Expand unit and e2e coverage

e2e/picklist.spec.ts

@@ -32,4 +32,25 @@ test.describe('Active pick list', () => {
     await expect(page.getByText(additionalProduct).first()).toBeVisible();
     await expect(page.getByRole('button', { name: 'Save and Return' })).toBeEnabled();
   });
+
+  test('allows adding and editing products from the manage products screen', async ({ page }) => {
+    await page.goto('/');
+
+    await page.getByRole('link', { name: 'Manage Products' }).click();
+
+    await page.getByLabel('Name').click();
+    await page.getByLabel('Name').fill('Playwright Cola');
+    await page.getByLabel('Category').click();
+    await page.getByRole('option', { name: 'Drinks' }).click();
+    await page.getByRole('button', { name: 'Save Product' }).click();
+
+    await expect(page.getByText('Product added.')).toBeVisible();
+    await expect(page.getByText('Playwright Cola')).toBeVisible();
+
+    await page.getByRole('button', { name: 'Edit Playwright Cola' }).click();
+    await page.getByLabel('Name').nth(1).fill('Playwright Cola Zero');
+    await page.getByRole('button', { name: 'Save product' }).click();
+
+    await expect(page.getByText('Playwright Cola Zero')).toBeVisible();
+  });
 });

src/modules/openFoodFacts.test.ts

@@ -76,5 +76,28 @@ describe('fetchProductFromOFF', () => {
 
     expect(result).toBeNull();
   });
+
+  it('returns null immediately when the barcode is empty', async () => {
+    const result = await fetchProductFromOFF('');
+
+    expect(result).toBeNull();
+  });
+
+  it('returns null when the browser is offline', async () => {
+    const originalNavigator = navigator;
+    Object.defineProperty(globalThis, 'navigator', {
+      value: { onLine: false },
+      configurable: true,
+    });
+
+    const result = await fetchProductFromOFF('123456');
+
+    expect(result).toBeNull();
+
+    Object.defineProperty(globalThis, 'navigator', {
+      value: originalNavigator,
+      configurable: true,
+    });
+  });
 });
 

src/screens/ManageProductsScreen.test.tsx

@@ -165,6 +165,33 @@ describe('ManageProductsScreen barcode lookup', () => {
     expect(mockDb.products.add).not.toHaveBeenCalled();
   });
 
+  it('informs the user when barcode lookup happens offline', async () => {
+    const originalNavigator = navigator;
+    Object.defineProperty(globalThis, 'navigator', {
+      value: { onLine: false },
+      configurable: true,
+    });
+
+    try {
+      const user = userEvent.setup();
+      render(
+        <MemoryRouter>
+          <ManageProductsScreen />
+        </MemoryRouter>,
+      );
+
+      await user.click(screen.getByRole('button', { name: /scan barcode/i }));
+      await user.click(screen.getByRole('button', { name: /mock scan/i }));
+
+      expect(await screen.findByText(/you are offline\. enter details manually\./i)).toBeVisible();
+    } finally {
+      Object.defineProperty(globalThis, 'navigator', {
+        value: originalNavigator,
+        configurable: true,
+      });
+    }
+  });
+
   it('prevents updating a product to use an existing barcode', async () => {
     mockUseProducts.mockReturnValue([
       {