feat(wrangler): introspect workflow with test harness

.changeset/sharp-workflows-wait.md

@@ -0,0 +1,19 @@
+---
+"@cloudflare/vitest-pool-workers": minor
+---
+
+Make Workflow introspector `get()` async
+
+The `introspectWorkflow(...).get()` method now returns a promise, so callers must await it:
+
+```ts
+const introspector = await introspectWorkflow(env.MY_WORKFLOW);
+
+// Before
+const instances = introspector.get();
+
+// After
+const instances = await introspector.get();
+```
+
+This aligns Workflow introspection with the shared implementation used by `createTestHarness()`.

.changeset/soft-workflows-smile.md

@@ -0,0 +1,25 @@
+---
+"miniflare": patch
+"wrangler": minor
+---
+
+Add Workflow introspection to `createTestHarness()`
+
+Worker handles can now introspect Workflow bindings by name, allowing tests to disable sleeps, mock step results, and wait for Workflow outcomes. Tests can introspect a known Workflow instance by ID or track instances created after introspection starts.
+
+```ts
+const harness = createTestHarness({
+	workers: [{ configPath: "./wrangler.json" }],
+});
+
+const worker = harness.getWorker();
+await using workflow = await worker.introspectWorkflow("MY_WORKFLOW");
+
+await workflow.modifyAll((modifier) =>
+	modifier.disableSleeps([{ name: "wait-for-approval" }])
+);
+
+const response = await worker.fetch("/start-workflow");
+const [instance] = await workflow.get();
+await instance.waitForStatus("complete");
+```

fixtures/vitest-pool-workers-examples/workflows/test/integration.test.ts

@@ -19,7 +19,7 @@ it("workflow should be able to reach the end and be successful", async ({
 
 	await exports.default.fetch(`https://mock-worker.local/moderate`);
 
-	const instances = introspector.get();
+	const instances = await introspector.get();
 	expect(instances.length).toBe(1);
 
 	// ASSERTIONS:
@@ -49,7 +49,7 @@ it("workflow batch should be able to reach the end and be successful", async ({
 
 		await exports.default.fetch(`https://mock-worker.local/moderate-batch`);
 
-		const instances = introspector.get();
+		const instances = await introspector.get();
 		expect(instances.length).toBe(3);
 
 		// ASSERTIONS:
@@ -86,7 +86,7 @@ describe("workflow instance lifecycle methods", () => {
 		);
 		const data = (await res.json()) as { id: string; details: unknown };
 
-		const instances = introspector.get();
+		const instances = await introspector.get();
 		expect(instances.length).toBe(1);
 		const instance = instances[0];
 
@@ -120,7 +120,7 @@ describe("workflow instance lifecycle methods", () => {
 		);
 		const data = (await res.json()) as { id: string; details: unknown };
 
-		const instances = introspector.get();
+		const instances = await introspector.get();
 		expect(instances.length).toBe(1);
 		const instance = instances[0];
 
@@ -155,7 +155,7 @@ describe("workflow instance lifecycle methods", () => {
 		);
 		const data = (await res.json()) as { id: string; details: unknown };
 
-		const instances = introspector.get();
+		const instances = await introspector.get();
 		expect(instances.length).toBe(1);
 		const instance = instances[0];
 

packages/miniflare/src/workers/workflows/wrapped-binding.worker.ts

@@ -2,6 +2,7 @@ import type {
 	WorkflowBinding,
 	WorkflowInstanceRestartOptions,
 } from "@cloudflare/workflows-shared/src/binding";
+import type { WorkflowIntrospectionOperation } from "@cloudflare/workflows-shared/src/types";
 
 class WorkflowImpl implements Workflow {
 	constructor(private binding: WorkflowBinding) {}
@@ -36,6 +37,25 @@ class WorkflowImpl implements Workflow {
 		return this.binding.unsafeGetBindingName();
 	}
 
+	async unsafeStartIntrospection(): Promise<string> {
+		return this.binding.unsafeStartIntrospection();
+	}
+
+	async unsafeStopIntrospection(sessionId: string): Promise<void> {
+		return this.binding.unsafeStopIntrospection(sessionId);
+	}
+
+	async unsafeSetIntrospectionOperations(
+		sessionId: string,
+		operations: WorkflowIntrospectionOperation[]
+	): Promise<void> {
+		return this.binding.unsafeSetIntrospectionOperations(sessionId, operations);
+	}
+
+	async unsafeGetIntrospectionInstances(sessionId: string): Promise<string[]> {
+		return this.binding.unsafeGetIntrospectionInstances(sessionId);
+	}
+
 	async unsafeAbort(instanceId: string, reason?: string): Promise<void> {
 		return this.binding.unsafeAbort(instanceId, reason);
 	}