chore(n8n-test): Apply v2 verification findings

Guard mockNode against unknown node names, reset captures per run, refuse
Code-node/sub-workflow capabilities with clear messages, pin nodes-base to its
release-train pairing (2.16.0 — avoids a nested second n8n-workflow copy), and
fix the mock-persistence wording.

packages/n8n-test/README.md

@@ -122,6 +122,10 @@ Feasibility is proven, but these are the edges the production version must own:
   interception point — mocking there would also catch non-HTTP-module clients.
 - **Speed is a non-issue.** The lazy loader brings node-type load to ~1s per
   process; the full demo suite runs in under 3s.
+- **(v2) Code nodes and sub-workflows need mocking.** Task-runner-backed nodes
+  (the Code node) and Execute Sub-workflow call engine capabilities a test
+  harness cannot provide; `runWorkflow` refuses them with a clear message —
+  `mockNode()` is the answer for both.
 - **(v2) Released-engine drift is the real prebake tax.** Three shims were
   needed to run on npm releases: `vitest-mock-extended`'s CJS build cannot be
   `require`d outside Vite's pipeline (hence the plain `additionalData` object);

packages/n8n-test/scripts/bundle.mjs

@@ -27,10 +27,12 @@ const externals = [
 // Pinned to current npm releases; bump deliberately, the engine API is the risk surface.
 // The @n8n helper pins MUST match what the released n8n-core depends on, or npm installs
 // a second copy and the DI container splits (`npm view n8n-core@<v> dependencies`).
+// nodes-base must be the release-train pairing for this core/workflow (check
+// `npm view n8n@<train> dependencies`) or it nests its own second n8n-workflow copy.
 const runtimeVersions = {
 	'n8n-core': '2.16.1',
 	'n8n-workflow': '2.16.0',
-	'n8n-nodes-base': '2.15.1',
+	'n8n-nodes-base': '2.16.0',
 	'@n8n/di': '0.10.0',
 	'@n8n/decorators': '1.16.0',
 };
@@ -112,8 +114,9 @@ export declare function runWorkflow(
 ): Promise<Record<string, unknown>>;
 
 /**
- * Replaces the named node's execution with a canned output for the next runWorkflow of
- * this workflow object. Multiple nodes may be mocked; last mock per node name wins.
+ * Replaces the named node's execution with a canned output for every subsequent
+ * runWorkflow of this workflow object, until clearNodeMocks() runs. Multiple nodes may
+ * be mocked; last mock per node name wins.
  */
 export declare function mockNode(
 	workflowJson: unknown,

packages/n8n-test/src/mock-node.ts

@@ -27,17 +27,23 @@ interface MockEntry {
 const registry = new Map<WorkflowJson, Map<string, MockEntry>>();
 
 /**
- * Replaces the named node's execution with a canned output for the next
- * {@link runWorkflow} of this workflow object. The JSON itself is never mutated.
- * Mocking the same node again replaces the previous mock (last one wins).
+ * Replaces the named node's execution with a canned output for every subsequent
+ * {@link runWorkflow} of this workflow object, until {@link clearNodeMocks} runs.
+ * The JSON itself is never mutated. Mocking the same node again replaces the
+ * previous mock (last one wins).
  *
- * The returned handle captures what the node received, for assertions.
+ * The returned handle captures what the node received on the latest run.
  */
 export function mockNode(
 	workflow: WorkflowJson,
 	nodeName: string,
 	output: IDataObject,
 ): MockedNodeHandle {
+	if (!workflow.nodes.some((node) => node.name === nodeName)) {
+		throw new UnexpectedError(
+			`Cannot mock node "${nodeName}": the workflow has no node with that name`,
+		);
+	}
 	let mocks = registry.get(workflow);
 	if (!mocks) {
 		mocks = new Map();
@@ -54,7 +60,10 @@ export function clearNodeMocks(): void {
 }
 
 export function getNodeMocks(workflow: WorkflowJson): Map<string, MockEntry> | undefined {
-	return registry.get(workflow);
+	const mocks = registry.get(workflow);
+	// A fresh run means fresh captures: a handle must never report a previous run's input.
+	if (mocks) for (const entry of mocks.values()) entry.capturedInput = undefined;
+	return mocks;
 }
 
 /**

packages/n8n-test/src/run-workflow.ts

@@ -126,6 +126,18 @@ export async function runWorkflow(
 		instanceBaseUrl: 'http://localhost',
 		variables: {},
 		currentNodeExecutionIndex: 0,
+		// Friendly refusals for engine capabilities a test harness cannot provide — without
+		// these, nodes fail with raw TypeErrors ("... is not a function").
+		executeWorkflow: () => {
+			throw new UnexpectedError(
+				'Sub-workflow execution is not supported by n8n-test — mock the node with mockNode() instead',
+			);
+		},
+		startRunnerTask: () => {
+			throw new UnexpectedError(
+				'Task-runner nodes (e.g. the Code node) are not supported by n8n-test — mock them with mockNode() instead',
+			);
+		},
 	} as unknown as IWorkflowExecuteAdditionalData;
 
 	const runExecutionData = createRunExecutionData({