Prevent deletion of in-use records

src/screens/ManageCategoriesScreen.test.tsx

@@ -0,0 +1,59 @@
+import { MemoryRouter } from 'react-router-dom';
+import { render, screen } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { describe, expect, it, vi } from 'vitest';
+import { ManageCategoriesScreen } from './ManageCategoriesScreen';
+
+const categoriesMock = [{ id: 'cat-1', name: 'Snacks', created_at: 0, updated_at: 0 }];
+const productsMock = [
+  {
+    id: 'prod-1',
+    name: 'Chips',
+    category: 'Snacks',
+    archived: false,
+    created_at: 0,
+    updated_at: 0,
+  },
+];
+
+vi.mock('../hooks/dataHooks', () => ({
+  useCategories: () => categoriesMock,
+  useProducts: () => productsMock,
+}));
+
+const categoryDeleteMock = vi.fn();
+
+vi.mock('../context/DBProvider', () => ({
+  useDatabase: () => ({
+    categories: {
+      add: vi.fn(),
+      update: vi.fn(),
+      delete: categoryDeleteMock,
+    },
+    products: {
+      where: () => ({
+        equals: () => ({
+          modify: vi.fn(),
+        }),
+      }),
+    },
+  }),
+}));
+
+describe('ManageCategoriesScreen deletion safeguards', () => {
+  it('shows an error when trying to delete an in-use category', async () => {
+    const user = userEvent.setup();
+    render(
+      <MemoryRouter>
+        <ManageCategoriesScreen />
+      </MemoryRouter>,
+    );
+
+    await user.click(screen.getByRole('button', { name: /delete snacks/i }));
+
+    expect(categoryDeleteMock).not.toHaveBeenCalled();
+    expect(
+      await screen.findByText(/cannot delete 'snacks' while 1 product\(s\) use it/i),
+    ).toBeVisible();
+  });
+});