Spawn node: place assets at runtime into the play copy, Spawner demo behavior

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tests/core/graph.test.ts

@@ -4,7 +4,7 @@ import { CommandStack } from '../../src/core/commands/CommandStack';
 import { AddNodeCommand, ConnectCommand, DisconnectCommand, RemoveNodeCommand, SetNodeParamCommand } from '../../src/core/commands/graphCommands';
 import { PlaceAssetCommand, SetParentCommand } from '../../src/core/commands/sceneObjectCommands';
 import { AddVariableCommand, RemoveVariableCommand, RenameVariableCommand } from '../../src/core/commands/variableCommands';
-import { type EntityHandle, GraphInterpreter, type NodeContext, allNodeDefs, portsCompatible } from '../../src/core/graph';
+import { type EntityHandle, type Graph, GraphInterpreter, type NodeContext, allNodeDefs, portsCompatible } from '../../src/core/graph';
 import type { BehaviorAsset } from '../../src/core/model/Asset';
 import { createEmptyProject } from '../../src/core/model/Project';
 import { deserializeProject, serializeProject } from '../../src/core/store/serialize';
@@ -32,6 +32,7 @@ function context(overrides: Partial<NodeContext> = {}): NodeContext & { logs: st
       return { blockedX: false, blockedY: false };
     },
     log: (m: string) => logs.push(m),
+    spawn: () => null,
     destroy: () => {},
     stop: () => { ctx.stopped = true; },
     ...overrides,
@@ -382,3 +383,41 @@ describe('behavior serialization', () => {
     expect(cleaned.graph.edges.length).toBe(behavior.graph.edges.length);
   });
 });
+
+describe('Spawn node', () => {
+  const graph: Graph = {
+    nodes: [
+      { id: 'start', type: 'OnStart', x: 0, y: 0, params: {} },
+      { id: 'spawn', type: 'Spawn', x: 0, y: 0, params: { asset: 'crate', x: 5, y: 7 } },
+      { id: 'log', type: 'Log', x: 0, y: 0, params: {} },
+    ],
+    edges: [
+      { id: 'e1', from: { node: 'start', port: 'exec' }, to: { node: 'spawn', port: 'exec' } },
+      { id: 'e2', from: { node: 'spawn', port: 'exec' }, to: { node: 'log', port: 'exec' } },
+      { id: 'e3', from: { node: 'spawn', port: 'object' }, to: { node: 'log', port: 'message' } },
+    ],
+  };
+
+  it('asks the context for a new instance at the inline position and outputs it', () => {
+    const calls: unknown[] = [];
+    const ctx = context({
+      spawn: (assetId, position, parent) => {
+        calls.push({ assetId, position, parent });
+        return entity('Crate', position.x);
+      },
+    });
+    new GraphInterpreter(graph).fire('OnStart', ctx);
+    expect(calls).toEqual([{ assetId: 'crate', position: { x: 5, y: 7, z: 0 }, parent: null }]);
+    expect(ctx.logs).toEqual(['Crate']); // the spawned object flowed into Log
+  });
+
+  it('logs a hint and continues when no asset is selected or the asset is unknown', () => {
+    const ctx = context({ spawn: () => null });
+    const noAsset: Graph = { ...graph, nodes: graph.nodes.map((n) => (n.id === 'spawn' ? { ...n, params: {} } : n)) };
+    new GraphInterpreter(noAsset).fire('OnStart', ctx);
+    expect(ctx.logs).toEqual(['Spawn: no asset selected', '']);
+    const ctx2 = context({ spawn: () => null });
+    new GraphInterpreter(graph).fire('OnStart', ctx2);
+    expect(ctx2.logs[0]).toBe('Spawn: asset crate not found');
+  });
+});