Workflows: fix getting a workflow when such workflow was not yet created (#7520)

* fix getting a workflow when such workflow was not yet created

* Update .changeset/lovely-fireants-roll.md

Co-authored-by: Matt Silverlock <[email protected]>

* prettify

* cleanup

---------

Co-authored-by: Matt Silverlock <[email protected]>

Author: bruxodasilva

.changeset/lovely-fireants-roll.md

@@ -0,0 +1,5 @@
+---
+"@cloudflare/workflows-shared": patch
+---
+
+Fixed a bug in local development where fetching a Workflow instance by ID would return a Workflow status, even if that instance did not exist. This only impacted the `get()` method on the Worker bindings.

fixtures/import-npm/package-lock.json

@@ -83,4 +83,15 @@ describe("Workflows", () => {
 			output: [],
 		});
 	});
+
+	it("fails getting a workflow without creating it first", async ({
+		expect,
+	}) => {
+		await expect(
+			fetchJson(`http://${ip}:${port}/status?workflowName=anotherTest`)
+		).resolves.toMatchObject({
+			message: "instance.not_found",
+			name: "Error",
+		});
+	});
 });

fixtures/workflow/tests/index.test.ts

@@ -142,6 +142,10 @@ export class Engine extends DurableObject<Env> {
 		_accountId: number,
 		_instanceId: string
 	): Promise<InstanceStatus> {
+		if (this.accountId === undefined) {
+			throw new Error("stub not initialized");
+		}
+
 		const res = await this.ctx.storage.get<InstanceStatus>(ENGINE_STATUS_KEY);
 
 		// NOTE(lduarte): if status don't exist, means that engine is running for the first time, so we assume queued