# Handoff Report: Coverage Gap Analysis for `reversecore_mcp/tools/common/assembler.py`

This hard handoff report details the coverage gaps and the testing strategy to achieve 100% test coverage for `assembler.py`.

---

## 1. Observation
We ran the project test suite and generated coverage statistics for `reversecore_mcp/tools/common/assembler.py`:
- **Command executed**: `pytest tests/unit/tools/common/test_assembler.py --cov=reversecore_mcp/tools/common/assembler --cov-report=term-missing`
- **Output obtained**:
  ```
  reversecore_mcp/tools/common/assembler.py                 197     85    57%   69-70, 75-95, 122, 135, 139, 149, 153-163, 166-171, 174-179, 182, 206, 214, 219-222, 225-232, 235-240, 243-248, 251, 322-323, 331, 333, 336-338, 356-362
  ```
- **Verbatim code segments (uncovered)**:
  - **Lines 69-70 & 75-76** (Capstone 6 fallback imports):
    ```python
    try:
        from capstone import CS_ARCH_ARM64
    except ImportError:
        from capstone import CS_ARCH_AARCH64 as CS_ARCH_ARM64
    ```
  - **Lines 139** (ARM v8 mode in `get_keystone_params`):
    ```python
    elif mode_clean == "v8":
        return KS_ARCH_ARM, KS_MODE_ARM + KS_MODE_V8
    ```
  - **Lines 322-323** (`KsError` initialization failure):
    ```python
    except KsError as e:
        raise ToolExecutionError(f"Failed to initialize Keystone engine: {e}")
    ```
  - **Lines 356** (No disassembly instructions found):
    ```python
    else:
        verification_text = "Capstone warning: No instructions disassembled (invalid byte sequence or alignment)."
    ```

---

## 2. Logic Chain
1. **Observation 1**: The coverage report shows a 57% coverage rate for `assembler.py` and specifies 85 missed statements.
2. **Observation 2**: The missed lines match specific parts of `get_keystone_params` and `get_capstone_params` mapped constants, indicating that alternative architectures (e.g. MIPS, PPC, SPARC, SystemZ) and specific modes (e.g., ARM v8 mode, Big Endian modes) are never requested by the existing test suite in `tests/unit/tools/common/test_assembler.py`.
3. **Observation 3**: The missed lines include imports fallback and warning paths (`except ImportError`, `except CsError`, `except KsError`, and `encoding is None`), which require targeted python runtime import interception/mocking and instance/method patching.
4. **Conclusion**: By introducing parameterized tests for all architectural mapping branches, module-reloading mocks to trigger `ImportError` scenarios, and custom class/method mock overrides for Keystone and Capstone exceptions, the test suite can execute every statement and branch, achieving 100% test coverage.

---

## 3. Caveats
- **Assumption**: We assume that the `sys.modules` cleanups during reloading tests will not negatively impact subsequent tests in the same suite. To avoid issues, the module state is fully restored and reloaded at the end of the test.
- **Environment**: The target environment has both `keystone` and `capstone` installed. If either library is not installed, the test suite still runs successfully by matching parameters against the local fallback constants.

---

## 4. Conclusion
To close the coverage gaps for `assembler.py` (from 57% to 100%), the implementation team should replace/augment `tests/unit/tools/common/test_assembler.py` with the complete set of tests drafted in `analysis.md`. This testing strategy targets:
1. All fallback imports and Capstone v6 alternative imports.
2. Parameters for all 21 Keystone architecture/mode combinations and 17 Capstone architecture/mode combinations.
3. Every exception and warning path for Keystone assembly and Capstone verification.

---

## 5. Verification Method
1. Inspect the detailed list of test cases in `/Users/sjkim1127/Reversecore_MCP/.agents/explorer_m7_1_3/analysis.md`.
2. Apply the proposed test cases to `tests/unit/tools/common/test_assembler.py`.
3. Run the following command:
   ```bash
   pytest tests/unit/tools/common/test_assembler.py --cov=reversecore_mcp/tools/common/assembler --cov-report=term-missing
   ```
4. Verify that the coverage for `reversecore_mcp/tools/common/assembler.py` shows **100%** with no missed lines.
