feat: add useSubagentCostRollup hook

2026-08-24 14:50:34 +01:00
parent 9ae30bd412
commit 7fde0a01b5
2 changed files with 100 additions and 0 deletions
@@ -0,0 +1,46 @@
+import { describe, expect, test } from 'bun:test';
+import type { Session } from '@opencode-ai/sdk/v2';
+import { computeRollup } from './useSubagentCostRollup';
+
+function makeSession(id: string, cost: number, parentID?: string): Session {
+  return { id, cost, parentID } as unknown as Session;
+}
+
+const sessions: Session[] = [
+  makeSession('root', 1),
+  makeSession('a', 2, 'root'),
+  makeSession('b', 3, 'root'),
+  makeSession('a1', 5, 'a'),
+];
+
+describe('computeRollup', () => {
+  test('sums own cost plus every descendant', () => {
+    const result = computeRollup(sessions, 'root');
+    expect(result.totalCost).toBe(11);
+    expect(result.subagentCount).toBe(3);
+  });
+
+  test('maps each direct child to its own subtree cost', () => {
+    const result = computeRollup(sessions, 'root');
+    expect(result.perChildCost.get('a')).toBe(7);
+    expect(result.perChildCost.get('b')).toBe(3);
+  });
+
+  test('returns null total for a null sessionId', () => {
+    const result = computeRollup(sessions, null);
+    expect(result.totalCost).toBeNull();
+    expect(result.subagentCount).toBe(0);
+  });
+
+  test('returns null total for an unknown sessionId', () => {
+    const result = computeRollup(sessions, 'missing');
+    expect(result.totalCost).toBeNull();
+  });
+
+  test('sum of perChildCost plus root cost equals totalCost', () => {
+    const result = computeRollup(sessions, 'root');
+    const childSum = Array.from(result.perChildCost.values()).reduce((sum, v) => sum + v, 0);
+    const rootOwnCost = 1;
+    expect(childSum + rootOwnCost).toBe(result.totalCost);
+  });
+});