Create/Do tests

[thomhet]

The project require:

Setup and Getting Started with Testing: Using Vitest
Demonstration of snapshot testing

• Testing custom components (testing props, state, and user interactions)
• Using mocking to prevent tests from fetching live data
• Cross-browser and mobile device testing of the application (limited to the devices available to the group)

[ayushb]

Automated side is done: 84 tests across 12 files, run with npm run test. Covers components on props, state and user interaction, 4 snapshot tests, and both storage apis through App.test.tsx. All network calls are mocked so the suite never contacts pokeapi.

Manual side done on the devices we have:

• Chrome 153 on macOS 26.2
• Safari 26.2 on macOS 26.2
• iPhone, Safari

Checked browsing back and forth, jumping to an id, picking from the list, filters surviving a reload, and favourites surviving a browser restart. Functionality behaved as expected on all of them.

The mobile layout still needs work, that is tracked separately in #11.