fix: Fix test extension loading paths and Makefile (issue #8)

[dirtyfilthy]

Description

This PR fixes three critical bugs that prevented tests from running:

1. Extension Loading Path Issue: SQLite's sqlite3_load_extension() automatically appends .so (or .dylib on macOS) to extension paths. Tests were passing paths like "../build/libgraph.so", causing SQLite to attempt loading "../build/libgraph.so.so", which failed.

2. Makefile References Non-Existent Tests: The Makefile referenced test files that don't exist (test_loading, test_insert_nodes, test_query_nodes), causing make test to fail immediately.

3. Dynamic Symbol Resolution Issue: Tests statically linked SQLite but dynamically loaded the extension. The extension couldn't resolve SQLite symbols because they weren't exported from the test binary.

Related Issues

Closes #8

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📝 Documentation update
• 🔧 Build/CI configuration change
• ♻️ Code refactoring (no functional changes)
• ⚡ Performance improvement
• ✅ Test improvement

Changes Made

• Fixed extension loading paths in 58 test files (removed .so/.dylib suffixes)
• Updated tests/Makefile to reference only existing test files
• Added -Wl,--export-dynamic to LDFLAGS for dynamic symbol resolution
• Fixed TCK test generator (generate_tck_tests.py) to produce correct paths

Testing

• All existing tests pass (make test)
• Added new tests for new functionality
• Tested with Valgrind for memory leaks
• Tested with AddressSanitizer
• Manual testing performed
• Performance testing performed (if applicable)

Test Evidence

Before fixes:

$ cd tests && make test
make: *** No rule to make target 'test_loading.c', needed by 'test_loading'.  Stop.

After fixes:

$ cd tests && make test
=== Running Basic Tests ===
Running test_match_return_simple...
✅ test_match_return_simple PASSED

Running test_storage...
✅ test_storage PASSED

Running test_virtual_table_crud...
✅ test_virtual_table_crud PASSED

Running test_performance...
✅ test_performance PASSED

🎉 ALL BASIC TESTS PASSED!

Documentation

• Updated API documentation
• Updated README.md (if needed)
• Updated CHANGELOG.md
• Added code comments where necessary
• Updated examples (if applicable)

Checklist

• My code follows the project's code style guidelines
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have checked for memory leaks
• I have updated the documentation accordingly
• My changes are compatible with the supported platforms (Linux x86_64)

Breaking Changes

N/A

Performance Impact

• No performance impact
• Performance improved
• Performance slightly degraded (justified because...)
• Performance significantly degraded (needs discussion)

Screenshots / Examples

N/A

Additional Context

This fix addresses the root cause of test failures. The changes are minimal and focused:

• Only path strings were modified (no test logic changes)
• Makefile updated to reflect actual test files
• Single linker flag added for proper symbol resolution

All 4 basic tests now pass successfully.

Reviewer Notes

Please verify:

1. Extension paths are correct (no .so/.dylib suffixes)
2. Makefile only references existing test files
3. Tests run successfully with make test

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For Maintainers:

• Code review completed
• All CI checks passing
• Documentation reviewed
• Version number updated (if needed)
• CHANGELOG.md updated