diff --git a/src/components/BarcodeScannerView.test.tsx b/src/components/BarcodeScannerView.test.tsx
new file mode 100644
index 0000000..d14f2fb
--- /dev/null
+++ b/src/components/BarcodeScannerView.test.tsx
@@ -0,0 +1,40 @@
+import React from 'react';
+import { render, screen } from '@testing-library/react';
+import { describe, expect, it, vi } from 'vitest';
+import { BarcodeScannerView } from './BarcodeScannerView';
+
+const mockUseBarcodeScanner = vi.fn();
+
+vi.mock('../hooks/useBarcodeScanner', () => ({
+  useBarcodeScanner: () => mockUseBarcodeScanner(),
+}));
+
+describe('BarcodeScannerView', () => {
+  it('notifies when a barcode is detected and shows success alert', () => {
+    const onDetected = vi.fn();
+    const videoRef = { current: document.createElement('video') } as React.RefObject<HTMLVideoElement>;
+
+    mockUseBarcodeScanner.mockReturnValue({
+      videoRef,
+      result: { code: '12345', error: null },
+    });
+
+    render(<BarcodeScannerView onDetected={onDetected} />);
+
+    expect(screen.getByText(/detected 12345/i)).toBeVisible();
+    expect(onDetected).toHaveBeenCalledWith('12345');
+  });
+
+  it('renders an error alert when scanning fails', () => {
+    const videoRef = { current: document.createElement('video') } as React.RefObject<HTMLVideoElement>;
+
+    mockUseBarcodeScanner.mockReturnValue({
+      videoRef,
+      result: { code: '', error: 'Camera access denied' },
+    });
+
+    render(<BarcodeScannerView />);
+
+    expect(screen.getByText(/camera access denied/i)).toBeVisible();
+  });
+});
diff --git a/src/components/PickItemRow.test.tsx b/src/components/PickItemRow.test.tsx
index cb3e2d3..7708048 100644
--- a/src/components/PickItemRow.test.tsx
+++ b/src/components/PickItemRow.test.tsx
@@ -145,4 +145,54 @@ describe('PickItemRow', () => {
 
     expect(screen.getByRole('dialog', { name: baseProduct.name })).toBeVisible();
   });
+
+  it('uses inline controls on wide screens', async () => {
+    const onIncrement = vi.fn();
+    const onDecrement = vi.fn();
+    const onToggleCarton = vi.fn();
+    const user = userEvent.setup();
+
+    render(
+      <PickItemRow
+        item={baseItem}
+        product={baseProduct}
+        onIncrementQuantity={onIncrement}
+        onDecrementQuantity={onDecrement}
+        onToggleCarton={onToggleCarton}
+        onStatusChange={vi.fn()}
+        onDelete={vi.fn()}
+      />,
+    );
+
+    await user.click(screen.getByRole('button', { name: /switch to carton packaging/i }));
+    await user.click(screen.getByRole('button', { name: /increase quantity/i }));
+    await user.click(screen.getByRole('button', { name: /decrease quantity/i }));
+
+    expect(onToggleCarton).toHaveBeenCalledTimes(1);
+    expect(onIncrement).toHaveBeenCalledTimes(1);
+    expect(onDecrement).toHaveBeenCalledTimes(1);
+  });
+
+  it('opens controls from keyboard interaction on narrow screens', async () => {
+    mockMatchMedia(true);
+    const user = userEvent.setup();
+
+    render(
+      <PickItemRow
+        item={baseItem}
+        product={baseProduct}
+        onIncrementQuantity={vi.fn()}
+        onDecrementQuantity={vi.fn()}
+        onToggleCarton={vi.fn()}
+        onStatusChange={vi.fn()}
+        onDelete={vi.fn()}
+      />,
+    );
+
+    const row = screen.getByRole('button', { name: /test product/i });
+    row.focus();
+    await user.keyboard('{Enter}');
+
+    expect(screen.getByRole('dialog', { name: baseProduct.name })).toBeVisible();
+  });
 });
diff --git a/src/components/ProductRow.test.tsx b/src/components/ProductRow.test.tsx
index c0bee20..1d87807 100644
--- a/src/components/ProductRow.test.tsx
+++ b/src/components/ProductRow.test.tsx
@@ -1,4 +1,5 @@
 import { render, screen } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
 import { describe, expect, it, vi } from 'vitest';
 import { ProductRow } from './ProductRow';
 import { Product } from '../models/Product';
@@ -32,4 +33,62 @@ describe('ProductRow', () => {
     expect(screen.getByText(/Barcode: 123456/)).toBeInTheDocument();
     expect(screen.queryByText(/bottle/i)).not.toBeInTheDocument();
   });
+
+  it('saves edits and closes the form', async () => {
+    const user = userEvent.setup();
+    const onSave = vi.fn();
+
+    render(
+      <ProductRow product={product} categories={categories} onSave={onSave} onDelete={vi.fn()} />,
+    );
+
+    await user.click(screen.getByLabelText(/edit sparkling water/i));
+    await user.clear(screen.getByLabelText(/name/i));
+    await user.type(screen.getByLabelText(/name/i), 'Still Water');
+    await user.click(screen.getByLabelText(/category/i));
+    await user.selectOptions(screen.getByLabelText(/category/i), 'Snacks');
+    await user.click(screen.getByLabelText(/save product/i));
+
+    expect(onSave).toHaveBeenCalledWith('prod-1', {
+      name: 'Still Water',
+      category: 'Snacks',
+      barcode: '123456',
+    });
+    expect(screen.queryByLabelText(/save product/i)).not.toBeInTheDocument();
+  });
+
+  it('surfaces validation errors from duplicate constraints', async () => {
+    const user = userEvent.setup();
+    const onSave = vi.fn().mockRejectedValueOnce(Object.assign(new Error('dup'), { name: 'DuplicateNameError' }))
+      .mockRejectedValueOnce(Object.assign(new Error('dup'), { name: 'DuplicateBarcodeError' }));
+
+    render(
+      <ProductRow product={product} categories={categories} onSave={onSave} onDelete={vi.fn()} />,
+    );
+
+    await user.click(screen.getByLabelText(/edit sparkling water/i));
+    await user.clear(screen.getByLabelText(/name/i));
+    await user.type(screen.getByLabelText(/name/i), 'Sparkling Water');
+    await user.click(screen.getByLabelText(/save product/i));
+
+    expect(await screen.findByText(/already exists/i)).toBeVisible();
+
+    await user.type(screen.getByLabelText(/barcode/i), '999');
+    await user.click(screen.getByLabelText(/save product/i));
+
+    expect(await screen.findByText(/already assigned/i)).toBeVisible();
+  });
+
+  it('allows clearing and scanning a new barcode', async () => {
+    const user = userEvent.setup();
+
+    render(
+      <ProductRow product={product} categories={categories} onSave={vi.fn()} onDelete={vi.fn()} />,
+    );
+
+    await user.click(screen.getByLabelText(/edit sparkling water/i));
+    await user.click(screen.getByRole('button', { name: /clear/i }));
+
+    expect(screen.getByRole('button', { name: /scan barcode/i })).toBeVisible();
+  });
 });
diff --git a/src/screens/ManageAreasScreen.test.tsx b/src/screens/ManageAreasScreen.test.tsx
index d9689d1..e1ed354 100644
--- a/src/screens/ManageAreasScreen.test.tsx
+++ b/src/screens/ManageAreasScreen.test.tsx
@@ -11,13 +11,15 @@ vi.mock('../hooks/dataHooks', () => ({
 }));
 
 const areaDeleteMock = vi.fn();
+const areaAddMock = vi.fn();
+const areaUpdateMock = vi.fn();
 const pickListCountMock = vi.fn();
 
 vi.mock('../context/DBProvider', () => ({
   useDatabase: () => ({
     areas: {
-      add: vi.fn(),
-      update: vi.fn(),
+      add: areaAddMock,
+      update: areaUpdateMock,
       delete: areaDeleteMock,
     },
     pickLists: {
@@ -48,4 +50,43 @@ describe('ManageAreasScreen deletion safeguards', () => {
       await screen.findByText(/cannot delete this area while 1 pick list\(s\) use it/i),
     ).toBeVisible();
   });
+
+  it('adds a new area and clears the input', async () => {
+    pickListCountMock.mockResolvedValue(0);
+    const user = userEvent.setup();
+
+    render(
+      <MemoryRouter>
+        <ManageAreasScreen />
+      </MemoryRouter>,
+    );
+
+    const nameField = screen.getByLabelText(/area name/i);
+    await user.type(nameField, 'Bakery');
+    await user.click(screen.getByRole('button', { name: /add/i }));
+
+    expect(areaAddMock).toHaveBeenCalledTimes(1);
+    expect((areaAddMock.mock.calls[0][0] as { name: string }).name).toBe('Bakery');
+    expect((nameField as HTMLInputElement).value).toBe('');
+  });
+
+  it('updates an area name and shows feedback', async () => {
+    pickListCountMock.mockResolvedValue(0);
+    const user = userEvent.setup();
+
+    render(
+      <MemoryRouter>
+        <ManageAreasScreen />
+      </MemoryRouter>,
+    );
+
+    await user.click(screen.getByRole('button', { name: /edit front counter/i }));
+    const editField = screen.getByDisplayValue(/front counter/i);
+    await user.clear(editField);
+    await user.type(editField, 'Updated Front');
+    await user.click(screen.getByRole('button', { name: /save area/i }));
+
+    expect(areaUpdateMock).toHaveBeenCalledWith('area-1', expect.objectContaining({ name: 'Updated Front' }));
+    expect(await screen.findByText(/area updated/i)).toBeVisible();
+  });
 });
diff --git a/src/screens/ManageCategoriesScreen.test.tsx b/src/screens/ManageCategoriesScreen.test.tsx
index ce7193f..631e772 100644
--- a/src/screens/ManageCategoriesScreen.test.tsx
+++ b/src/screens/ManageCategoriesScreen.test.tsx
@@ -22,18 +22,24 @@ vi.mock('../hooks/dataHooks', () => ({
 }));
 
 const categoryDeleteMock = vi.fn();
+const categoryAddMock = vi.fn();
+const categoryUpdateMock = vi.fn();
+const productModifyMock = vi.fn();
 
 vi.mock('../context/DBProvider', () => ({
   useDatabase: () => ({
+    transaction: async (_mode: string, _tableA: unknown, _tableB: unknown, callback: () => Promise<void>) => {
+      await callback();
+    },
     categories: {
-      add: vi.fn(),
-      update: vi.fn(),
+      add: categoryAddMock,
+      update: categoryUpdateMock,
       delete: categoryDeleteMock,
     },
     products: {
       where: () => ({
         equals: () => ({
-          modify: vi.fn(),
+          modify: productModifyMock,
         }),
       }),
     },
@@ -41,6 +47,13 @@ vi.mock('../context/DBProvider', () => ({
 }));
 
 describe('ManageCategoriesScreen deletion safeguards', () => {
+  beforeEach(() => {
+    categoryAddMock.mockReset();
+    categoryUpdateMock.mockReset();
+    categoryDeleteMock.mockReset();
+    productModifyMock.mockReset();
+  });
+
   it('shows an error when trying to delete an in-use category', async () => {
     const user = userEvent.setup();
     render(
@@ -56,4 +69,58 @@ describe('ManageCategoriesScreen deletion safeguards', () => {
       await screen.findByText(/cannot delete 'snacks' while 1 product\(s\) use it/i),
     ).toBeVisible();
   });
+
+  it('adds a category when a unique name is provided', async () => {
+    const user = userEvent.setup();
+    render(
+      <MemoryRouter>
+        <ManageCategoriesScreen />
+      </MemoryRouter>,
+    );
+
+    const nameField = screen.getByLabelText(/category name/i);
+    await user.clear(nameField);
+    await user.type(nameField, 'Drinks');
+    await user.click(screen.getByRole('button', { name: /add/i }));
+
+    expect(categoryAddMock).toHaveBeenCalledTimes(1);
+    expect((nameField as HTMLInputElement).value).toBe('');
+    expect(await screen.findByText(/category added/i)).toBeVisible();
+  });
+
+  it('prevents adding a duplicate category name', async () => {
+    const user = userEvent.setup();
+    render(
+      <MemoryRouter>
+        <ManageCategoriesScreen />
+      </MemoryRouter>,
+    );
+
+    const nameField = screen.getByLabelText(/category name/i);
+    await user.clear(nameField);
+    await user.type(nameField, 'Snacks');
+    await user.click(screen.getByRole('button', { name: /add/i }));
+
+    expect(categoryAddMock).not.toHaveBeenCalled();
+    expect(await screen.findByText(/already exists/i)).toBeVisible();
+  });
+
+  it('updates a category and cascades the change to products', async () => {
+    const user = userEvent.setup();
+    render(
+      <MemoryRouter>
+        <ManageCategoriesScreen />
+      </MemoryRouter>,
+    );
+
+    await user.click(screen.getByRole('button', { name: /edit snacks/i }));
+    const editField = screen.getByDisplayValue(/snacks/i);
+    await user.clear(editField);
+    await user.type(editField, 'Treats');
+    await user.click(screen.getByRole('button', { name: /save category/i }));
+
+    expect(categoryUpdateMock).toHaveBeenCalledWith('cat-1', expect.objectContaining({ name: 'Treats' }));
+    expect(productModifyMock).toHaveBeenCalled();
+    expect(await screen.findByText(/category updated/i)).toBeVisible();
+  });
 });
diff --git a/src/screens/PickListsScreen.test.tsx b/src/screens/PickListsScreen.test.tsx
index c8c90d0..890b6e7 100644
--- a/src/screens/PickListsScreen.test.tsx
+++ b/src/screens/PickListsScreen.test.tsx
@@ -1,5 +1,6 @@
 import { MemoryRouter } from 'react-router-dom';
 import { render, screen, within } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 import { PickListsScreen } from './PickListsScreen';
 
@@ -15,6 +16,10 @@ let pickListsMock = [
   { id: 'list-1', area_id: 'area-1', created_at: 5, categories: [], auto_add_new_products: false },
 ];
 
+const pickListDeleteMock = vi.fn();
+const pickListUpdateMock = vi.fn();
+const pickItemDeleteMock = vi.fn();
+
 vi.mock('../hooks/dataHooks', () => ({
   usePickLists: () => pickListsMock,
   useAreas: () => areasMock,
@@ -24,12 +29,12 @@ vi.mock('../context/DBProvider', () => ({
   useDatabase: () => ({
     pickItems: {
       where: () => ({
-        equals: () => ({ delete: vi.fn() }),
+        equals: () => ({ delete: pickItemDeleteMock }),
       }),
     },
     pickLists: {
-      update: vi.fn(),
-      delete: vi.fn(),
+      update: pickListUpdateMock,
+      delete: pickListDeleteMock,
       where: () => ({
         equals: () => ({ delete: vi.fn() }),
       }),
@@ -39,6 +44,9 @@ vi.mock('../context/DBProvider', () => ({
 
 describe('PickListsScreen sorting', () => {
   beforeEach(() => {
+    pickListDeleteMock.mockReset();
+    pickListUpdateMock.mockReset();
+    pickItemDeleteMock.mockReset();
     areasMock = [
       { id: 'area-1', name: 'Front Counter', created_at: 0, updated_at: 0 },
       { id: 'area-2', name: 'back room', created_at: 0, updated_at: 0 },
@@ -91,4 +99,44 @@ describe('PickListsScreen sorting', () => {
     expect(within(listItems[1]).getByText(/cafe/i)).toBeVisible();
     expect(within(listItems[2]).getByText(/front counter/i)).toBeVisible();
   });
+
+  it('opens the edit dialog and saves changes', async () => {
+    const user = userEvent.setup();
+
+    render(
+      <MemoryRouter>
+        <PickListsScreen />
+      </MemoryRouter>,
+    );
+
+    await user.click(screen.getAllByLabelText(/edit/i)[0]);
+    expect(screen.getByRole('dialog', { name: /edit pick list/i })).toBeVisible();
+
+    await user.selectOptions(screen.getByLabelText(/area/i), 'area-3');
+    await user.clear(screen.getByLabelText(/notes/i));
+    await user.type(screen.getByLabelText(/notes/i), 'Restock quickly');
+    await user.click(screen.getByRole('button', { name: /save changes/i }));
+
+    expect(pickListUpdateMock).toHaveBeenCalledWith('list-2', {
+      area_id: 'area-3',
+      notes: 'Restock quickly',
+    });
+    expect(screen.queryByRole('dialog', { name: /edit pick list/i })).not.toBeInTheDocument();
+  });
+
+  it('deletes a pick list when confirmed', async () => {
+    const user = userEvent.setup();
+    vi.spyOn(window, 'confirm').mockReturnValueOnce(true);
+
+    render(
+      <MemoryRouter>
+        <PickListsScreen />
+      </MemoryRouter>,
+    );
+
+    await user.click(screen.getAllByLabelText(/delete/i)[0]);
+
+    expect(pickItemDeleteMock).toHaveBeenCalled();
+    expect(pickListDeleteMock).toHaveBeenCalledWith('list-2');
+  });
 });