# ApproveInventoryAdjustment

## Overview

approveInventoryAdjustment approves a pending inventory adjustment, transitioning it from PENDING_APPROVAL to APPROVED status. An approved adjustment can then be confirmed to apply the stock level changes.

## Business Rules

- Adjustment must exist
- Adjustment must be in PENDING_APPROVAL status

## Process Flow

```mermaid
flowchart TD
    A[Receive approve request] --> B{Adjustment exists?}
    B -->|No| C[Return error: ADJUSTMENT_NOT_FOUND]
    B -->|Yes| D{Status is PENDING_APPROVAL?}
    D -->|No| E[Return error: ADJUSTMENT_NOT_PENDING_APPROVAL]
    D -->|Yes| F[Update status to APPROVED]
    F --> G[Return updated adjustment]
```

## External Dependencies

- None

## Error Scenarios

- **ADJUSTMENT_NOT_FOUND**: Referenced adjustment does not exist
- **ADJUSTMENT_NOT_PENDING_APPROVAL**: Adjustment is not in PENDING_APPROVAL status

## Test Cases

- returns error when not found
- returns error when not pending
- approves adjustment
