- Fix login-form.test.tsx: replace undefined 'form' variable with proper element check
- Fix event-list.test.tsx: use getAllByRole('combobox') for select elements without labels
- Fix event-list.test.tsx: match actual error message text instead of generic message
- Fix dashboard.test.tsx: match actual error message and support different number formatting
- Create login-form.test.tsx with 8 test cases (positive and negative)
- Create register-form.test.tsx with 10 test cases
- Set up test directory structure at frontend/src/components/__tests__
- Mock auth-context and next/navigation for testing