# Handoff Report — Test Coverage Improvements for `assembler.py`

## 1. Observation

- **Modified Test File**: `/Users/sjkim1127/Reversecore_MCP/tests/unit/tools/common/test_assembler.py`
- **Target File**: `/Users/sjkim1127/Reversecore_MCP/reversecore_mcp/tools/common/assembler.py`
- **Initial Verification**: Run `pytest tests/unit/tools/common/test_assembler.py -v` after initial implementation failed with:
  ```
  FAILED tests/unit/tools/common/test_assembler.py::test_capstone_v6_attribute_fallbacks - AssertionError: assert <MagicMock name='mock.CS_ARCH_ARM64' id='4458333104'> == 9999
  FAILED tests/unit/tools/common/test_get_capstone_params_all_architectures[arm64-64-CS_ARCH_ARM64-CS_MODE_ARM] - AssertionError: assert 1 == <MagicMock name='mock.CS_ARCH_ARM64' id='4458333104'>
  ```
- **Keystone Engine Availability**: Executing `python -c "import keystone"` failed on the host system:
  ```
  ImportError: ERROR: fail to load the dynamic library.
  ```
  Consequently, in `assembler.py`, `KsError` is assigned to `Exception`.
- **Initial Coverage**: Initial run had `reversecore_mcp/tools/common/assembler.py                 197      2    99%   336-338`. Lines 336-338 (generic exception catch block `except Exception as e:`) were marked as uncovered.
- **Final Test Verification**: Running `pytest tests/unit/tools/common/test_assembler.py -v` completed successfully with:
  ```
  reversecore_mcp/tools/common/assembler.py                 197      0   100%
  ...
  58 passed in 2.99s
  ```

## 2. Logic Chain

1. **Namespace Mismatches in Reload Tests**:
   - *Observation*: The initial import-reload mocks of Capstone/Keystone modules resulted in `sys.modules` being populated by a reloaded mock module object, which had attributes like `CS_ARCH_ARM64 = 9999`.
   - *Observation*: Meanwhile, the top-level test namespace and functions like `get_capstone_params` were imported before reloading and bound to the original module namespace (where `CS_ARCH_ARM64 = 1`).
   - *Reasoning*: Because the parameterized tests compared values using `actual_arch` (from original module) against `getattr(assembler_mod, cs_arch_attr)` (from the reloaded module in `sys.modules`), they threw attribute mismatches.
   - *Fix*: Rewriting parameterized tests to call functions directly from the dynamically imported module `assembler_mod.get_capstone_params` and `assembler_mod.get_keystone_params` kept functions and constants in the same module namespace, preventing mismatch failures.

2. **Attribute Mismatch in Mocking**:
   - *Observation*: Mocking with `MagicMock` caused standard `dir()` checks to succeed but did not throw `AttributeError` for undefined attributes.
   - *Reasoning*: Because Python imports trigger fallback logic on `AttributeError` and `MagicMock` intercepts missing attributes instead of raising `AttributeError`, the fallback logic was bypassed.
   - *Fix*: Built a custom module-like class `MockCapstoneModule` lacking `CS_ARCH_ARM64` and `CS_ARCH_SYSZ` so it throws the appropriate `AttributeError` and correctly triggers the fallback import paths.

3. **Keystone Exception Coverage**:
   - *Observation*: Since Keystone dynamic library failed to load, `KsError` in `assembler.py` defaulted to `Exception`.
   - *Reasoning*: As a result, the generic `except Exception as e:` handler at lines 336-338 was bypassed by the earlier `except KsError as e:` block.
   - *Fix*: Patched `KsError` to a distinct exception type `MockKsError` in the generic exception test so that raising `ValueError` in `MockKsGenericError.asm()` correctly fell through to the `except Exception` branch.

## 3. Caveats

- **Host Keystone Installation**: Keystone library could not be fully loaded on the host environment due to dynamic library loading issues. If Keystone dynamic library is fully available in other environments, the tests will still pass because we patched `KsError` correctly in isolation.

## 4. Conclusion

All 58 test cases in `tests/unit/tools/common/test_assembler.py` pass cleanly. We successfully achieved 100% test coverage on `reversecore_mcp/tools/common/assembler.py` and formatted/validated the codebase.

## 5. Verification Method

- Run the following command in the workspace directory:
  ```bash
  pytest tests/unit/tools/common/test_assembler.py -v
  ```
- Inspect the coverage table output at the end of the pytest run to confirm `reversecore_mcp/tools/common/assembler.py` has reached `100%` coverage with `0` missed lines.
