Update test documentation with segfault and concurrency test details

Author: claude

docs/TEST_COVERAGE_SUMMARY.md

@@ -13,12 +13,12 @@ This document summarizes the expanded test coverage for python_prtree. The test
 - **Organization**: All tests in a single file
 
 ### After (New Test Structure)
-- **21 test files** organized by category
-- **Unit tests**: 11 files covering individual features
+- **26 test files** organized by category
+- **Unit tests**: 16 files covering individual features
 - **Integration tests**: 5 files covering feature interactions
 - **End-to-end tests**: 3 files covering user workflows
 - **Legacy tests**: Original file preserved for reference
-- **~2000+ lines** of comprehensive test code
+- **~4000+ lines** of comprehensive test code
 
 ## Test Coverage by Feature
 

tests/README.md

@@ -103,6 +103,11 @@ Test individual functions and methods in isolation:
 - **test_object_handling.py**: Object storage and retrieval
 - **test_properties.py**: Properties (size, len, n)
 - **test_precision.py**: Float32/64 precision handling
+- **test_segfault_safety.py**: Segmentation fault safety tests
+- **test_crash_isolation.py**: Crash isolation tests (subprocess)
+- **test_memory_safety.py**: Memory safety and bounds checking
+- **test_concurrency.py**: Python threading/multiprocessing/async tests
+- **test_parallel_configuration.py**: Parallel execution configuration tests
 
 ### Integration Tests (`tests/integration/`)
 Test interactions between multiple components: