Add tests and utilities for coverage improvements

src/components/__tests__/ProductRow.errors.test.tsx

@@ -0,0 +1,103 @@
+import { render, screen, waitFor } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { describe, expect, it, vi, beforeEach } from 'vitest';
+import { ProductRow } from '../ProductRow';
+import { makeNamedError } from '../../test/makeNamedError';
+
+vi.mock('../BarcodeScannerView', () => ({
+  BarcodeScannerView: ({ onDetected }: { onDetected?: (code: string) => void }) => (
+    <button type="button" onClick={() => onDetected?.('scanned-code')}>
+      Mock Scan
+    </button>
+  ),
+}));
+
+const categories = ['Snacks', 'Drinks'];
+const categoriesById = new Map([
+  ['cat-1', 'Snacks'],
+  ['cat-2', 'Drinks'],
+]);
+
+const baseProduct = {
+  id: 'p1',
+  name: 'Product One',
+  category: 'cat-1',
+  unit_type: 'unit',
+  bulk_name: 'carton',
+  archived: false,
+  created_at: 0,
+  updated_at: 0,
+};
+
+describe('ProductRow error handling', () => {
+  let onSave: ReturnType<typeof vi.fn>;
+  let onDelete: ReturnType<typeof vi.fn>;
+
+  beforeEach(() => {
+    onSave = vi.fn();
+    onDelete = vi.fn();
+  });
+
+  const renderRow = (productOverrides: Partial<typeof baseProduct> = {}) =>
+    render(
+      <ProductRow
+        product={{ ...baseProduct, ...productOverrides }}
+        categories={categories}
+        categoriesById={categoriesById}
+        onSave={onSave}
+        onDelete={onDelete}
+      />,
+    );
+
+  it('shows helper text when onSave throws DuplicateNameError', async () => {
+    const user = userEvent.setup();
+    onSave.mockRejectedValue(makeNamedError('DuplicateNameError'));
+
+    renderRow();
+    await user.click(screen.getByLabelText(/edit product one/i));
+    await user.clear(screen.getByLabelText(/name/i));
+    await user.type(screen.getByLabelText(/name/i), 'Updated');
+    await user.click(screen.getByLabelText(/save product/i));
+
+    await waitFor(() => {
+      expect(screen.getByText('A product with this name already exists.')).toBeInTheDocument();
+    });
+  });
+
+  it('shows barcode helper text when onSave throws DuplicateBarcodeError', async () => {
+    const user = userEvent.setup();
+    onSave.mockRejectedValue(makeNamedError('DuplicateBarcodeError'));
+
+    renderRow({ barcode: '123' });
+    await user.click(screen.getByLabelText(/edit product one/i));
+    await user.type(screen.getByLabelText(/barcode/i), '456');
+    await user.click(screen.getByLabelText(/save product/i));
+
+    await waitFor(() => {
+      expect(screen.getByText('This barcode is already assigned to another product.')).toBeInTheDocument();
+    });
+  });
+
+  it('clears barcode input and toggles scanner dialog visibility', async () => {
+    const user = userEvent.setup();
+
+    renderRow({ barcode: 'abc-123' });
+    await user.click(screen.getByLabelText(/edit product one/i));
+
+    const barcodeField = screen.getByLabelText(/barcode/i);
+    expect(barcodeField).toHaveValue('abc-123');
+
+    await user.click(screen.getByRole('button', { name: /clear/i }));
+    expect(barcodeField).toHaveValue('');
+    expect(screen.queryByText(/barcode/i, { selector: '.MuiFormHelperText-root' })).not.toBeInTheDocument();
+
+    // When barcode is empty, scanner button is shown and opens dialog
+    await user.click(screen.getByLabelText(/cancel edit/i));
+    await user.click(screen.getByLabelText(/edit product one/i));
+    await waitFor(() => expect(screen.getByRole('button', { name: /scan barcode/i })).toBeInTheDocument());
+    await user.click(screen.getByRole('button', { name: /scan barcode/i }));
+    expect(screen.getByRole('dialog', { name: /scan barcode/i })).toBeInTheDocument();
+    await user.click(screen.getByText(/mock scan/i));
+    await waitFor(() => expect(screen.queryByRole('dialog', { name: /scan barcode/i })).not.toBeInTheDocument());
+  });
+});