diff --git a/client/src/components/PDF/TripPDF.tsx b/client/src/components/PDF/TripPDF.tsx
index 83608b1ea..a4691f793 100644
--- a/client/src/components/PDF/TripPDF.tsx
+++ b/client/src/components/PDF/TripPDF.tsx
@@ -8,6 +8,7 @@ import type { Trip, Day, Place, Category, AssignmentsMap, DayNote, DistanceUnit,
 import { isDayInAccommodationRange, getDayOrder } from '../../utils/dayOrder'
 import { hidesOnMiddleDay, getTransportForDay, getMergedItems, getSpanPhase, getDisplayTimeForDay } from '../../utils/dayMerge'
 import { safeHexColor } from '../../utils/safeColor'
+import { pdfSwitchOn, rememberPdfSwitch } from '../../utils/pdfSwitch'
 import { renderIconMarkup } from '../../utils/iconMarkup'
 import { formatMoney, formatMoneySum, formatClockTime, splitReservationDateTime, type MoneyEntry } from '../../utils/formatters'
 import { useSettingsStore } from '../../store/settingsStore'
@@ -38,23 +39,6 @@ const PAGE_BREAK_KEY = 'trek_pdf_page_break_per_day'
  */
 const TRANSPORT_NOTES_KEY = 'trek_pdf_transport_notes'
 
-/** A preview switch that is on unless it was turned off; both default to on. */
-function pdfSwitchOn(key: string): boolean {
-  try {
-    return localStorage.getItem(key) !== '0'
-  } catch {
-    return true
-  }
-}
-
-function rememberPdfSwitch(key: string, on: boolean): void {
-  try {
-    localStorage.setItem(key, on ? '1' : '0')
-  } catch {
-    // A blocked localStorage costs the preference, not the export.
-  }
-}
-
 /* The overlay is imperative DOM, so the switch from Settings/ToggleSwitch is
    rebuilt here rather than rendered — as static markup it would carry no
    behaviour. Same geometry and the same tokens, so it reads as the same control. */
diff --git a/client/src/utils/pdfSwitch.test.ts b/client/src/utils/pdfSwitch.test.ts
new file mode 100644
index 000000000..09707c99e
--- /dev/null
+++ b/client/src/utils/pdfSwitch.test.ts
@@ -0,0 +1,33 @@
+// FE-UTIL-PDFSWITCH-001 to FE-UTIL-PDFSWITCH-002
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { pdfSwitchOn, rememberPdfSwitch } from './pdfSwitch';
+
+const KEY = 'trek_pdf_test_switch';
+
+afterEach(() => {
+  vi.restoreAllMocks();
+  localStorage.removeItem(KEY);
+});
+
+describe('pdfSwitch', () => {
+  it('FE-UTIL-PDFSWITCH-001: a switch is on until it is turned off, and remembers either way', () => {
+    expect(pdfSwitchOn(KEY)).toBe(true);
+    rememberPdfSwitch(KEY, false);
+    expect(localStorage.getItem(KEY)).toBe('0');
+    expect(pdfSwitchOn(KEY)).toBe(false);
+    rememberPdfSwitch(KEY, true);
+    expect(localStorage.getItem(KEY)).toBe('1');
+    expect(pdfSwitchOn(KEY)).toBe(true);
+  });
+
+  it('FE-UTIL-PDFSWITCH-002: a blocked localStorage reads as on and drops the write without throwing', () => {
+    vi.spyOn(Storage.prototype, 'getItem').mockImplementation(() => {
+      throw new Error('blocked');
+    });
+    vi.spyOn(Storage.prototype, 'setItem').mockImplementation(() => {
+      throw new Error('blocked');
+    });
+    expect(pdfSwitchOn(KEY)).toBe(true);
+    expect(() => rememberPdfSwitch(KEY, false)).not.toThrow();
+  });
+});
diff --git a/client/src/utils/pdfSwitch.ts b/client/src/utils/pdfSwitch.ts
new file mode 100644
index 000000000..2954de87c
--- /dev/null
+++ b/client/src/utils/pdfSwitch.ts
@@ -0,0 +1,21 @@
+/*
+ * The two switches of the trip PDF preview (a new page for every day, and the notes
+ * of the transports), remembered in this browser.
+ */
+
+/** A preview switch that is on unless it was turned off; both default to on. */
+export function pdfSwitchOn(key: string): boolean {
+  try {
+    return localStorage.getItem(key) !== '0';
+  } catch {
+    return true;
+  }
+}
+
+export function rememberPdfSwitch(key: string, on: boolean): void {
+  try {
+    localStorage.setItem(key, on ? '1' : '0');
+  } catch {
+    // A blocked localStorage costs the preference, not the export.
+  }
+}