COMPLETED

Status: All edge case tests implemented and passing
Test Function: TestImportInjectionEdgeCases
Test Cases: 6/6 passing
File: pkg/preprocessor/import_edge_cases_test.go
Lines of Code: 252
Test Execution Time: 0.406s

Edge Cases Covered:
1. Multiple imports from same package (deduplication) ✓
2. Imports from different packages ✓
3. No imports needed (no stdlib calls) ✓
4. Already existing imports (don't duplicate) ✓
5. Source map offsets correct for different import counts ✓
6. Mixed qualified and unqualified calls ✓

Verification:
- ImportTracker correctly deduplicates ✓
- Source map offsets correct for different numbers of imports ✓
- All tests passing with zero failures ✓

Command to run tests:
go test ./pkg/preprocessor -run TestImportInjectionEdgeCases -v

Result: SUCCESS
