feat(tests): Add comprehensive unit tests for background and popup sc…

[SIkebe]

…ripts

This pull request introduces several enhancements to the project, including automated dependency updates, improved CI/CD workflows, expanded testing capabilities, and new mock utilities for unit testing. The changes aim to streamline development processes, increase test coverage, and improve maintainability.

Dependency Management and CI/CD Enhancements:

• .github/dependabot.yml: Configured Dependabot to automate daily updates for npm dependencies and GitHub Actions workflows, grouping development and production dependencies for better management.
• .github/workflows/ci.yml: Added a CI/CD pipeline to run unit tests, build the project, and provide a summary of test results for pull requests and commits to the main branch.

Testing Improvements:

• package.json: Introduced multiple Jest test scripts (test, test:unit, test:integration, etc.) and added relevant testing dependencies (jest, ts-jest, @types/jest, etc.). [1] [2]
• src/background.ts: Exported key functions for testing purposes, enabling better test coverage for the background script.
• tests/setup/jest.setup.ts: Created a Jest setup file to mock the Chrome API globally, reduce console noise, and add custom matchers for streamlined testing.

Mock Utilities for Unit Testing:

• tests/mocks/chrome-api.mock.ts: Implemented comprehensive Chrome API mocks, including tabs, windows, storage, and display mocks, to facilitate unit testing of Chrome extension features.
• tests/mocks/popup-mock.ts: Added a mock for testing the popup script, simulating DOM interactions, accessibility updates, and Chrome API calls.

[Copilot]

Pull Request Overview

This PR adds a comprehensive suite of unit tests and associated test infrastructure for both the background and popup scripts of the Split Translator extension. Key changes include:

• Test configuration and setup: added tsconfig.test.json, Jest setup, and Chrome API mocks.
• Shared utilities: introduced TestUtils for common test helpers and mock generation.
• New unit tests: created detailed tests for popup behaviors, background script logic, and display/tab handling.
• Adjusted production code: exported internal functions from background.ts to enable testing.

Reviewed Changes

Copilot reviewed 12 out of 16 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tsconfig.test.json	Added test-specific TypeScript configuration with performance optimizations
tests/utils/test-utils.ts	Introduced common test utilities (DOM setup, mock generators, assertion helpers)
tests/unit/popup.test.ts	Added popup script unit tests covering DOM, language selection, button interactions, keyboard navigation, status updates, and error handling
tests/unit/background.test.ts	Added background script unit tests covering constants, error handling, dimension enforcement, tab readiness, display bounds, URL and tab validation
tests/setup/jest.setup.ts	Configured Jest setup with Chrome API mocks, console suppression, custom matchers, and test environment reset
tests/mocks/popup-mock.ts	Introduced PopupMock to simulate DOMContentLoaded and popup behaviors
tests/mocks/chrome-api.mock.ts	Introduced ChromeApiMock for mocking Chrome API interactions in tests
src/background.ts	Exported internal functions for testability
package.json	Added test scripts and devDependencies for Jest and TS-Jest
.npmrc	Removed unnecessary cache configuration
.github/workflows/ci.yml	Configured CI to run unit and integration tests
.github/dependabot.yml	Established Dependabot configuration for dependencies and GitHub Actions workflows

Comments suppressed due to low confidence (2)

tests/unit/popup.test.ts:60

• The test asserts that chrome.storage.sync.get is called but does not verify that the select value is actually updated to the saved language. Consider adding an assertion on targetLanguageSelect.value.

    it('should load saved language preference', async () => {

src/background.ts:277

• The export includes handleSplitAndTranslate which is not defined in this module; it should either export handleSplitView or define the missing function.

    handleSplitAndTranslate,

[Copilot]

This test uses real timers and will wait ~100ms per run, slowing down the suite. Consider using jest.useFakeTimers() and advancing the timer to speed up this timeout test.

Suggested change

	await backgroundModule.waitForTabReady(123, 50);
	const endTime = Date.now();
	const elapsed = endTime - startTime;
	// Should have waited approximately the timeout duration
	expect(elapsed).toBeGreaterThanOrEqual(40); // Allow some margin
	expect(elapsed).toBeLessThan(200); // But not too long
	const promise = backgroundModule.waitForTabReady(123, 50);
	jest.advanceTimersByTime(50);
	await promise;
	// Should have waited approximately the timeout duration