test: validate materialized MCP corruption fixtures

[ProfRandom92]

Summary:

• Add deterministic structural validation tests for the materialized MCP corruption fixtures and assert the exact structural violations for DROP_APPROVAL_GATE, REMOVE_DEPENDENCY_EDGE, and TRUNCATE_RECOVERY_PATH.

Changed files:

• tests/test_mcp_trace_corruption_validation.py (new)

Testing:

• Ran pytest -q tests/test_mcp_trace_corruption_validation.py and observed 4 passed.
• Ran the full test sweep via npm run check which executed pytest and the project checks and completed successfully (304 passed overall as part of the run).

Risks:

• Low risk: this is a test-only change that does not modify fixtures, manifests, validators, taxonomy labels, workflows, package files, or evidence indexes.

Next:

• Future work can materialize additional operators or wire these validated corrupted fixtures into higher-level replay-integrity benchmark checks.

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Codex Task

[gemini-code-assist]

Code Review

This pull request introduces a new test suite, tests/test_mcp_trace_corruption_validation.py, which validates the integrity and structural correctness of MCP trace corruption fixtures. The tests ensure that corruption operators like DROP_APPROVAL_GATE, REMOVE_DEPENDENCY_EDGE, and TRUNCATE_RECOVERY_PATH are correctly applied to source fixtures while maintaining the consistency of non-target files. Review feedback focuses on improving the robustness of JSON loading and data processing by replacing assertions with explicit error handling and adding type guards to prevent potential crashes on malformed input data.