diff --git a/packages/astro/test/test-utils.js b/packages/astro/test/test-utils.js
index 5cb51db93982..6cc8081b3e04 100644
--- a/packages/astro/test/test-utils.js
+++ b/packages/astro/test/test-utils.js
@@ -27,7 +27,14 @@ process.env.ASTRO_TELEMETRY_DISABLED = true;
  * @typedef {import('../src/cli/check/index').CheckPayload} CheckPayload
  * @typedef {import('http').IncomingMessage} NodeRequest
  * @typedef {import('http').ServerResponse} NodeResponse
+ * `RequestHandler` is defined in `@astrojs/node` so we cannot import it directly.
+ * See https://github.com/withastro/astro/blob/astro@6.0.0/packages/integrations/node/src/types.ts#L44-L50
+ * @typedef {(req: NodeRequest, res: NodeResponse, next?: (err?: unknown) => void, locals?: object) => void | Promise<void>} RequestHandler
  *
+ * `startServer` is defined in `@astrojs/node` so we cannot import it directly.
+ * See https://github.com/withastro/astro/blob/astro@6.0.0/packages/integrations/node/src/server.ts#L21
+ * @typedef {PreviewServer & { server: import('http').Server }} AdapterServer
+ * @typedef {() => ({server: AdapterServer, stop: Promise<void>})} AdapterStartServer
  *
  * @typedef {Object} Fixture
  * @property {(extraInlineConfig?: Parameters<typeof build>[0], options?: Parameters<typeof build>[1]) => Promise<void>} build
@@ -43,7 +50,8 @@ process.env.ASTRO_TELEMETRY_DISABLED = true;
  * @property {() => Promise<void>} clean
  * @property {(streaming?: boolean) => Promise<App>} loadTestAdapterApp
  * @property {(streaming?: boolean) => Promise<App>} loadSelfAdapterApp
- * @property {() => Promise<(req: NodeRequest, res: NodeResponse) => void>} loadNodeAdapterHandler
+ * @property {() => Promise<{ handler: RequestHandler; startServer: AdapterStartServer }>} loadAdapterEntryModule
+ * @property {() => Promise<RequestHandler>} loadNodeAdapterHandler
  * @property {(timeout?: number) => Promise<void>} onNextDataStoreChange
  * @property {typeof check} check
  * @property {typeof sync} sync
diff --git a/packages/astro/test/units/test-utils.ts b/packages/astro/test/units/test-utils.ts
index 519a1e6d6dbd..fb8ee5b13f15 100644
--- a/packages/astro/test/units/test-utils.ts
+++ b/packages/astro/test/units/test-utils.ts
@@ -1,5 +1,6 @@
 import { EventEmitter } from 'node:events';
 import { fileURLToPath } from 'node:url';
+import type { IncomingMessage, ServerResponse } from 'node:http';
 import { createFixture as _createFixture, type FileTree } from 'fs-fixture';
 import httpMocks from 'node-mocks-http';
 import { getDefaultClientDirectives } from '../../dist/core/client-directive/index.js';
@@ -39,10 +40,10 @@ export async function createFixture(tree: FileTree) {
 }
 
 export function createRequestAndResponse(reqOptions: httpMocks.RequestOptions = {}) {
-	const req = httpMocks.createRequest(reqOptions);
+	const req: IncomingMessage = httpMocks.createRequest(reqOptions);
 	req.headers.host ||= 'localhost';
 
-	const res = httpMocks.createResponse({
+	const res: ServerResponse<IncomingMessage> = httpMocks.createResponse({
 		eventEmitter: EventEmitter,
 		req,
 	});
diff --git a/packages/integrations/node/package.json b/packages/integrations/node/package.json
index 6a2d98e91fe2..e07cf38ff22a 100644
--- a/packages/integrations/node/package.json
+++ b/packages/integrations/node/package.json
@@ -30,7 +30,7 @@
     "dev": "astro-scripts dev \"src/**/*.ts\"",
     "build": "astro-scripts build \"src/**/*.ts\" && tsc",
     "build:ci": "astro-scripts build \"src/**/*.ts\"",
-    "test": "astro-scripts test \"test/**/*.test.js\" \"test/**/*.test.ts\"",
+    "test": "astro-scripts test \"test/**/*.test.ts\"",
     "typecheck:tests": "tsc --build tsconfig.test.json"
   },
   "dependencies": {
@@ -44,6 +44,7 @@
   "devDependencies": {
     "@fastify/middie": "^9.1.0",
     "@fastify/static": "^9.0.0",
+    "@types/express": "^5.0.6",
     "@types/node": "^22.10.6",
     "@types/send": "^1.2.1",
     "@types/server-destroy": "^1.0.4",
diff --git a/packages/integrations/node/test/api-route.test.js b/packages/integrations/node/test/api-route.test.ts
similarity index 85%
rename from packages/integrations/node/test/api-route.test.js
rename to packages/integrations/node/test/api-route.test.ts
index 05cdcd637bdf..26e26d0fe8bc 100644
--- a/packages/integrations/node/test/api-route.test.js
+++ b/packages/integrations/node/test/api-route.test.ts
@@ -1,16 +1,14 @@
 import * as assert from 'node:assert/strict';
 import crypto from 'node:crypto';
 import { after, before, describe, it } from 'node:test';
+import type { PreviewServer } from '../../../astro/src/types/public/preview.js';
 import nodejs from '../dist/index.js';
-import { createRequestAndResponse, loadFixture } from './test-utils.js';
+import { createRequestAndResponse, type Fixture, loadFixture } from './test-utils.ts';
 
 describe('API routes', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	/** @type {import('../../../astro/src/types/public/preview.js').PreviewServer} */
-	let previewServer;
-	/** @type {URL} */
-	let baseUri;
+	let fixture: Fixture;
+	let previewServer: PreviewServer;
+	let baseUri: URL;
 
 	before(async () => {
 		fixture = await loadFixture({
@@ -26,7 +24,7 @@ describe('API routes', () => {
 	after(() => previewServer.stop());
 
 	it('Can get the request body', async () => {
-		const { handler } = await import('./fixtures/api-route/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 		const { req, res, done } = createRequestAndResponse({
 			method: 'POST',
 			url: '/recipes',
@@ -48,7 +46,7 @@ describe('API routes', () => {
 	});
 
 	it('Can get binary data', async () => {
-		const { handler } = await import('./fixtures/api-route/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 
 		const { req, res, done } = createRequestAndResponse({
 			method: 'POST',
@@ -67,7 +65,7 @@ describe('API routes', () => {
 	});
 
 	it('Can post large binary data', async () => {
-		const { handler } = await import('./fixtures/api-route/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 
 		const { req, res, done } = createRequestAndResponse({
 			method: 'POST',
@@ -76,7 +74,7 @@ describe('API routes', () => {
 
 		handler(req, res);
 
-		let expectedDigest = null;
+		let expectedDigest: Buffer | null = null;
 		req.once('async_iterator', () => {
 			// Send 256MB of garbage data in 256KB chunks. This should be fast (< 1sec).
 			let remainingBytes = 256 * 1024 * 1024;
@@ -96,11 +94,11 @@ describe('API routes', () => {
 		});
 
 		const [out] = await done;
-		assert.deepEqual(new Uint8Array(out.buffer), new Uint8Array(expectedDigest));
+		assert.deepEqual(new Uint8Array(out.buffer), new Uint8Array(expectedDigest!));
 	});
 
 	it('Can bail on streaming', async () => {
-		const { handler } = await import('./fixtures/api-route/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 		const { req, res, done } = createRequestAndResponse({
 			url: '/streaming',
 		});
diff --git a/packages/integrations/node/test/assets.test.js b/packages/integrations/node/test/assets.test.ts
similarity index 88%
rename from packages/integrations/node/test/assets.test.js
rename to packages/integrations/node/test/assets.test.ts
index c6159c863a0e..e7682ef7b65e 100644
--- a/packages/integrations/node/test/assets.test.js
+++ b/packages/integrations/node/test/assets.test.ts
@@ -1,14 +1,14 @@
 import * as assert from 'node:assert/strict';
 import { after, before, describe, it } from 'node:test';
+import { fileURLToPath } from 'node:url';
+import type { PreviewServer } from '../../../astro/src/types/public/preview.js';
 import * as cheerio from 'cheerio';
 import nodejs from '../dist/index.js';
-import { loadFixture } from './test-utils.js';
-import { fileURLToPath } from 'node:url';
+import { type Fixture, loadFixture } from './test-utils.ts';
 
 describe('Assets', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let devPreview;
+	let fixture: Fixture;
+	let devPreview: PreviewServer;
 
 	before(async () => {
 		const root = new URL('./fixtures/image/', import.meta.url);
@@ -39,7 +39,7 @@ describe('Assets', () => {
 		const $ = cheerio.load(html);
 
 		// Fetch the asset
-		const fileURL = $('a').attr('href');
+		const fileURL = $('a').attr('href')!;
 		response = await fixture.fetch(fileURL);
 		cacheControl = response.headers.get('cache-control');
 		assert.equal(cacheControl, 'public, max-age=31536000, immutable');
@@ -50,7 +50,7 @@ describe('Assets', () => {
 		let response = await fixture.fetch('/text-file');
 		const html = await response.text();
 		const $ = cheerio.load(html);
-		const fileURL = $('a').attr('href');
+		const fileURL = $('a').attr('href')!;
 
 		// Send a request with a malformed If-Match header that won't match the ETag
 		response = await fixture.fetch(fileURL, {
diff --git a/packages/integrations/node/test/bad-urls.test.js b/packages/integrations/node/test/bad-urls.test.ts
similarity index 88%
rename from packages/integrations/node/test/bad-urls.test.js
rename to packages/integrations/node/test/bad-urls.test.ts
index 2e3e3ad28c18..fc45bef3fa4a 100644
--- a/packages/integrations/node/test/bad-urls.test.js
+++ b/packages/integrations/node/test/bad-urls.test.ts
@@ -1,12 +1,12 @@
 import * as assert from 'node:assert/strict';
 import { after, before, describe, it } from 'node:test';
+import type { PreviewServer } from '../../../astro/src/types/public/preview.js';
 import nodejs from '../dist/index.js';
-import { loadFixture } from './test-utils.js';
+import { type Fixture, loadFixture } from './test-utils.ts';
 
 describe('Bad URLs', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let devPreview;
+	let fixture: Fixture;
+	let devPreview: PreviewServer;
 
 	before(async () => {
 		fixture = await loadFixture({
diff --git a/packages/integrations/node/test/encoded.test.js b/packages/integrations/node/test/encoded.test.ts
similarity index 74%
rename from packages/integrations/node/test/encoded.test.js
rename to packages/integrations/node/test/encoded.test.ts
index 4fc97cf7fd09..657119e6d0b2 100644
--- a/packages/integrations/node/test/encoded.test.js
+++ b/packages/integrations/node/test/encoded.test.ts
@@ -1,11 +1,10 @@
 import * as assert from 'node:assert/strict';
 import { before, describe, it } from 'node:test';
 import nodejs from '../dist/index.js';
-import { createRequestAndResponse, loadFixture } from './test-utils.js';
+import { createRequestAndResponse, type Fixture, loadFixture } from './test-utils.ts';
 
 describe('Encoded Pathname', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
+	let fixture: Fixture;
 
 	before(async () => {
 		fixture = await loadFixture({
@@ -17,7 +16,7 @@ describe('Encoded Pathname', () => {
 	});
 
 	it('Can get an Astro file', async () => {
-		const { handler } = await import('./fixtures/encoded/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 		const { req, res, text } = createRequestAndResponse({
 			url: '/什么',
 		});
@@ -30,7 +29,7 @@ describe('Encoded Pathname', () => {
 	});
 
 	it('Can get a Markdown file', async () => {
-		const { handler } = await import('./fixtures/encoded/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 
 		const { req, res, text } = createRequestAndResponse({
 			url: '/blog/什么',
diff --git a/packages/integrations/node/test/errors.test.js b/packages/integrations/node/test/errors.test.ts
similarity index 73%
rename from packages/integrations/node/test/errors.test.js
rename to packages/integrations/node/test/errors.test.ts
index 99aff386bf00..c9b7fb92d8ea 100644
--- a/packages/integrations/node/test/errors.test.js
+++ b/packages/integrations/node/test/errors.test.ts
@@ -1,12 +1,11 @@
 import assert from 'node:assert/strict';
-import { after, before, describe, it } from 'node:test';
+import { before, describe, it } from 'node:test';
 import * as cheerio from 'cheerio';
 import nodejs from '../dist/index.js';
-import { loadFixture } from './test-utils.js';
+import { type Fixture, loadFixture } from './test-utils.ts';
 
 describe('Errors', () => {
-	/** @type {import('./test-utils.js').Fixture} */
-	let fixture;
+	let fixture: Fixture;
 
 	before(async () => {
 		fixture = await loadFixture({
@@ -16,15 +15,6 @@ describe('Errors', () => {
 		});
 		await fixture.build();
 	});
-	let devPreview;
-
-	// The two tests that need the server to run are skipped
-	// before(async () => {
-	//    devPreview = await fixture.preview();
-	// });
-	after(async () => {
-		await devPreview?.stop();
-	});
 
 	it('rejected promise in template', {
 		skip: true,
@@ -43,9 +33,8 @@ describe('Errors', () => {
 	}, async () => {
 		const result = ['<!DOCTYPE html><h1>Astro</h1> 1', 'Internal server error'];
 
-		/** @type {Response} */
-		const res = await fixture.fetch('/generator');
-		const reader = res.body.getReader();
+		const res: Response = await fixture.fetch('/generator');
+		const reader = res.body!.getReader();
 		const decoder = new TextDecoder();
 		const chunk1 = await reader.read();
 		const chunk2 = await reader.read();
diff --git a/packages/integrations/node/test/headers.test.js b/packages/integrations/node/test/headers.test.ts
similarity index 92%
rename from packages/integrations/node/test/headers.test.js
rename to packages/integrations/node/test/headers.test.ts
index 15f52a434d25..e9a5faa9c353 100644
--- a/packages/integrations/node/test/headers.test.js
+++ b/packages/integrations/node/test/headers.test.ts
@@ -1,12 +1,11 @@
 import * as assert from 'node:assert/strict';
 import { before, describe, it } from 'node:test';
 import nodejs from '../dist/index.js';
-import { createRequestAndResponse, loadFixture } from './test-utils.js';
+import { createRequestAndResponse, type Fixture, loadFixture } from './test-utils.ts';
 
-describe('Node Adapter Headers', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
+let fixture: Fixture;
 
+describe('Node Adapter Headers', () => {
 	describe('streaming', () => {
 		before(async () => {
 			fixture = await loadFixture({
@@ -131,7 +130,7 @@ describe('Node Adapter Headers', () => {
 
 		// TODO: needs e2e tests to check real headers
 		it('sends several chunks', async () => {
-			const { handler } = await import('./fixtures/headers/dist/server/entry.mjs');
+			const handler = await fixture.loadNodeAdapterHandler();
 
 			const { req, res, done } = createRequestAndResponse({
 				method: 'GET',
@@ -159,7 +158,7 @@ describe('Node Adapter Headers', () => {
 
 		// TODO: needs e2e tests to check real headers
 		it('sends a single chunk', async () => {
-			const { handler } = await import('./fixtures/headers/dist/server/entry.mjs?cachebust=0');
+			const handler = await fixture.loadNodeAdapterHandler();
 
 			const { req, res, done } = createRequestAndResponse({
 				method: 'GET',
@@ -176,8 +175,8 @@ describe('Node Adapter Headers', () => {
 	});
 });
 
-async function runTest(url, expectedHeaders) {
-	const { handler } = await import('./fixtures/headers/dist/server/entry.mjs');
+async function runTest(url: string, expectedHeaders: Record<string, string | string[]>) {
+	const handler = await fixture.loadNodeAdapterHandler();
 
 	const { req, res, done } = createRequestAndResponse({
 		method: 'GET',
diff --git a/packages/integrations/node/test/image.test.js b/packages/integrations/node/test/image.test.ts
similarity index 96%
rename from packages/integrations/node/test/image.test.js
rename to packages/integrations/node/test/image.test.ts
index 0426a7605c0f..f6d4389423f5 100644
--- a/packages/integrations/node/test/image.test.js
+++ b/packages/integrations/node/test/image.test.ts
@@ -1,16 +1,16 @@
 import * as assert from 'node:assert/strict';
 import { cp, rm } from 'node:fs/promises';
 import { after, before, describe, it } from 'node:test';
+import { fileURLToPath } from 'node:url';
+import type { PreviewServer } from '../../../astro/src/types/public/preview.js';
 import { inferRemoteSize } from 'astro/assets/utils/inferRemoteSize.js';
 import * as cheerio from 'cheerio';
 import nodejs from '../dist/index.js';
-import { loadFixture } from './test-utils.js';
-import { fileURLToPath } from 'node:url';
+import { type Fixture, loadFixture } from './test-utils.ts';
 
 describe('Image endpoint', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let devPreview;
+	let fixture: Fixture;
+	let devPreview: PreviewServer;
 
 	before(async () => {
 		const root = new URL('./fixtures/image/', import.meta.url);
diff --git a/packages/integrations/node/test/locals.test.js b/packages/integrations/node/test/locals.test.ts
similarity index 78%
rename from packages/integrations/node/test/locals.test.js
rename to packages/integrations/node/test/locals.test.ts
index b8e3ed40fc4b..d588d4ac3e69 100644
--- a/packages/integrations/node/test/locals.test.js
+++ b/packages/integrations/node/test/locals.test.ts
@@ -1,11 +1,10 @@
 import * as assert from 'node:assert/strict';
 import { before, describe, it } from 'node:test';
 import nodejs from '../dist/index.js';
-import { createRequestAndResponse, loadFixture } from './test-utils.js';
+import { createRequestAndResponse, type Fixture, loadFixture } from './test-utils.ts';
 
 describe('API routes', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
+	let fixture: Fixture;
 
 	before(async () => {
 		fixture = await loadFixture({
@@ -17,7 +16,7 @@ describe('API routes', () => {
 	});
 
 	it('Can use locals added by node middleware', async () => {
-		const { handler } = await import('./fixtures/locals/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 		const { req, res, text } = createRequestAndResponse({
 			url: '/from-node-middleware',
 		});
@@ -33,11 +32,12 @@ describe('API routes', () => {
 	});
 
 	it('Throws an error when provided non-objects as locals', async () => {
-		const { handler } = await import('./fixtures/locals/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 		const { req, res, done } = createRequestAndResponse({
 			url: '/from-node-middleware',
 		});
 
+		// @ts-expect-error - intentionally passing a non-object to test error handling
 		handler(req, res, undefined, 'locals');
 		req.send();
 
@@ -46,7 +46,7 @@ describe('API routes', () => {
 	});
 
 	it('Can use locals added by astro middleware', async () => {
-		const { handler } = await import('./fixtures/locals/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 
 		const { req, res, text } = createRequestAndResponse({
 			url: '/from-astro-middleware',
@@ -61,7 +61,7 @@ describe('API routes', () => {
 	});
 
 	it('Can access locals in API', async () => {
-		const { handler } = await import('./fixtures/locals/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 		const { req, res, done } = createRequestAndResponse({
 			method: 'POST',
 			url: '/api',
diff --git a/packages/integrations/node/test/node-middleware-listener-cleanup.test.js b/packages/integrations/node/test/node-middleware-listener-cleanup.test.ts
similarity index 82%
rename from packages/integrations/node/test/node-middleware-listener-cleanup.test.js
rename to packages/integrations/node/test/node-middleware-listener-cleanup.test.ts
index 2e3d3adfed5d..5684b426a7cd 100644
--- a/packages/integrations/node/test/node-middleware-listener-cleanup.test.js
+++ b/packages/integrations/node/test/node-middleware-listener-cleanup.test.ts
@@ -3,14 +3,13 @@ import { after, before, describe, it } from 'node:test';
 import { fileURLToPath } from 'node:url';
 import fastifyMiddie from '@fastify/middie';
 import fastifyStatic from '@fastify/static';
-import Fastify from 'fastify';
+import Fastify, { type FastifyInstance } from 'fastify';
 import nodejs from '../dist/index.js';
-import { loadFixture } from './test-utils.js';
+import { type Fixture, loadFixture } from './test-utils.ts';
 
 describe('Node middleware socket listener cleanup', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let server;
+	let fixture: Fixture;
+	let server: FastifyInstance;
 
 	before(async () => {
 		fixture = await loadFixture({
@@ -43,7 +42,7 @@ describe('Node middleware socket listener cleanup', () => {
 		});
 
 		let listenerWarningEmitted = false;
-		const warningListener = (warning) => {
+		const warningListener = (warning: Error) => {
 			if (warning.name === 'MaxListenersExceededWarning') {
 				listenerWarningEmitted = true;
 			}
@@ -54,6 +53,7 @@ describe('Node middleware socket listener cleanup', () => {
 			// Make multiple back-to-back requests to a static page
 			for (let i = 0; i < 30; i++) {
 				const response = await fetch('http://localhost:8890', {
+					// @ts-expect-error: it seems that Node.js `fetch` doesn't accept `agent` here. Should we use dispatcher instead? https://stackoverflow.com/a/76069981
 					agent,
 					headers: {
 						Connection: 'keep-alive',
diff --git a/packages/integrations/node/test/node-middleware.test.js b/packages/integrations/node/test/node-middleware.test.ts
similarity index 93%
rename from packages/integrations/node/test/node-middleware.test.js
rename to packages/integrations/node/test/node-middleware.test.ts
index 128837c31fd2..cef931d083d9 100644
--- a/packages/integrations/node/test/node-middleware.test.js
+++ b/packages/integrations/node/test/node-middleware.test.ts
@@ -1,3 +1,4 @@
+import type { Server } from 'node:http';
 import * as assert from 'node:assert/strict';
 import { after, before, describe, it } from 'node:test';
 import { fileURLToPath } from 'node:url';
@@ -5,18 +6,13 @@ import fastifyMiddie from '@fastify/middie';
 import fastifyStatic from '@fastify/static';
 import * as cheerio from 'cheerio';
 import express from 'express';
-import Fastify from 'fastify';
+import Fastify, { type FastifyInstance } from 'fastify';
 import nodejs from '../dist/index.js';
-import { loadFixture, waitServerListen } from './test-utils.js';
-
-/**
- * @typedef {import('../../../astro/test/test-utils').Fixture} Fixture
- */
+import { type Fixture, loadFixture, waitServerListen, type AdapterServer } from './test-utils.ts';
 
 describe('behavior from middleware, standalone', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let server;
+	let fixture: Fixture;
+	let server: AdapterServer;
 
 	before(async () => {
 		fixture = await loadFixture({
@@ -52,9 +48,8 @@ describe('behavior from middleware, standalone', () => {
 });
 
 describe('behavior from middleware, middleware with express', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let server;
+	let fixture: Fixture;
+	let server: Server;
 
 	before(async () => {
 		fixture = await loadFixture({
@@ -134,9 +129,8 @@ describe('behavior from middleware, middleware with express', () => {
 });
 
 describe('behavior from middleware, middleware with fastify', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let server;
+	let fixture: Fixture;
+	let server: FastifyInstance;
 
 	before(async () => {
 		fixture = await loadFixture({
@@ -216,9 +210,8 @@ describe('behavior from middleware, middleware with fastify', () => {
 // the Node adapter in middleware mode can identify them as static files and NOT
 // match them against catch-all routes.
 describe('middleware with fastify and catch-all route: SSR assets in manifest', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let server;
+	let fixture: Fixture;
+	let server: FastifyInstance;
 
 	before(async () => {
 		fixture = await loadFixture({
diff --git a/packages/integrations/node/test/prerender-404-500.test.js b/packages/integrations/node/test/prerender-404-500.test.ts
similarity index 96%
rename from packages/integrations/node/test/prerender-404-500.test.js
rename to packages/integrations/node/test/prerender-404-500.test.ts
index d873064ae090..c2b41fec2d50 100644
--- a/packages/integrations/node/test/prerender-404-500.test.js
+++ b/packages/integrations/node/test/prerender-404-500.test.ts
@@ -2,16 +2,11 @@ import * as assert from 'node:assert/strict';
 import { after, before, describe, it } from 'node:test';
 import * as cheerio from 'cheerio';
 import nodejs from '../dist/index.js';
-import { loadFixture, waitServerListen } from './test-utils.js';
-
-/**
- * @typedef {import('../../../astro/test/test-utils').Fixture} Fixture
- */
+import { type Fixture, loadFixture, waitServerListen, type AdapterServer } from './test-utils.ts';
 
 describe('Prerender 404', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let server;
+	let fixture: Fixture;
+	let server: AdapterServer;
 
 	describe('With base', async () => {
 		before(async () => {
@@ -155,9 +150,8 @@ describe('Prerender 404', () => {
 });
 
 describe('Hybrid 404', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let server;
+	let fixture: Fixture;
+	let server: AdapterServer;
 
 	describe('With base', async () => {
 		before(async () => {
diff --git a/packages/integrations/node/test/prerender.test.js b/packages/integrations/node/test/prerender.test.ts
similarity index 97%
rename from packages/integrations/node/test/prerender.test.js
rename to packages/integrations/node/test/prerender.test.ts
index a56828c8609f..9a873ab0a3b6 100644
--- a/packages/integrations/node/test/prerender.test.js
+++ b/packages/integrations/node/test/prerender.test.ts
@@ -2,16 +2,17 @@ import * as assert from 'node:assert/strict';
 import { after, before, describe, it } from 'node:test';
 import * as cheerio from 'cheerio';
 import nodejs from '../dist/index.js';
-import { loadFixture, waitServerListen } from './test-utils.js';
-
-/**
- * @typedef {import('../../../astro/test/test-utils').Fixture} Fixture
- */
+import {
+	type Fixture,
+	loadFixture,
+	waitServerListen,
+	type AdapterServer,
+	type DevServer,
+} from './test-utils.ts';
 
 describe('Prerendering', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let server;
+	let fixture: Fixture;
+	let server: AdapterServer;
 
 	describe('With base', async () => {
 		before(async () => {
@@ -223,7 +224,7 @@ describe('Prerendering', () => {
 	});
 
 	describe('Dev', () => {
-		let devServer;
+		let devServer: DevServer;
 
 		before(async () => {
 			fixture = await loadFixture({
@@ -260,9 +261,8 @@ describe('Prerendering', () => {
 });
 
 describe('Hybrid rendering', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let server;
+	let fixture: Fixture;
+	let server: AdapterServer;
 
 	describe('With base', () => {
 		before(async () => {
diff --git a/packages/integrations/node/test/prerendered-error-page-fetch.test.js b/packages/integrations/node/test/prerendered-error-page-fetch.test.ts
similarity index 77%
rename from packages/integrations/node/test/prerendered-error-page-fetch.test.js
rename to packages/integrations/node/test/prerendered-error-page-fetch.test.ts
index b66482b85595..9fb6c6110f89 100644
--- a/packages/integrations/node/test/prerendered-error-page-fetch.test.js
+++ b/packages/integrations/node/test/prerendered-error-page-fetch.test.ts
@@ -1,18 +1,14 @@
-// @ts-check
 import * as assert from 'node:assert/strict';
 import { after, before, describe, it } from 'node:test';
+import type { PreviewServer } from '../../../astro/src/types/public/preview.js';
 import node from '../dist/index.js';
-import { loadFixture } from './test-utils.js';
+import { type Fixture, loadFixture } from './test-utils.ts';
 
 describe('prerenderedErrorPageFetch', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	/** @type {import('astro').PreviewServer} */
-	let devPreview;
-	/** @type {typeof globalThis.fetch} */
-	let originalFetch;
-	/** @type {Array<string>} */
-	let urls;
+	let fixture: Fixture;
+	let devPreview: PreviewServer;
+	let originalFetch: typeof globalThis.fetch;
+	let urls: Array<string> = [];
 
 	before(async () => {
 		fixture = await loadFixture({
@@ -20,11 +16,10 @@ describe('prerenderedErrorPageFetch', () => {
 			adapter: node({ mode: 'standalone' }),
 		});
 		await fixture.clean();
-		await fixture.build({});
-		devPreview = await fixture.preview({});
+		await fixture.build();
+		devPreview = await fixture.preview();
 		originalFetch = globalThis.fetch;
 		globalThis.fetch = (...args) => {
-			urls ??= [];
 			if (typeof args[0] === 'string') {
 				urls.push(args[0]);
 			}
diff --git a/packages/integrations/node/test/preview-headers.test.js b/packages/integrations/node/test/preview-headers.test.ts
similarity index 80%
rename from packages/integrations/node/test/preview-headers.test.js
rename to packages/integrations/node/test/preview-headers.test.ts
index 3fd9d0508d6e..449d9657b4c3 100644
--- a/packages/integrations/node/test/preview-headers.test.js
+++ b/packages/integrations/node/test/preview-headers.test.ts
@@ -1,12 +1,12 @@
 import * as assert from 'node:assert/strict';
 import { after, before, describe, it } from 'node:test';
+import type { PreviewServer } from '../../../astro/src/types/public/preview.js';
 import nodejs from '../dist/index.js';
-import { loadFixture } from './test-utils.js';
+import { type Fixture, loadFixture } from './test-utils.ts';
 
 describe('Astro preview headers', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let devPreview;
+	let fixture: Fixture;
+	let devPreview: PreviewServer;
 	const headers = {
 		astro: 'test',
 	};
diff --git a/packages/integrations/node/test/preview-host.test.js b/packages/integrations/node/test/preview-host.test.ts
similarity index 97%
rename from packages/integrations/node/test/preview-host.test.js
rename to packages/integrations/node/test/preview-host.test.ts
index fec925e677f3..f601fc235772 100644
--- a/packages/integrations/node/test/preview-host.test.js
+++ b/packages/integrations/node/test/preview-host.test.ts
@@ -1,7 +1,7 @@
 import assert from 'node:assert/strict';
 import { describe, it } from 'node:test';
 import nodejs from '../dist/index.js';
-import { loadFixture } from './test-utils.js';
+import { loadFixture } from './test-utils.ts';
 
 describe('Astro preview host', () => {
 	it('defaults to localhost', async () => {
diff --git a/packages/integrations/node/test/redirects.test.js b/packages/integrations/node/test/redirects.test.ts
similarity index 91%
rename from packages/integrations/node/test/redirects.test.js
rename to packages/integrations/node/test/redirects.test.ts
index 0688414faa3d..b46a4f2e7da0 100644
--- a/packages/integrations/node/test/redirects.test.js
+++ b/packages/integrations/node/test/redirects.test.ts
@@ -1,12 +1,11 @@
 import assert from 'node:assert/strict';
 import { after, before, describe, it } from 'node:test';
 import nodejs from '../dist/index.js';
-import { loadFixture, waitServerListen } from './test-utils.js';
+import { type Fixture, loadFixture, waitServerListen, type AdapterServer } from './test-utils.ts';
 
 describe('Redirects', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let server;
+	let fixture: Fixture;
+	let server: AdapterServer;
 
 	before(async () => {
 		fixture = await loadFixture({
@@ -25,7 +24,7 @@ describe('Redirects', () => {
 		await fixture.clean();
 	});
 
-	function fetchEndpoint(url, options = {}) {
+	function fetchEndpoint(url: string, options: RequestInit = {}) {
 		return fetch(`http://${server.host}:${server.port}/${url}`, { ...options, redirect: 'manual' });
 	}
 
diff --git a/packages/integrations/node/test/server-host.test.js b/packages/integrations/node/test/server-host.test.ts
similarity index 100%
rename from packages/integrations/node/test/server-host.test.js
rename to packages/integrations/node/test/server-host.test.ts
diff --git a/packages/integrations/node/test/sessions.test.js b/packages/integrations/node/test/sessions.test.ts
similarity index 93%
rename from packages/integrations/node/test/sessions.test.js
rename to packages/integrations/node/test/sessions.test.ts
index 5abd5a566c5d..9cee8bae9403 100644
--- a/packages/integrations/node/test/sessions.test.js
+++ b/packages/integrations/node/test/sessions.test.ts
@@ -1,16 +1,14 @@
-// @ts-check
 import assert from 'node:assert/strict';
 import { after, before, describe, it } from 'node:test';
+import type { PreviewServer } from '../../../astro/src/types/public/preview.js';
 import * as devalue from 'devalue';
 import nodejs from '../dist/index.js';
-import { loadFixture } from './test-utils.js';
+import { type Fixture, loadFixture, type DevServer } from './test-utils.ts';
 
 describe('Astro.session', () => {
 	describe('Production', () => {
-		/** @type {import('./test-utils').Fixture} */
-		let fixture;
-		/** @type {import('../../../astro/src/types/public/preview.js').PreviewServer} */
-		let app;
+		let fixture: Fixture;
+		let app: PreviewServer;
 
 		before(async () => {
 			fixture = await loadFixture({
@@ -18,8 +16,8 @@ describe('Astro.session', () => {
 				output: 'server',
 				adapter: nodejs({ mode: 'middleware' }),
 			});
-			await fixture.build({});
-			app = await fixture.preview({});
+			await fixture.build();
+			app = await fixture.preview();
 		});
 
 		after(async () => {
@@ -95,9 +93,8 @@ describe('Astro.session', () => {
 	});
 
 	describe('Development', () => {
-		/** @type {import('./test-utils').Fixture} */
-		let fixture;
-		let devServer;
+		let fixture: Fixture;
+		let devServer: DevServer;
 		before(async () => {
 			fixture = await loadFixture({
 				root: './fixtures/sessions/',
diff --git a/packages/integrations/node/test/static-headers.test.js b/packages/integrations/node/test/static-headers.test.ts
similarity index 82%
rename from packages/integrations/node/test/static-headers.test.js
rename to packages/integrations/node/test/static-headers.test.ts
index 3dc3d98f4c37..68bfb82b089b 100644
--- a/packages/integrations/node/test/static-headers.test.js
+++ b/packages/integrations/node/test/static-headers.test.ts
@@ -1,10 +1,12 @@
 import * as assert from 'node:assert/strict';
 import { after, before, describe, it } from 'node:test';
 import nodejs from '../dist/index.js';
-import { loadFixture, waitServerListen } from './test-utils.js';
+import { type Fixture, loadFixture, waitServerListen, type AdapterServer } from './test-utils.ts';
+
+type StaticHeaderEntry = { pathname: string; headers: Array<{ key: string; value: string }> };
 
 describe('Static headers', () => {
-	let fixture;
+	let fixture: Fixture;
 
 	before(async () => {
 		fixture = await loadFixture({ root: './fixtures/static-headers' });
@@ -12,11 +14,13 @@ describe('Static headers', () => {
 	});
 
 	it('CSP headers are added when CSP is enabled', async () => {
-		const headers = JSON.parse(await fixture.readFile('../dist/_headers.json'));
+		const headers: StaticHeaderEntry[] = JSON.parse(
+			await fixture.readFile('../dist/_headers.json'),
+		);
 
 		const csp = headers
-			.find((x) => x.pathname === '/')
-			.headers.find((x) => x.key === 'Content-Security-Policy');
+			.find((x) => x.pathname === '/')!
+			.headers.find((x) => x.key === 'Content-Security-Policy')!;
 
 		assert.notEqual(csp, undefined, 'the index must have CSP headers');
 		assert.ok(
@@ -29,9 +33,8 @@ describe('Static headers', () => {
 });
 
 describe('Static headers', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let server;
+	let fixture: Fixture;
+	let server: AdapterServer;
 
 	before(async () => {
 		fixture = await loadFixture({
@@ -55,7 +58,7 @@ describe('Static headers', () => {
 
 	it('CSP headers are added to the request', async () => {
 		const res = await fetch(`http://${server.host}:${server.port}/`);
-		const cps = res.headers.get('Content-Security-Policy');
+		const cps = res.headers.get('Content-Security-Policy')!;
 		assert.ok(
 			cps.includes('script-src'),
 			'should contain script-src directive due to server island',
@@ -64,7 +67,7 @@ describe('Static headers', () => {
 
 	it('CSP headers are added to dynamic orute', async () => {
 		const res = await fetch(`http://${server.host}:${server.port}/one`);
-		const cps = res.headers.get('Content-Security-Policy');
+		const cps = res.headers.get('Content-Security-Policy')!;
 		assert.ok(
 			cps.includes('script-src'),
 			'should contain script-src directive due to server island',
@@ -73,9 +76,8 @@ describe('Static headers', () => {
 });
 
 describe('Static headers with non-root base', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let server;
+	let fixture: Fixture;
+	let server: AdapterServer;
 
 	before(async () => {
 		fixture = await loadFixture({
diff --git a/packages/integrations/node/test/test-utils.js b/packages/integrations/node/test/test-utils.js
deleted file mode 100644
index 8553a159e09c..000000000000
--- a/packages/integrations/node/test/test-utils.js
+++ /dev/null
@@ -1,82 +0,0 @@
-import { EventEmitter } from 'node:events';
-import httpMocks from 'node-mocks-http';
-import { loadFixture as baseLoadFixture } from '../../../astro/test/test-utils.js';
-
-process.env.ASTRO_NODE_AUTOSTART = 'disabled';
-process.env.ASTRO_NODE_LOGGING = 'disabled';
-/**
- * @typedef {import('../../../astro/test/test-utils').Fixture} Fixture
- */
-
-export function loadFixture(inlineConfig) {
-	if (!inlineConfig?.root) throw new Error("Must provide { root: './fixtures/...' }");
-
-	// resolve the relative root (i.e. "./fixtures/tailwindcss") to a full filepath
-	// without this, the main `loadFixture` helper will resolve relative to `packages/astro/test`
-	return baseLoadFixture({
-		...inlineConfig,
-		root: new URL(inlineConfig.root, import.meta.url).toString(),
-	});
-}
-
-export function createRequestAndResponse(reqOptions) {
-	const req = httpMocks.createRequest(reqOptions);
-
-	const res = httpMocks.createResponse({
-		eventEmitter: EventEmitter,
-		req,
-	});
-
-	const done = toPromise(res);
-
-	// Get the response as text
-	const text = async () => {
-		const chunks = await done;
-		return buffersToString(chunks);
-	};
-
-	return { req, res, done, text };
-}
-
-/** @returns {Promise<Array<Buffer>>} */
-function toPromise(res) {
-	return new Promise((resolve) => {
-		// node-mocks-http doesn't correctly handle non-Buffer typed arrays,
-		// so override the write method to fix it.
-		const write = res.write;
-		res.write = function (data, encoding) {
-			if (ArrayBuffer.isView(data) && !Buffer.isBuffer(data)) {
-				data = Buffer.from(data.buffer);
-			}
-			return write.call(this, data, encoding);
-		};
-		res.on('end', () => {
-			const chunks = res._getChunks();
-			resolve(chunks);
-		});
-	});
-}
-
-function buffersToString(buffers) {
-	const decoder = new TextDecoder();
-	let str = '';
-	for (const buffer of buffers) {
-		str += decoder.decode(buffer);
-	}
-	return str;
-}
-
-export function waitServerListen(server) {
-	return new Promise((resolve, reject) => {
-		function onListen() {
-			server.off('error', onError);
-			resolve();
-		}
-		function onError(error) {
-			server.off('listening', onListen);
-			reject(error);
-		}
-		server.once('listening', onListen);
-		server.once('error', onError);
-	});
-}
diff --git a/packages/integrations/node/test/test-utils.ts b/packages/integrations/node/test/test-utils.ts
new file mode 100644
index 000000000000..3fea903844cd
--- /dev/null
+++ b/packages/integrations/node/test/test-utils.ts
@@ -0,0 +1,94 @@
+import { EventEmitter } from 'node:events';
+import type { Server, ServerResponse } from 'node:http';
+import * as httpMocks from 'node-mocks-http';
+import {
+	type AstroInlineConfig,
+	type Fixture,
+	type AdapterServer,
+	type DevServer,
+	loadFixture as baseLoadFixture,
+} from '../../../astro/test/test-utils.js';
+import type * as express from 'express';
+
+process.env.ASTRO_NODE_AUTOSTART = 'disabled';
+process.env.ASTRO_NODE_LOGGING = 'disabled';
+
+export type { AstroInlineConfig, Fixture, AdapterServer, DevServer };
+
+export function loadFixture(inlineConfig: AstroInlineConfig) {
+	if (!inlineConfig?.root) throw new Error("Must provide { root: './fixtures/...' }");
+
+	// resolve the relative root (i.e. "./fixtures/tailwindcss") to a full filepath
+	// without this, the main `loadFixture` helper will resolve relative to `packages/astro/test`
+	return baseLoadFixture({
+		...inlineConfig,
+		root: new URL(inlineConfig.root as string, import.meta.url).toString(),
+	});
+}
+
+export function createRequestAndResponse(reqOptions?: httpMocks.RequestOptions): {
+	req: httpMocks.MockRequest<express.Request>;
+	res: httpMocks.MockResponse<ServerResponse>;
+	done: Promise<Buffer<ArrayBufferLike>[]>;
+	text: () => Promise<string>;
+} {
+	const req: httpMocks.MockRequest<express.Request> =
+		httpMocks.createRequest<express.Request>(reqOptions);
+
+	const res: httpMocks.MockResponse<ServerResponse> = httpMocks.createResponse<ServerResponse>({
+		eventEmitter: EventEmitter,
+		req,
+	});
+
+	const done: Promise<Buffer<ArrayBufferLike>[]> = toPromise(res);
+
+	// Get the response as text
+	const text: () => Promise<string> = async () => {
+		const chunks = await done;
+		return buffersToString(chunks);
+	};
+
+	return { req, res, done, text };
+}
+
+function toPromise(res: httpMocks.MockResponse<ServerResponse>): Promise<Array<Buffer>> {
+	return new Promise((resolve) => {
+		// node-mocks-http doesn't correctly handle non-Buffer typed arrays,
+		// so override the write method to fix it.
+		const write = res.write;
+		res.write = function (data: any, encoding?: any) {
+			if (ArrayBuffer.isView(data) && !Buffer.isBuffer(data)) {
+				data = Buffer.from(data.buffer);
+			}
+			return write.call(this, data, encoding);
+		};
+		res.on('end', () => {
+			const chunks = (res as any)._getChunks();
+			resolve(chunks);
+		});
+	});
+}
+
+function buffersToString(buffers: Array<Buffer>) {
+	const decoder = new TextDecoder();
+	let str = '';
+	for (const buffer of buffers) {
+		str += decoder.decode(buffer);
+	}
+	return str;
+}
+
+export function waitServerListen(server: Server): Promise<void> {
+	return new Promise((resolve, reject) => {
+		function onListen() {
+			server.off('error', onError);
+			resolve();
+		}
+		function onError(error: Error) {
+			server.off('listening', onListen);
+			reject(error);
+		}
+		server.once('listening', onListen);
+		server.once('error', onError);
+	});
+}
diff --git a/packages/integrations/node/test/trailing-slash.test.js b/packages/integrations/node/test/trailing-slash.test.ts
similarity index 98%
rename from packages/integrations/node/test/trailing-slash.test.js
rename to packages/integrations/node/test/trailing-slash.test.ts
index 8bd0be007c3e..ef375823761d 100644
--- a/packages/integrations/node/test/trailing-slash.test.js
+++ b/packages/integrations/node/test/trailing-slash.test.ts
@@ -2,16 +2,11 @@ import * as assert from 'node:assert/strict';
 import { after, before, describe, it } from 'node:test';
 import * as cheerio from 'cheerio';
 import nodejs from '../dist/index.js';
-import { loadFixture, waitServerListen } from './test-utils.js';
-
-/**
- * @typedef {import('../../../astro/test/test-utils').Fixture} Fixture
- */
+import { type Fixture, loadFixture, waitServerListen, type AdapterServer } from './test-utils.ts';
 
 describe('Trailing slash', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
-	let server;
+	let fixture: Fixture;
+	let server: AdapterServer;
 	describe('Always', async () => {
 		describe('With base', async () => {
 			before(async () => {
diff --git a/packages/integrations/node/test/url.test.js b/packages/integrations/node/test/url.test.ts
similarity index 82%
rename from packages/integrations/node/test/url.test.js
rename to packages/integrations/node/test/url.test.ts
index c3e90ead56f9..2c7b4fbac32f 100644
--- a/packages/integrations/node/test/url.test.js
+++ b/packages/integrations/node/test/url.test.ts
@@ -1,13 +1,13 @@
 import * as assert from 'node:assert/strict';
+import { Socket } from 'node:net';
 import { before, describe, it } from 'node:test';
 import { TLSSocket } from 'node:tls';
 import * as cheerio from 'cheerio';
 import nodejs from '../dist/index.js';
-import { createRequestAndResponse, loadFixture } from './test-utils.js';
+import { createRequestAndResponse, type Fixture, loadFixture } from './test-utils.ts';
 
 describe('URL', () => {
-	/** @type {import('./test-utils.js').Fixture} */
-	let fixture;
+	let fixture: Fixture;
 
 	before(async () => {
 		fixture = await loadFixture({
@@ -19,7 +19,7 @@ describe('URL', () => {
 	});
 
 	it('return http when non-secure', async () => {
-		const { handler } = await import('./fixtures/url/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 		const { req, res, text } = createRequestAndResponse({
 			url: '/',
 		});
@@ -27,26 +27,28 @@ describe('URL', () => {
 		handler(req, res);
 		req.send();
 
-		const html = await text();
+		const html: string = await text();
 		assert.equal(html.includes('http:'), true);
+		assert.equal(html.includes('https:'), false);
 	});
 
 	it('return https when secure', async () => {
-		const { handler } = await import('./fixtures/url/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 		const { req, res, text } = createRequestAndResponse({
-			socket: new TLSSocket(),
+			socket: new TLSSocket(new Socket()),
 			url: '/',
 		});
 
 		handler(req, res);
 		req.send();
 
-		const html = await text();
+		const html: string = await text();
+		assert.equal(html.includes('http:'), false);
 		assert.equal(html.includes('https:'), true);
 	});
 
 	it('return http when the X-Forwarded-Proto header is set to http', async () => {
-		const { handler } = await import('./fixtures/url/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 		const { req, res, text } = createRequestAndResponse({
 			headers: { 'X-Forwarded-Proto': 'http' },
 			url: '/',
@@ -60,7 +62,7 @@ describe('URL', () => {
 	});
 
 	it('return https when the X-Forwarded-Proto header is set to https', async () => {
-		const { handler } = await import('./fixtures/url/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 		const { req, res, text } = createRequestAndResponse({
 			headers: { 'X-Forwarded-Proto': 'https' },
 			url: '/',
@@ -74,7 +76,7 @@ describe('URL', () => {
 	});
 
 	it('includes forwarded host and port in the url', async () => {
-		const { handler } = await import('./fixtures/url/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 		const { req, res, text } = createRequestAndResponse({
 			headers: {
 				'X-Forwarded-Proto': 'https',
@@ -95,7 +97,7 @@ describe('URL', () => {
 	});
 
 	it('accepts port in forwarded host and forwarded port', async () => {
-		const { handler } = await import('./fixtures/url/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 		const { req, res, text } = createRequestAndResponse({
 			headers: {
 				'X-Forwarded-Proto': 'https',
@@ -115,7 +117,7 @@ describe('URL', () => {
 	});
 
 	it('ignores X-Forwarded-Host when no allowedDomains configured', async () => {
-		const { handler } = await import('./fixtures/url/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 		const { req, res, text } = createRequestAndResponse({
 			headers: {
 				'X-Forwarded-Proto': 'https',
@@ -136,7 +138,7 @@ describe('URL', () => {
 	});
 
 	it('rejects port in forwarded host when port not in allowedDomains', async () => {
-		const { handler } = await import('./fixtures/url/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 		const { req, res, text } = createRequestAndResponse({
 			headers: {
 				'X-Forwarded-Proto': 'https',
@@ -157,7 +159,7 @@ describe('URL', () => {
 	});
 
 	it('rejects empty X-Forwarded-Host with allowedDomains configured', async () => {
-		const { handler } = await import('./fixtures/url/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 		const { req, res, text } = createRequestAndResponse({
 			headers: {
 				'X-Forwarded-Proto': 'https',
@@ -178,7 +180,7 @@ describe('URL', () => {
 	});
 
 	it('rejects X-Forwarded-Host with path injection attempt', async () => {
-		const { handler } = await import('./fixtures/url/dist/server/entry.mjs');
+		const handler = await fixture.loadNodeAdapterHandler();
 		const { req, res, text } = createRequestAndResponse({
 			headers: {
 				'X-Forwarded-Proto': 'https',
diff --git a/packages/integrations/node/test/well-known-locations.test.js b/packages/integrations/node/test/well-known-locations.test.ts
similarity index 84%
rename from packages/integrations/node/test/well-known-locations.test.js
rename to packages/integrations/node/test/well-known-locations.test.ts
index 57082f28ad6e..a8afdd1519b4 100644
--- a/packages/integrations/node/test/well-known-locations.test.js
+++ b/packages/integrations/node/test/well-known-locations.test.ts
@@ -1,11 +1,11 @@
 import * as assert from 'node:assert/strict';
 import { after, before, describe, it } from 'node:test';
+import type { PreviewServer } from '../../../astro/src/types/public/preview.js';
 import nodejs from '../dist/index.js';
-import { createRequestAndResponse, loadFixture } from './test-utils.js';
+import { createRequestAndResponse, type Fixture, loadFixture } from './test-utils.ts';
 
 describe('test URIs beginning with a dot', () => {
-	/** @type {import('./test-utils').Fixture} */
-	let fixture;
+	let fixture: Fixture;
 
 	before(async () => {
 		fixture = await loadFixture({
@@ -17,7 +17,7 @@ describe('test URIs beginning with a dot', () => {
 	});
 
 	describe('can load well-known URIs', async () => {
-		let devPreview;
+		let devPreview: PreviewServer;
 
 		before(async () => {
 			devPreview = await fixture.preview();
@@ -46,7 +46,7 @@ describe('test URIs beginning with a dot', () => {
 
 	describe('dotfile access via unnormalized paths', async () => {
 		it('denies dotfile access when path contains .well-known/../ traversal', async () => {
-			const { handler } = await import('./fixtures/well-known-locations/dist/server/entry.mjs');
+			const handler = await fixture.loadNodeAdapterHandler();
 			const { req, res, done } = createRequestAndResponse({
 				method: 'GET',
 				url: '/.well-known/../.hidden-file',
@@ -64,7 +64,7 @@ describe('test URIs beginning with a dot', () => {
 		});
 
 		it('denies dotfolder file access when path contains .well-known/../ traversal', async () => {
-			const { handler } = await import('./fixtures/well-known-locations/dist/server/entry.mjs');
+			const handler = await fixture.loadNodeAdapterHandler();
 			const { req, res, done } = createRequestAndResponse({
 				method: 'GET',
 				url: '/.well-known/../.hidden/file.json',
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index e7deedf8b21b..b1dbd3ac3ad9 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -729,7 +729,7 @@ importers:
         version: 3.2.0
       node-mocks-http:
         specifier: ^1.17.2
-        version: 1.17.2(@types/node@25.2.3)
+        version: 1.17.2(@types/express@5.0.6)(@types/node@25.2.3)
       parse-srcset:
         specifier: ^1.0.2
         version: 1.0.2
@@ -5651,6 +5651,9 @@ importers:
       '@fastify/static':
         specifier: ^9.0.0
         version: 9.0.0
+      '@types/express':
+        specifier: ^5.0.6
+        version: 5.0.6
       '@types/node':
         specifier: ^22.10.6
         version: 22.19.11
@@ -5680,7 +5683,7 @@ importers:
         version: 5.8.3
       node-mocks-http:
         specifier: ^1.17.2
-        version: 1.17.2(@types/node@22.19.11)
+        version: 1.17.2(@types/express@5.0.6)(@types/node@22.19.11)
 
   packages/integrations/node/test/fixtures/api-route:
     dependencies:
@@ -9875,12 +9878,18 @@ packages:
   '@types/babel__traverse@7.28.0':
     resolution: {integrity: sha512-8PvcXf70gTDZBgt9ptxJ8elBeBjcLOAcOtoO/mPJjtji1+CdGbHgm77om1GrsPxsiE+uXIpNSK64UYaIwQXd4Q==}
 
+  '@types/body-parser@1.19.6':
+    resolution: {integrity: sha512-HLFeCYgz89uk22N5Qg3dvGvsv46B8GLvKKo1zKG4NybA8U2DiEO3w9lqGg29t/tfLRJpJ6iQxnVw4OnB7MoM9g==}
+
   '@types/canvas-confetti@1.9.0':
     resolution: {integrity: sha512-aBGj/dULrimR1XDZLtG9JwxX1b4HPRF6CX9Yfwh3NvstZEm1ZL7RBnel4keCPSqs1ANRu1u2Aoz9R+VmtjYuTg==}
 
   '@types/chai@5.2.3':
     resolution: {integrity: sha512-Mw558oeA9fFbv65/y4mHtXDs9bPnFMZAL/jxdPFUpOHHIXX91mcgEHbS5Lahr+pwZFR8A7GQleRWeI6cGFC2UA==}
 
+  '@types/connect@3.4.38':
+    resolution: {integrity: sha512-K6uROf1LD88uDQqJCktA4yzL1YYAK6NgfsI0v/mTgyPKWsX1CnJ0XPSDhViejru1GcRkLWb8RlzFYJRqGUbaug==}
+
   '@types/debug@4.1.12':
     resolution: {integrity: sha512-vIChWdVG3LG1SMxEvI/AK+FWJthlrqlTu7fbrlywTkkaONwk/UAGaULXRlf8vkzFBLVm0zkMdCquhL5aOjhXPQ==}
 
@@ -9896,6 +9905,12 @@ packages:
   '@types/estree@1.0.8':
     resolution: {integrity: sha512-dWHzHa2WqEXI/O1E9OjrocMTKJl2mSrEolh1Iomrv6U+JuNwaHXsXx9bLu5gG7BUWFIN0skIQJQ/L1rIex4X6w==}
 
+  '@types/express-serve-static-core@5.1.1':
+    resolution: {integrity: sha512-v4zIMr/cX7/d2BpAEX3KNKL/JrT1s43s96lLvvdTmza1oEvDudCqK9aF/djc/SWgy8Yh0h30TZx5VpzqFCxk5A==}
+
+  '@types/express@5.0.6':
+    resolution: {integrity: sha512-sKYVuV7Sv9fbPIt/442koC7+IIwK5olP1KWeD88e/idgoJqDm3JV/YUiPwkoKK92ylff2MGxSz1CSjsXelx0YA==}
+
   '@types/hast@3.0.4':
     resolution: {integrity: sha512-WPs+bbQw5aCj+x6laNGWLH3wviHtoCv/P3+otBhbOhJgG8qtpdAMlTCxLtsTWA7LH1Oh/bFCHsBn0TPS5m30EQ==}
 
@@ -9905,6 +9920,9 @@ packages:
   '@types/http-cache-semantics@4.2.0':
     resolution: {integrity: sha512-L3LgimLHXtGkWikKnsPg0/VFx9OGZaC+eN1u4r+OB1XRqH3meBIAVC2zr1WdMH+RHmnRkqliQAOHNJ/E0j/e0Q==}
 
+  '@types/http-errors@2.0.5':
+    resolution: {integrity: sha512-r8Tayk8HJnX0FztbZN7oVqGccWgw98T/0neJphO91KkmOzug1KkofZURD4UaD5uH8AqcFLfdPErnBod0u71/qg==}
+
   '@types/istanbul-lib-coverage@2.0.6':
     resolution: {integrity: sha512-2QF/t/auWm0lsy8XtKVPG19v3sSOQlJe/YHZgfjb/KBBHOGSV+J2q/S671rcq9uTBrLAXmZpqJiaQbMT+zNU1w==}
 
@@ -9977,6 +9995,12 @@ packages:
   '@types/prop-types@15.7.15':
     resolution: {integrity: sha512-F6bEyamV9jKGAFBEmlQnesRPGOQqS2+Uwi0Em15xenOxHaf2hv6L8YCVn3rPdPJOiJfPiCnLIRyvwVaqMY3MIw==}
 
+  '@types/qs@6.15.0':
+    resolution: {integrity: sha512-JawvT8iBVWpzTrz3EGw9BTQFg3BQNmwERdKE22vlTxawwtbyUSlMppvZYKLZzB5zgACXdXxbD3m1bXaMqP/9ow==}
+
+  '@types/range-parser@1.2.7':
+    resolution: {integrity: sha512-hKormJbkJqzQGhziax5PItDUTMAM9uE2XXQmM37dyd4hVM+5aVl7oVxMVUiVQn2oCQFN/LKCZdvSM0pFRqbSmQ==}
+
   '@types/react-dom@18.3.7':
     resolution: {integrity: sha512-MEe3UeoENYVFXzoXEWsvcpg6ZvlrFNlOQ7EOsvhI3CfAXwzPfO8Qwuxd40nepsYKqyyVQnTdEfv68q91yLcKrQ==}
     peerDependencies:
@@ -10000,6 +10024,9 @@ packages:
   '@types/send@1.2.1':
     resolution: {integrity: sha512-arsCikDvlU99zl1g69TcAB3mzZPpxgw0UQnaHeC1Nwb015xp8bknZv5rIfri9xTOcMuaVgvabfIRA7PSZVuZIQ==}
 
+  '@types/serve-static@2.2.0':
+    resolution: {integrity: sha512-8mam4H1NHLtu7nmtalF7eyBH14QyOASmcxHhSfEoRyr0nP/YdoesEtU+uSRvMe96TW/HPTtkoKqQLl53N7UXMQ==}
+
   '@types/server-destroy@1.0.4':
     resolution: {integrity: sha512-+x8oAQ4Xp1wtDi2Hlmi7gUNXZNVhB5EoSQpi0qEmINdDN5Ab724WLGAalEdT1SudVY/NzMhbfZO7vU+klT0R+A==}
 
@@ -18784,6 +18811,11 @@ snapshots:
     dependencies:
       '@babel/types': 7.29.0
 
+  '@types/body-parser@1.19.6':
+    dependencies:
+      '@types/connect': 3.4.38
+      '@types/node': 25.2.3
+
   '@types/canvas-confetti@1.9.0': {}
 
   '@types/chai@5.2.3':
@@ -18791,6 +18823,10 @@ snapshots:
       '@types/deep-eql': 4.0.2
       assertion-error: 2.0.1
 
+  '@types/connect@3.4.38':
+    dependencies:
+      '@types/node': 25.2.3
+
   '@types/debug@4.1.12':
     dependencies:
       '@types/ms': 2.1.0
@@ -18805,6 +18841,19 @@ snapshots:
 
   '@types/estree@1.0.8': {}
 
+  '@types/express-serve-static-core@5.1.1':
+    dependencies:
+      '@types/node': 25.2.3
+      '@types/qs': 6.15.0
+      '@types/range-parser': 1.2.7
+      '@types/send': 1.2.1
+
+  '@types/express@5.0.6':
+    dependencies:
+      '@types/body-parser': 1.19.6
+      '@types/express-serve-static-core': 5.1.1
+      '@types/serve-static': 2.2.0
+
   '@types/hast@3.0.4':
     dependencies:
       '@types/unist': 3.0.3
@@ -18813,6 +18862,8 @@ snapshots:
 
   '@types/http-cache-semantics@4.2.0': {}
 
+  '@types/http-errors@2.0.5': {}
+
   '@types/istanbul-lib-coverage@2.0.6': {}
 
   '@types/js-yaml@4.0.9': {}
@@ -18881,6 +18932,10 @@ snapshots:
 
   '@types/prop-types@15.7.15': {}
 
+  '@types/qs@6.15.0': {}
+
+  '@types/range-parser@1.2.7': {}
+
   '@types/react-dom@18.3.7(@types/react@18.3.28)':
     dependencies:
       '@types/react': 18.3.28
@@ -18904,6 +18959,11 @@ snapshots:
     dependencies:
       '@types/node': 25.2.3
 
+  '@types/serve-static@2.2.0':
+    dependencies:
+      '@types/http-errors': 2.0.5
+      '@types/node': 25.2.3
+
   '@types/server-destroy@1.0.4':
     dependencies:
       '@types/node': 25.2.3
@@ -22945,7 +23005,7 @@ snapshots:
 
   node-mock-http@1.0.4: {}
 
-  node-mocks-http@1.17.2(@types/node@22.19.11):
+  node-mocks-http@1.17.2(@types/express@5.0.6)(@types/node@22.19.11):
     dependencies:
       accepts: 1.3.8
       content-disposition: 0.5.4
@@ -22958,9 +23018,10 @@ snapshots:
       range-parser: 1.2.1
       type-is: 1.6.18
     optionalDependencies:
+      '@types/express': 5.0.6
       '@types/node': 22.19.11
 
-  node-mocks-http@1.17.2(@types/node@25.2.3):
+  node-mocks-http@1.17.2(@types/express@5.0.6)(@types/node@25.2.3):
     dependencies:
       accepts: 1.3.8
       content-disposition: 0.5.4
@@ -22973,6 +23034,7 @@ snapshots:
       range-parser: 1.2.1
       type-is: 1.6.18
     optionalDependencies:
+      '@types/express': 5.0.6
       '@types/node': 25.2.3
 
   node-releases@2.0.27: {}