test: strengthen typing in promotionList tests

- Use `satisfies Partial<Omit<T, 'constructor'>>` for shape-checked mock
- Type mock param as NodeProperty instead of unknown
- Annotate test data with `satisfies ProxyWidgetsProperty`
- Document partial mock pattern in vitest-patterns.md

Amp-Thread-ID: https://ampcode.com/threads/T-019c5543-f50b-77a2-bca6-2549bdc15594
Co-authored-by: Amp <amp@ampcode.com>

docs/testing/vitest-patterns.md

@@ -61,6 +61,30 @@ vi.mock('@/services/myService', () => ({
 }))
 ```
 
+### Partial object mocks with `satisfies`
+
+When mocking a class instance with only the properties your test needs, use
+`satisfies Partial<Omit<T, 'constructor'>> as unknown as T`. This validates
+the mock's shape against the real type while allowing the incomplete cast.
+
+The `Omit<..., 'constructor'>` is needed because class types expose a
+`constructor` property whose type (`LGraphNodeConstructor`, etc.) conflicts
+with the plain object's `Function` constructor.
+
+```typescript
+// ✅ Shape-checked partial mock
+function mockSubgraphNode(proxyWidgets?: NodeProperty) {
+  return {
+    properties: { proxyWidgets }
+  } satisfies Partial<Omit<SubgraphNode, 'constructor'>> as unknown as SubgraphNode
+}
+
+// ❌ Unchecked — typos and shape mismatches slip through
+function mockSubgraphNode(proxyWidgets?: unknown): SubgraphNode {
+  return { properties: { proxyWidgets } } as unknown as SubgraphNode
+}
+```
+
 ### Configure mocks in tests
 
 ```typescript

src/core/graph/subgraph/promotionList.test.ts

@@ -1,11 +1,17 @@
 import { describe, expect, it } from 'vitest'
 
+import type { ProxyWidgetsProperty } from '@/core/schemas/proxyWidget'
+import type { NodeProperty } from '@/lib/litegraph/src/LGraphNode'
 import type { SubgraphNode } from '@/lib/litegraph/src/subgraph/SubgraphNode'
 
 import { getPromotionList } from './promotionList'
 
-function mockSubgraphNode(proxyWidgets?: unknown): SubgraphNode {
-  return { properties: { proxyWidgets } } as unknown as SubgraphNode
+function mockSubgraphNode(proxyWidgets?: NodeProperty) {
+  return {
+    properties: { proxyWidgets }
+  } satisfies Partial<
+    Omit<SubgraphNode, 'constructor'>
+  > as unknown as SubgraphNode
 }
 
 describe('getPromotionList', () => {
@@ -23,13 +29,13 @@ describe('getPromotionList', () => {
     const entries = [
       ['42', 'seed'],
       ['7', 'steps']
-    ]
+    ] satisfies ProxyWidgetsProperty
     const node = mockSubgraphNode(entries)
     expect(getPromotionList(node)).toEqual(entries)
   })
 
   it('handles string-serialized proxyWidgets (JSON)', () => {
-    const entries = [['42', 'seed']]
+    const entries = [['42', 'seed']] satisfies ProxyWidgetsProperty
     const node = mockSubgraphNode(JSON.stringify(entries))
     expect(getPromotionList(node)).toEqual(entries)
   })