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Can you give me some ideas for purely-inside-the-frontend unit tests that would make sense to add to a Next.js frontend that pulls its data from a Sitecore XM Cloud Layout Service API? Feel free to use mocking to break things up (e.g. testing that a dropdown’s options don’t overflow the screen width separately from testing that the options count matches the record count found within the data that populates it). Please be very thorough; I love well-tested code. The frontend results in public-facing brochureware-style web sites

Here are thorough, frontend-only unit test ideas for a Next.js brochureware site using Sitecore XM Cloud Layout Service API, focusing on pure UI/component logic with mock data:

Component Rendering \& Structure

• Components render expected elements for given mock Sitecore API data (e.g., hero banners, content blocks, navigation).
• Fallback UI appears when data is missing or incomplete (e.g., loading spinners, error messages).
• Correct Sitecore field values (text, images, links) are displayed in the right locations.

Data-Driven UI Logic

• Dropdowns: The number of options matches the length of the mock data array.
• Dropdown options render correct labels and values from mock data.
• Edge case: Dropdown options gracefully handle empty or null data arrays.
• Lists/grids: Correct number of items rendered from mock data, with accurate keys.

Visual \& Accessibility Checks

• Dropdown menu never overflows screen width, even with long option labels (test with artificially long mock data).
• All interactive elements (buttons, links, dropdowns) have accessible labels and roles.
• Images have alt text from Sitecore data or fallback text.

User Interaction

• Clicking a navigation link updates the active state and triggers the correct callback.
• Dropdown selection updates component state and calls the handler with the right value.
• Expanding/collapsing accordions or tabs works as expected, with correct ARIA attributes.

Edge Cases \& Error Handling

• Components handle missing or malformed Sitecore fields without crashing.
• Graceful fallback when image URLs are broken or missing.
• Renders a “no results” message if mock API returns an empty array.

Utility Functions

• Functions that transform Sitecore API data (e.g., formatting dates, parsing rich text) return expected results for various input shapes.

Mocking \& Isolation

• Mock the Sitecore Layout Service API using tools like MSW or Jest mocks to provide consistent, predictable data for each test¹²³.
• Test each component in isolation from its data source, verifying only its rendering and behavior given specific props.

For best practices, group related tests, keep them focused, and use descriptive test names⁴⁵.

These tests ensure your frontend behaves correctly regardless of the Sitecore backend, catching UI and logic bugs early.

That was awesome, thanks. Given what a typical Sitecore Layout Service API response tends to look like, and given the Sitecore Next.js SDK’s types and classes and functions and whatnot, what are some example folder/file path names (plus corresponding .spec test file names) you’d break the frontend code up into for such a web site, and why?

Here’s a practical folder/file structure for a Next.js + Sitecore XM Cloud project, with matching test file names and rationale:

Example Structure

src/
  components/
    shared/
      Button/
        Button.tsx
        Button.spec.tsx
      Dropdown/
        Dropdown.tsx
        Dropdown.spec.tsx
    layout/
      Header/
        Header.tsx
        Header.spec.tsx
      Footer/
        Footer.tsx
        Footer.spec.tsx
    feature/
      HeroBanner/
        HeroBanner.tsx
        HeroBanner.spec.tsx
      ContentBlock/
        ContentBlock.tsx
        ContentBlock.spec.tsx
  utils/
    formatDate.ts
    formatDate.spec.ts
  hooks/
    useSitecoreData.ts
    useSitecoreData.spec.ts
  types/
    sitecore.ts
  pages/
    index.tsx
    about.tsx
  styles/
  assets/

Rationale

• components/shared/: Reusable UI elements (e.g., Button, Dropdown) with colocated tests for isolation and clarity⁶⁷.
• components/layout/: Site-wide layout pieces (Header, Footer) with their own tests, ensuring consistent rendering⁸⁷.
• components/feature/: Components tied to Sitecore data structures (e.g., HeroBanner, ContentBlock), each with a .spec.tsx for data-driven rendering and logic⁶⁷.
• utils/: Utility functions (e.g., formatting, data mapping) with direct unit tests⁶.
• hooks/: Custom React hooks (like data fetching or transformation) with tests for logic and error handling⁶.
• types/: TypeScript definitions for Sitecore Layout Service responses, keeping types centralized and maintainable⁶.
• Colocated tests: Each component or utility has a matching .spec.tsx or .spec.ts for focused, maintainable testing⁷.
• Feature-based grouping: Keeps related files together, making it easy to scale and maintain as the site grows⁹⁷.

This structure is clean, scalable, and directly supports robust unit testing for a Sitecore-powered Next.js frontend.

No specs for the pages?

Great catch! Testing pages in a Next.js + Sitecore setup is valuable, especially for logic, integration, and rendering checks. Here’s how and why you’d do it, and how to organize the files:

Should You Test Pages?

• Yes, but… Pages in Next.js often orchestrate data fetching (e.g., getStaticProps, getServerSideProps) and compose components.
  • Unit tests: Focus on logic, rendering with mock data, and error handling.
  • Integration tests: Check component composition and data flow.
  • End-to-end tests: (e.g., Cypress, Playwright) are best for full navigation and API integration, but not “unit” tests.

Example Folder/File Structure (with Page Specs)

src/
  pages/
    index.tsx
    index.spec.tsx
    about.tsx
    about.spec.tsx

What Would You Test in Page Specs?

• Rendering: Page renders expected components for given mock Sitecore data.
• Data fetching: getStaticProps or getServerSideProps returns correct props for mock API responses.
• Error states: Page handles missing/bad data gracefully (e.g., error messages, fallback UIs).
• SEO tags: Correct <title>, meta tags, and Open Graph data are rendered from Sitecore fields.
• Component composition: Correct components are rendered in the right order with correct props.

Example: index.spec.tsx

import { render, screen } from '@testing-library/react';
import IndexPage, { getStaticProps } from './index';

jest.mock('../components/feature/HeroBanner', () => () => <div>MockBanner</div>);

describe('Index Page', () => {
  it('renders the hero banner with mock data', async () => {
    const mockProps = { /* mock Sitecore data shape */ };
    render(<IndexPage {...mockProps} />);
    expect(screen.getByText('MockBanner')).toBeInTheDocument();
  });

  it('getStaticProps returns expected props', async () => {
    // Mock fetch to Sitecore Layout Service
    const result = await getStaticProps();
    expect(result).toHaveProperty('props');
    // Further assertions on props shape/values
  });

  it('shows error message if data is missing', () => {
    render(<IndexPage /* missing/empty data */ />);
    expect(screen.getByText(/error/i)).toBeInTheDocument();
  });
});

Why Test Pages?

• Catches integration bugs between data fetching and component rendering.
• Ensures error handling for real-world Sitecore data issues.
• Validates page-level logic (e.g., conditional rendering, SEO).

Summary: Colocate .spec.tsx files with your pages to ensure robust, maintainable, and comprehensive test coverage-especially for data-driven, public-facing brochureware sites!

Any enhancements to all of the advice you’ve given me so far, considering that a major reason to use Sitecore’s Next.js SDK is to make brochureware whose components can be dragged and dropped around the screen in Experience Editor?

Absolutely-when supporting drag-and-drop component editing in Sitecore Experience Editor, you should enhance your architecture and testing approach in these ways:

Folder/File Structure Enhancements

• Component modularity: Ensure every drag-and-droppable component is a standalone React component in components/feature/ or components/shared/, with its own props, rendering logic, and .spec.tsx test file.
• Rendering logic: Use a central components/Rendering/ or similar folder for the Sitecore Next.js SDK’s <Rendering /> or <ComponentFactory /> logic, which dynamically renders components based on Sitecore’s layout data. Add Rendering.spec.tsx to test that the correct component is rendered for each Sitecore rendering definition.
• Editable fields: Place field wrappers (e.g., Text, Image, RichText from @sitecore-jss/sitecore-jss-react) in a fields/ subfolder. Test these with .spec.tsx files to ensure they render editable markup in Experience Editor mode.

Testing Enhancements

• Experience Editor mode: Add tests that simulate Experience Editor context (e.g., by mocking the editing prop or context) to verify that:
  • Components render Sitecore “chrome” (borders, handles) when in editing mode.
  • Editable fields are rendered as <span> or <div> with the correct Sitecore attributes.
  • Drag-and-drop handles appear and function as expected in the DOM.
• Component registration: Test your component factory (the mapping between Sitecore component names and React components) to ensure all components are registered and renderable by Experience Editor.
• Layout data handling: Test that the page and layout containers correctly render child components based on mock Sitecore layout data, including nested and reordered components.
• Editor-specific utilities: If you use utilities like handleEditorFastRefresh (to preserve Experience Editor markup during Fast Refresh), add a utils/editor.ts file and corresponding editor.spec.ts to test these behaviors¹⁰.

Example Structure

src/
  components/
    feature/
      HeroBanner/
        HeroBanner.tsx
        HeroBanner.spec.tsx
      PromoBlock/
        PromoBlock.tsx
        PromoBlock.spec.tsx
    Rendering/
      ComponentFactory.tsx
      ComponentFactory.spec.tsx
  fields/
    TextField.tsx
    TextField.spec.tsx
    ImageField.tsx
    ImageField.spec.tsx
  utils/
    editor.ts
    editor.spec.ts

Why

• Experience Editor compatibility is a core value of Sitecore’s Next.js SDK. Testing for edit mode ensures editors can drag, drop, and edit components without regression.
• Component isolation and factory testing guarantee that new or reordered components work seamlessly in both browse and edit modes.
• Field-level testing ensures that content editors see the correct editable UI for each field, reducing editor friction and bugs.

By structuring your code and tests this way, you maximize maintainability and reliability for both developers and content editors using Experience Editor¹⁰¹¹¹².

What nuances of brochureware frontend unit test case planning might I want to differentiate when thinking about code that renders lower-order (often more real-world-ey) vs. higher-order (often more presentation-ey) objects delivered by the Sitecore Layout Service API?

When planning unit tests for a Sitecore-powered brochureware frontend, it’s important to differentiate between lower-order (data-rich, real-world, business-object) and higher-order (layout, presentation, container) objects from the Layout Service API. Here are key nuances to consider:

Lower-Order Objects (Real-World, Data-Driven)

• Test data mapping and transformation: Ensure fields from Sitecore (e.g., titles, images, links) are correctly mapped and rendered in components, using mock data that closely resembles real-world API responses¹³¹⁴.
• Business logic isolation: Encapsulate and test any business logic (e.g., filtering, formatting, conditional rendering) outside of views for maximum reusability and testability¹⁴.
• Edge case coverage: Write tests for missing, malformed, or unexpected field values, since these objects reflect real editorial data with possible inconsistencies.
• Mocking Sitecore context: Use mocks or abstractions to simulate Sitecore context/data, so tests remain pure unit tests and not integration tests¹⁵¹⁴.

Higher-Order Objects (Presentation, Layout)

• Composition and rendering: Focus tests on whether the correct child components are rendered in the right order and with the right props, given a particular layout data structure¹⁴.
• Personalization and variants: If the layout includes personalized or variant renderings, test that the correct components render under different simulated personalization conditions¹⁶.
• Experience Editor support: For drag-and-drop editing, ensure tests verify that layout containers and presentation components render the necessary Sitecore “chrome” and editable wrappers when in editing mode.
• Minimal business logic: Higher-order components should have little to no business logic; tests should focus on structure, not data transformation¹⁴.

Test Planning Nuances

Summary: Unit tests for lower-order objects should deeply validate data handling and logic, while tests for higher-order objects should focus on correct composition, layout, and Experience Editor compatibility-keeping business logic out of layout/presentation code for maintainability and robust testing¹⁶¹³¹⁴.