[PR #38] p2: executeOperation callback body (steps a-l) has zero deterministic test coverage

[obchain]

Summary

CharonLiquidator.t.sol Section A tests the two entry gates of executeOperation (!pool, !initiator). No test exercises any code beyond those two require statements. The 12 steps documented in the executeOperation NatSpec — Venus liquidation, collateral redemption, PancakeSwap swap, profit sweep, balance verification, and Aave repayment approval — are covered only by the skipped fork test.

This means the following code paths have zero test coverage:

• Step a: abi.decode(data, (LiquidationParams))
• Step b: require(asset == p.debtToken, "asset/debt mismatch") and require(amount == p.repayAmount, "amount/repay mismatch")
• Step c: IERC20.approve + IVToken.liquidateBorrow + liqErr check
• Step d: approval zero-out
• Step e: IVToken.balanceOf + redeem + vBal > 0 check + redeemErr check
• Step f: IERC20(collateral).balanceOf + ISwapRouter.exactInputSingle + minSwapOut enforcement
• Step g: router approval zero-out
• Step h: require(finalBal >= totalOwed, "swap output below repayment")
• Step i: profit transfer to owner
• Step j: LiquidationExecuted event emission
• Step k: Aave approval for totalOwed
• Step l: return true

Location

contracts/test/CharonLiquidator.t.sol — Sections A, B, C, D all bypass executeOperation's liquidation body. Section E is skipped.

PRD / invariant violated

This is the core fund-moving logic of the entire protocol. The CLAUDE.md safety invariants — profit swept to cold wallet, Aave repaid correctly — apply to code that is completely untested by this PR.

Risk

The three p0/p1 bugs already filed (#120 profit-to-hot-wallet, #121 vBNB path broken, #122 fee tier hardcoded) all live inside the untested body. A test suite that passes green while these bugs exist provides false assurance. A mocked walkthrough of executeOperation — using stub vToken and stub router contracts that return controlled values — would have surfaced all three bugs without requiring a fork.

Fix

Add at least one deterministic unit test that exercises the happy path of executeOperation end-to-end using stub/mock external contracts (stub Aave pool that calls executeOperation directly, stub vToken that returns 0 for liqErr and redeemErr, stub router that transfers a fixed debtToken amount). Assert:

• LiquidationExecuted emitted with correct args
• profit amount transferred to expected address
• Aave pool approved for totalOwed

Refs #38

[obchain]

Fixed via commit 6447016. Added test_executeOperation_fullCallback_emitsAndSweepsProfit which drives CharonLiquidator.executeOperation end-to-end with pranked AAVE_POOL as msg.sender, in-file MockVToken (wired dvt.seizeTarget -> cvt to mirror Venus' cross-vToken credit), MockSwapRouter that pulls tokenIn via transferFrom and mints tokenOut, and MockERC20 with full allowance semantics. Asserts: callback returns true, profit = swapOut - (repay + premium) is swept to owner, liquidator holds exactly totalOwed post-callback, the Aave Pool allowance equals totalOwed, and both router and vToken approvals are zeroed after consumption.