Daily Test Coverage Improver: Add comprehensive API AST map tests

[dsyme]

Summary

This PR adds comprehensive test coverage for Z3's AST map API functions, significantly improving test coverage from 0% to 84% for the src/api/api_ast_map.cpp module.

Problem Found

The AST map API functions (Z3_ast_map_*) had zero test coverage despite being a core part of Z3's AST manipulation capabilities:

• src/api/api_ast_map.cpp: 0% coverage (0/111 lines covered)
• No existing tests exercised the AST map API layer
• Important functionality like map creation, insertion, lookup, deletion, and reference counting was untested

Actions Taken

• Created comprehensive test suite in src/test/api_ast_map.cpp
• Added test registration in src/test/main.cpp and src/test/CMakeLists.txt
• Implemented tests for all major API functions:
  • Basic operations: Z3_mk_ast_map, Z3_ast_map_insert, Z3_ast_map_find, Z3_ast_map_contains, Z3_ast_map_size
  • Map manipulation: Z3_ast_map_erase, Z3_ast_map_reset
  • Reference counting: Z3_ast_map_inc_ref, Z3_ast_map_dec_ref
  • Utility functions: Z3_ast_map_to_string
• Comprehensive test cases covering basic operations, value overwriting, entry deletion, map reset, and edge cases

Changes in Test Coverage Achieved

Before:

• src/api/api_ast_map.cpp: 0% coverage (0/111 lines)
• Overall project coverage: 47% (176,006/373,164 lines)

After:

• src/api/api_ast_map.cpp: 84% coverage (94/111 lines) - +94 lines covered
• Overall project coverage: 47% (176,040/373,341 lines) - +34 net covered lines

Coverage improvement breakdown:

• 94 new lines covered in AST map API functions
• Major functions now tested: All core AST map operations including creation, insertion, lookup, deletion, reset, and reference counting
• Remaining uncovered areas: Error handling paths for invalid operations on lines 73-75, 135, 137-149

Validation Commands

To validate the coverage improvements:

# Build and run the new test
ninja -C build test-z3
./build/test-z3 api_ast_map

# Generate coverage report to verify improvements  
gcovr --merge-mode-functions=separate --gcov-ignore-parse-errors --gcov-executable "llvm-cov gcov" . | grep api_ast_map

Future Improvement Areas

Based on remaining uncovered areas in api_ast_map.cpp:

• Error handling paths - Edge cases with invalid parameters or out-of-memory conditions
• Advanced map operations - Complex scenarios with very large maps or unusual AST combinations

Other high-impact areas for future coverage improvements:

• src/api/api_datalog.cpp (0% coverage, 486 lines) - Datalog API functions
• src/api/api_fpa.cpp (0% coverage, 1090 lines) - Floating-point arithmetic API
• src/api/api_pb.cpp (0% coverage, 64 lines) - Pseudo-boolean API functions

<details>
<summary>Workflow Details</summary>

Bash Commands Run

• git checkout -b daily-test-improver-api-ast-map-tests
• ninja -C build test-z3
• ./build/test-z3 api_ast_map
• gcovr --merge-mode-functions=separate --gcov-ignore-parse-errors --gcov-executable "llvm-cov gcov" . | grep api_ast_map
• git add src/test/api_ast_map.cpp src/test/main.cpp src/test/CMakeLists.txt
• git commit --author "Daily Test Coverage Improver <github-actions[bot]@users.noreply.github.com>" -m "..."

Web Searches Performed

None

Web Pages Fetched

None

</details>

> AI-generated content by Daily Test Coverage Improver may contain mistakes.

Generated by Agentic Workflow Run