Unit testing

[DenHelloWorld]

Pull Request: Unit Testing

1. Task URL

React: Unit Testing

2. Screenshot

3. Deployment

N/A

4. Done 11.05.2026 / Deadline 12.05.2026

5. Score: 100 / 100

Self-Check:

Feature 1: Test Coverage (+14 points)

• Statement coverage is 100% (min 80% required).
• Branch, function, and line coverage are 100% (min 50% required).

Feature 2: No Functional Changes (+14 points)

• All components remain Class Components.
• Logic of the components was not modified.

Feature 3: Behavior-Focused Testing (+14 points)

• Tests focus on user-visible behavior (rendering, clicking, typing) using React Testing Library.
• No internal implementation details (state, private methods) are tested.

Feature 4: API Mocking (+14 points)

• All external API calls are mocked using MSW (Mock Service Worker).
• No real network requests are made during testing.

Feature 5: Error Handling (+14 points)

• API error scenarios (500 status) are covered by tests.
• Error Boundary is tested to ensure it catches errors and displays fallback UI.

Feature 6: User Interactions (+14 points)

• Clicks, input changes, and form interactions are fully covered.
• Edge cases like empty inputs or whitespace are handled.

Feature 7: LocalStorage Functionality Testing (+16 points)

• Tests verify reading the search term from localStorage on mount.
• Tests verify writing the trimmed search term to localStorage after search.