Prompt Regression Testing Suite

Build a regression testing suite for prompt changes.

## Prompt Inventory
{{prompt_inventory}}

## Quality Metrics
{{quality_metrics}}

## CI/CD Requirements
{{cicd_requirements}}

Implement regression testing:

```python
class PromptRegressionSuite:
    def load_test_cases(self, prompt_id: str) -> List[TestCase]:
        """Load golden test cases"""
        pass
    
    def run_regression(self, old_prompt: str, new_prompt: str) -> RegressionReport:
        """
        Compare:
        - Output quality scores
        - Behavioral consistency
        - Latency impact
        - Token usage delta
        """
        pass
    
    def generate_diff_report(self, report: RegressionReport) -> str:
        """Human-readable comparison"""
        pass
```

Include:
- Golden dataset management
- Automated evaluation metrics
- Statistical significance testing
- CI pipeline integration