Add comprehensive unit tests for Login component

[devin-ai-integration]

Add comprehensive unit tests for Login component

Summary

This PR introduces a complete testing infrastructure for the component library and adds comprehensive unit tests for the Login component. Since no testing framework was previously configured, this includes setting up Jest, React Testing Library, and Babel from scratch.

Key Changes:

• Testing Infrastructure: Set up Jest + React Testing Library + Babel configuration
• 35 Unit Tests: Comprehensive test coverage for the Login component including:
  • Component rendering with different props (logo, brandName, themeColor)
  • Form validation and submission behavior
  • User interactions (input changes, checkbox, button clicks)
  • Social login functionality with multiple providers
  • Loading states and error message display
  • Conditional rendering scenarios
  • Accessibility features and ARIA attributes
  • Edge cases and error handling

All tests pass and I've verified that the tests can detect real issues by temporarily breaking the component logic.

Review & Testing Checklist for Human

• Test Quality Review: Examine the 35 test cases in Login.test.js - are they testing meaningful user behaviors vs implementation details? Any tests that seem brittle or redundant?
• Build System Compatibility: Verify that the new Babel configuration doesn't conflict with the existing tsup build system by running npm run build and checking output
• Test Coverage Gaps: Review the Login component functionality against the test cases - are there any important user flows or edge cases missing from the tests?
• Dependency Necessity: Check if all the new testing dependencies in package.json are actually needed, and verify no version conflicts with existing dependencies

Recommended Test Plan:

1. Run npm test to ensure all tests pass in your environment
2. Run npm run build to verify build system still works correctly
3. Try temporarily breaking the Login component logic and re-run tests to verify they catch issues
4. Review test descriptions and ensure they align with expected Login component behavior

---

Diagram

%%{ init : { "theme" : "default" }}%%
graph TD
    PackageJson["package.json<br/>(test scripts + Jest config)"]:::major-edit
    BabelConfig["babel.config.js<br/>(new Babel presets)"]:::major-edit
    SetupTests["src/setupTests.js<br/>(Jest setup)"]:::major-edit
    LoginTest["src/components/Login/Login.test.js<br/>(35 comprehensive tests)"]:::major-edit
    LoginComponent["src/components/Login/Login.js<br/>(Login component)"]:::context
    TsupConfig["tsup.config.js<br/>(existing build config)"]:::context
    
    PackageJson -->|"configures"| LoginTest
    BabelConfig -->|"transforms JSX"| LoginTest
    SetupTests -->|"test setup"| LoginTest
    LoginTest -->|"tests"| LoginComponent
    TsupConfig -->|"builds"| LoginComponent
    
    subgraph Legend
        L1["Major Edit"]:::major-edit
        L2["Minor Edit"]:::minor-edit
        L3["Context/No Edit"]:::context
    end

classDef major-edit fill:#90EE90
classDef minor-edit fill:#87CEEB
classDef context fill:#FFFFFF

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Notes

• This is the first testing setup for the component library, establishing patterns for future component tests
• The Jest configuration is inline in package.json - consider moving to separate jest.config.js if it grows
• Tests use React Testing Library's user-centric approach, focusing on behavior over implementation
• All existing functionality remains unchanged - this is purely additive testing infrastructure

Session Details:

• Requested by: ben.lehrburger@windsurf.com (@ben-windsurf)
• Link to Devin run: https://app.devin.ai/sessions/e14d3108cebc4662b5b9b6946418eb8a

[devin-ai-integration]

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