# Task 2 Report: Valueless Six-Decimal Mock Asset

## Implementation

Added `MockUSDC`, an educational ERC-20 mock with no monetary value. It uses OpenZeppelin `ERC20` and `Ownable`, initializes the token as `Mock USD Coin` (`mUSDC`), overrides `decimals()` to return `6`, and permits `mint(address,uint256)` only to the configured owner. OpenZeppelin rejects `address(0)` as the initial owner via `OwnableInvalidOwner`.

## Changed Files

- `src/MockUSDC.sol` (new): minimal six-decimal owner-mintable ERC-20 mock.
- `test/MockUSDC.t.sol` (new): focused tests for metadata, zero supply, authorized/unauthorized minting, transfer, approval, and zero-owner rejection.

## TDD Evidence

Before writing production code, the test suite was added. The production change that each test guards was identified as a missing or incorrect ERC-20 observable behavior: metadata/decimals, initial supply, owner authorization and mint balances, transfer balance movement, approval allowance, or constructor owner validation.

### RED

Command:

```bash
PATH=/home/golem/.foundry/bin:$PATH forge test --match-path test/MockUSDC.t.sol -vvv --force
```

Relevant output:

```text
Error (6275): Source "src/MockUSDC.sol" not found: File not found.
 --> test/MockUSDC.t.sol:6:1:
Error: Compilation failed
```

This was the expected RED result: the test imports the intentionally absent `src/MockUSDC.sol`; it failed because the requested feature did not yet exist, not because of a test typo or unrelated failure.

### GREEN

Commands:

```bash
PATH=/home/golem/.foundry/bin:$PATH forge fmt
PATH=/home/golem/.foundry/bin:$PATH forge test --match-path test/MockUSDC.t.sol -vvv --force
```

Relevant output:

```text
Ran 7 tests for test/MockUSDC.t.sol:MockUSDCTest
Suite result: ok. 7 passed; 0 failed; 0 skipped
```

## Full Relevant Suite

Command:

```bash
PATH=/home/golem/.foundry/bin:$PATH forge test -vvv
```

Result:

```text
Ran 1 test suite: 7 tests passed, 0 failed, 0 skipped (7 total tests)
```

`git diff --check` also completed without reporting whitespace errors.

## Self-Review

- Implementation contains only the briefed `ERC20`, `Ownable`, `decimals`, and owner-only `mint` behavior; no faucet, burn, permit, blacklist, proxy, or bank-specific logic was added.
- Tests exercise the deployed contract's observable state and OpenZeppelin's real authorization behavior; no mocks were used.
- The non-owner case uses the required exact `Ownable.OwnableUnauthorizedAccount` selector and `stranger` address.
- Mutations such as changing metadata/decimals, allowing arbitrary minting, omitting minting, misrouting transfers, failing to set allowance, or accepting a zero owner are covered by at least one test.

## Concerns

None. The report itself is intentionally left uncommitted because the task required committing only `src/MockUSDC.sol` and `test/MockUSDC.t.sol`.

## Fix Round 1: Literal Command Evidence

Foundry was placed on `PATH` before each command session with a separate shell environment setup step. The commands below were then executed literally, with no inline `PATH` prefix.

### Isolated RED Reproduction

An isolated temporary filesystem copy of the complete worktree (including the already-installed pinned dependencies) was created under `/tmp`, and only `src/MockUSDC.sol` was removed from that copy. This keeps the real committed worktree untouched while preserving the same test file and dependency graph.

Covering test file: `test/MockUSDC.t.sol`

Literal command:

```bash
forge test --match-path test/MockUSDC.t.sol -vvv --force
```

Relevant output:

```text
Error (6275): Source "src/MockUSDC.sol" not found: File not found.
 --> test/MockUSDC.t.sol:6:1:
Error: Compilation failed
```

This RED result is correct because the isolated state retains the new test but deliberately lacks the production contract it imports. The failure is therefore the expected feature-missing failure, rather than a dependency, compiler, or test error.

### Real-Worktree GREEN

Literal commands:

```bash
forge fmt
forge test --match-path test/MockUSDC.t.sol -vvv --force
```

Relevant output:

```text
Ran 7 tests for test/MockUSDC.t.sol:MockUSDCTest
Suite result: ok. 7 passed; 0 failed; 0 skipped
```

### Full Relevant Suite

Literal command:

```bash
forge test -vvv
```

Result:

```text
Ran 1 test suite: 7 tests passed, 0 failed, 0 skipped (7 total tests)
```

No tracked implementation or test file changed during this correction, so no tracked commit was needed. Commit `1f4175b feat: add valueless mock USDC` remains the sole task commit.