByTime(DOWNLOAD_URL_REVOKE_MS);
+  expect(revokeObjectURL).toHaveBeenCalledWith('blob:vehicle-export');
+});