Function formatComparison

test/helpers/eval-store.ts:323–431

(c: ComparisonResult)

 * Format a ComparisonResult as a readable string.
 */
export function formatComparison(c: ComparisonResult): string {
  const lines: string[] = [];
  const ts = c.before_timestamp ? c.before_timestamp.replace('T', ' ').slice(0, 16) : 'unknown';
  lines.push(`\nvs previous: ${c.before_branch}/${c.deltas.length ? 'eval' : ''} (${ts})`);
  lines.push('─'.repeat(70));

  // Per-test deltas
  for (const d of c.deltas) {
    const arrow = d.status_change === 'improved' ? '↑' : d.status_change === 'regressed' ? '↓' : '=';
    const beforeStatus = d.before.passed ? 'PASS' : 'FAIL';
    const afterStatus = d.after.passed ? 'PASS' : 'FAIL';

    // Turns delta
    let turnsDelta = '';
    if (d.before.turns_used !== undefined && d.after.turns_used !== undefined) {
      const td = d.after.turns_used - d.before.turns_used;
      turnsDelta = ` ${d.before.turns_used}→${d.after.turns_used}t`;
      if (td !== 0) turnsDelta += `(${td > 0 ? '+' : ''}${td})`;
    } else if (d.after.turns_used !== undefined) {
      turnsDelta = ` ${d.after.turns_used}t`;
    }

    // Duration delta
    let durDelta = '';
    if (d.before.duration_ms !== undefined && d.after.duration_ms !== undefined) {
      const bs = Math.round(d.before.duration_ms / 1000);
      const as = Math.round(d.after.duration_ms / 1000);
      const dd = as - bs;
      durDelta = ` ${bs}→${as}s`;
      if (dd !== 0) durDelta += `(${dd > 0 ? '+' : ''}${dd})`;
    } else if (d.after.duration_ms !== undefined) {
      durDelta = ` ${Math.round(d.after.duration_ms / 1000)}s`;
    }

    let detail = '';
    if (d.before.detection_rate !== undefined || d.after.detection_rate !== undefined) {
      detail = ` ${d.before.detection_rate ?? '?'}→${d.after.detection_rate ?? '?'} det`;
    } else {
      const costBefore = d.before.cost_usd.toFixed(2);
      const costAfter = d.after.cost_usd.toFixed(2);
      detail = ` $${costBefore}→$${costAfter}`;
    }

    const name = d.name.length > 30 ? d.name.slice(0, 27) + '...' : d.name.padEnd(30);
    lines.push(`  ${name}  ${beforeStatus.padEnd(5)} → ${afterStatus.padEnd(5)}  ${arrow}${detail}${turnsDelta}${durDelta}`);
  }

  lines.push('─'.repeat(70));

  // Totals
  const parts: string[] = [];
  if (c.improved > 0) parts.push(`${c.improved} improved`);
  if (c.regressed > 0) parts.push(`${c.regressed} regressed`);
  if (c.unchanged > 0) parts.push(`${c.unchanged} unchanged`);
  lines.push(`  Status: ${parts.join(', ')}`);

  const costSign = c.total_cost_delta >= 0 ? '+' : '';
  lines.push(`  Cost:   ${costSign}$${c.total_cost_delta.toFixed(2)}`);