chore: import upstream snapshot with attribution

fixtures/create-test-harness-example/tests/playwright.test.ts

@@ -0,0 +1,107 @@
+import { test as base, expect } from "@playwright/test";
+import { http, HttpResponse } from "msw";
+import { setupServer, type SetupServerApi } from "msw/node";
+import { createTestHarness, type TestHarness } from "wrangler";
+
+type TestFixtures = {
+	reset: void;
+};
+
+type WorkerFixtures = {
+	network: SetupServerApi;
+	server: TestHarness;
+};
+
+const test = base.extend<TestFixtures, WorkerFixtures>({
+	network: [
+		async ({}, use) => {
+			const network = setupServer();
+			network.listen({ onUnhandledRequest: "error" });
+
+			await use(network);
+
+			network.close();
+		},
+		{ scope: "worker" },
+	],
+
+	server: [
+		async ({}, use) => {
+			const server = createTestHarness({
+				workers: [
+					// Playwright tests run against the Vite build output.
+					{ configPath: "./dist/web_worker/wrangler.json" },
+					{ configPath: "./dist/api_worker/wrangler.json" },
+				],
+			});
+
+			await server.listen();
+
+			await use(server);
+
+			await server.close();
+		},
+		{ scope: "worker" },
+	],
+
+	baseURL: async ({ server }, use) => {
+		const { url } = await server.listen();
+		await use(url.href);
+	},
+
+	reset: [
+		async ({ network, server }, use, testInfo) => {
+			await server.getWorker("api-worker").applyD1Migrations("DATABASE");
+
+			await use();
+
+			if (testInfo.status !== testInfo.expectedStatus) {
+				server.debug();
+			}
+
+			network.resetHandlers();
+			await server.reset();
+		},
+		{ auto: true },
+	],
+});
+
+test.describe("createTestHarness: Playwright setup", () => {
+	test("renders a user profile", async ({ page, network }) => {
+		network.use(
+			http.get("http://identity.example.com/profile/:id", ({ params }) => {
+				return HttpResponse.json({ id: params.id, name: "Ada" });
+			})
+		);
+
+		await page.goto("/users/123");
+
+		await expect(page.getByText("Profile: Ada")).toBeVisible();
+	});
+
+	test("renders a report generated by a scheduled handler", async ({
+		page,
+		network,
+		server,
+	}) => {
+		network.use(
+			http.get("http://identity.example.com/profile/:id", ({ params }) => {
+				return HttpResponse.json({ id: params.id, name: "Ada" });
+			})
+		);
+
+		const apiWorker = server.getWorker("api-worker");
+		await apiWorker.fetch("/v1/users/123");
+		await apiWorker.fetch("/v1/users/456");
+		await apiWorker.scheduled({
+			cron: "0 0 * * *",
+			scheduledTime: new Date("2026-05-29T00:00:00.000Z"),
+		});
+
+		await page.goto("/reports/2026-05-29");
+
+		await expect(
+			page.getByText("Daily report (2026-05-29): active users 123, 456")
+		).toBeVisible();
+	});
+});

fixtures/create-test-harness-example/tests/tsconfig.json

@@ -0,0 +1,14 @@
+{
+	"extends": "@cloudflare/workers-tsconfig/tsconfig.json",
+	"compilerOptions": {
+		"module": "esnext",
+		"noEmit": true,
+		"types": ["@cloudflare/workers-types", "node"]
+	},
+	"include": [
+		"../playwright.config.ts",
+		"../workers/*/worker-configuration.d.ts",
+		"**/*.ts"
+	],
+	"exclude": []
+}

fixtures/create-test-harness-example/tests/vitest.test.ts

@@ -0,0 +1,160 @@
+import { http, HttpResponse } from "msw";
+import { setupServer } from "msw/node";
+import {
+	afterAll,
+	afterEach,
+	beforeAll,
+	beforeEach,
+	describe,
+	test,
+} from "vitest";
+import { createTestHarness } from "wrangler";
+
+// Point each worker to the Wrangler config you want to test.
+const server = createTestHarness({
+	workers: [
+		{
+			configPath: "./workers/web/wrangler.jsonc",
+			bindingOverrides: { BROWSER: "mock-browser" },
+		},
+		{ configPath: "./workers/api/wrangler.jsonc" },
+		{ configPath: "./workers/mock-browser/wrangler.jsonc" },
+	],
+});
+
+// server.getWorker() would return the first Worker, but naming it makes it explicit.
+const webWorker = server.getWorker<
+	WebEnv,
+	typeof import("../workers/web/index")
+>("web-worker");
+const apiWorker = server.getWorker<
+	ApiEnv,
+	typeof import("../workers/api/index")
+>("api-worker");
+const mockBrowserWorker = server.getWorker<
+	unknown,
+	typeof import("../workers/mock-browser/index")
+>("mock-browser");
+
+// Workers started by createTestHarness route outbound fetches to globalThis.fetch().
+// You can use libraries like MSW to intercept those requests.
+const network = setupServer();
+
+describe("createTestHarness: Vitest setup", () => {
+	beforeAll(async () => {
+		network.listen({ onUnhandledRequest: "error" });
+		await server.listen();
+	});
+
+	beforeEach(async () => {
+		await apiWorker.applyD1Migrations("DATABASE");
+	});
+
+	afterAll(async () => {
+		network.close();
+		await server.close();
+	});
+
+	afterEach(async () => {
+		// Keep tests isolated while reusing the same running server.
+		network.resetHandlers();
+		await server.reset();
+	});
+
+	test("fetches the primary Worker with a relative URL", async ({ expect }) => {
+		// Relative URLs are dispatched to the primary Worker (the first one listed).
+		const response = await server.fetch("/");
+		expect(await response.text()).toBe("Hello World");
+	});
+
+	test("mocks outbound requests", async ({ expect }) => {
+		network.use(
+			http.get("http://identity.example.com/profile/:id", ({ params }) => {
+				return HttpResponse.json({ id: params.id, name: "Ada" });
+			})
+		);
+
+		const userResponse = await apiWorker.fetch("/v1/users/123");
+		expect(await userResponse.json()).toEqual({
+			id: "123",
+			name: "Ada",
+		});
+	});
+
+	test("overrides a platform binding with a mock Worker", async ({
+		expect,
+	}) => {
+		const apiEnv = await apiWorker.getEnv();
+		await apiEnv.DATABASE.prepare(
+			"INSERT INTO daily_reports (date, user_ids) VALUES (?, ?)"
+		)
+			.bind("2026-05-29", JSON.stringify(["123", "456"]))
+			.run();
+
+		const stubPng = Uint8Array.from([
+			137, 80, 78, 71, 13, 10, 26, 10, 109, 111, 99, 107,
+		]);
+		const mockBrowser = await mockBrowserWorker.getExport();
+		await mockBrowser.setScreenshot(Array.from(stubPng));
+
+		const response = await webWorker.fetch("/reports/2026-05-29.png");
+		expect(response.headers.get("content-type")).toBe("image/png");
+		expect(await response.bytes()).toEqual(stubPng);
+	});
+
+	test("dispatches requests using configured routes", async ({ expect }) => {
+		network.use(
+			http.get("http://identity.example.com/profile/:id", ({ params }) => {
+				return HttpResponse.json({ id: params.id, name: "Ada" });
+			})
+		);
+
+		// server.fetch() matches requests to workers based on routes.
+		const apiResponse = await server.fetch(
+			"http://api.example.com/v1/users/123"
+		);
+		expect(await apiResponse.json()).toEqual({
+			id: "123",
+			name: "Ada",
+		});
+
+		const webResponse = await server.fetch("http://example.com/users/123");
+		expect(await webResponse.text()).toBe("Profile: Ada");
+	});
+
+	test("runs scheduled jobs and stores the result", async ({ expect }) => {
+		network.use(
+			http.get("http://identity.example.com/profile/:id", ({ params }) => {
+				return HttpResponse.json({ id: params.id, name: "Ada" });
+			})
+		);
+
+		// Seed user data that the scheduled job will read to generate a report.
+		await apiWorker.fetch("/v1/users/123");
+		await apiWorker.fetch("/v1/users/456");
+
+		const initialResponse = await webWorker.fetch("/reports/2026-05-29");
+		expect(initialResponse.status).toBe(404);
+		expect(await initialResponse.text()).toBe("No report");
+
+		server.clearLogs();
+
+		expect(
+			await apiWorker.scheduled({
+				cron: "0 0 * * *",
+				scheduledTime: new Date("2026-05-29T00:00:00.000Z"),
+			})
+		).toEqual({ outcome: "ok", noRetry: false });
+		expect(server.getLogs()).toContainEqual(
+			expect.objectContaining({
+				level: "info",
+				message: "Generated daily report for 2026-05-29",
+			})
+		);
+
+		const webResponse = await webWorker.fetch("/reports/2026-05-29");
+		expect(await webResponse.text()).toBe(
+			"Daily report (2026-05-29): active users 123, 456"
+		);
+	});
+});