Add basic smoke tests for adapter-node

* verify the server starts
* verify it can serve a 404

---

Additional changes:

- change server.js to be a function that creates the server but does not start it.
- update build rules to build from a new index.js file that builds and
starts the app
- update the package type to module to enable esm imports
- expose a way to call into server with a render function
- add a guard clause around no static asset folder existing.
- change imports in adapter-node to work with import and not require

BUG sveltejs#639

packages/adapter-node/index.js

@@ -1,5 +1,5 @@
-const { copyFileSync } = require('fs');
-const { join } = require('path');
+import { copyFileSync } from 'fs';
+import { join } from 'path';
 
 /**
  * @param {{

packages/adapter-node/package.json

@@ -2,12 +2,14 @@
 	"name": "@sveltejs/adapter-node",
 	"version": "1.0.0-next.11",
 	"main": "index.js",
+	"type": "module",
 	"files": [
 		"files"
 	],
 	"scripts": {
 		"dev": "rollup -cw",
 		"build": "rollup -c",
+		"test": "uvu tests",
 		"lint": "eslint --ignore-path .gitignore \"**/*.{ts,js,svelte}\" && npm run check-format",
 		"format": "prettier --write . --config ../../.prettierrc --ignore-path .gitignore",
 		"check-format": "prettier --check . --config ../../.prettierrc --ignore-path .gitignore",
@@ -17,9 +19,11 @@
 		"@rollup/plugin-json": "^4.1.0",
 		"@sveltejs/kit": "workspace:*",
 		"compression": "^1.7.4",
+		"node-fetch": "^2.6.1",
 		"polka": "^1.0.0-next.13",
 		"rollup": "^2.41.1",
 		"sirv": "^1.0.11",
-		"typescript": "^4.2.3"
+		"typescript": "^4.2.3",
+		"uvu": "^0.5.1"
 	}
 }

packages/adapter-node/rollup.config.js

@@ -3,7 +3,7 @@ import commonjs from '@rollup/plugin-commonjs';
 import json from '@rollup/plugin-json';
 
 export default {
-	input: 'src/server.js',
+	input: 'src/index.js',
 	output: {
 		file: 'files/server.js',
 		format: 'esm',

packages/adapter-node/src/index.js

@@ -0,0 +1,15 @@
+import { createServer } from './server';
+/*eslint import/no-unresolved: [2, { ignore: ['\.\/app\.js$'] }]*/
+import * as app from './app.js';
+
+const { PORT = 3000 } = process.env; // TODO configure via svelte.config.js
+
+const instance = createServer({ render: app.render }).listen(PORT, (err) => {
+	if (err) {
+		console.log('error', err);
+	} else {
+		console.log(`Listening on port ${PORT}`);
+	}
+});
+
+export { instance };

packages/adapter-node/src/server.js

@@ -7,51 +7,55 @@ import { URL, fileURLToPath } from 'url';
 // eslint-disable-next-line import/no-unresolved
 import { get_body } from '@sveltejs/kit/http';
 // App is a dynamic file built from the application layer.
-/*eslint import/no-unresolved: [2, { ignore: ['\.\/app\.js$'] }]*/
-import * as app from './app.js';
 
 const __dirname = dirname(fileURLToPath(import.meta.url));
-
-const { PORT = 3000 } = process.env; // TODO configure via svelte.config.js
-
-const mutable = (dir) =>
-	sirv(dir, {
-		etag: true,
-		maxAge: 0
-	});
-
 const noop_handler = (_req, _res, next) => next();
-
-const prerendered_handler = fs.existsSync('prerendered') ? mutable('prerendered') : noop_handler;
-
-const assets_handler = sirv(join(__dirname, '/assets'), {
-	maxAge: 31536000,
-	immutable: true
-});
-
-polka()
-	.use(compression({ threshold: 0 }), assets_handler, prerendered_handler, async (req, res) => {
-		const parsed = new URL(req.url || '', 'http://localhost');
-		const rendered = await app.render({
-			method: req.method,
-			headers: req.headers, // TODO: what about repeated headers, i.e. string[]
-			path: parsed.pathname,
-			body: await get_body(req),
-			query: parsed.searchParams
+const paths = {
+	assets: join(__dirname, '/assets'),
+	prerendered: join(__dirname, '/prerendered')
+};
+
+export function createServer({ render }) {
+	const mutable = (dir) =>
+		sirv(dir, {
+			etag: true,
+			maxAge: 0
 		});
 
-		if (rendered) {
-			res.writeHead(rendered.status, rendered.headers);
-			res.end(rendered.body);
-		} else {
-			res.statusCode = 404;
-			res.end('Not found');
+	const prerendered_handler = fs.existsSync(paths.prerendered)
+		? mutable(paths.prerendered)
+		: noop_handler;
+
+	const assets_handler = fs.existsSync(paths.assets)
+		? sirv(paths.assets, {
+				maxAge: 31536000,
+				immutable: true
+		  })
+		: noop_handler;
+
+	const server = polka().use(
+		compression({ threshold: 0 }),
+		assets_handler,
+		prerendered_handler,
+		async (req, res) => {
+			const parsed = new URL(req.url || '', 'http://localhost');
+			const rendered = await render({
+				method: req.method,
+				headers: req.headers, // TODO: what about repeated headers, i.e. string[]
+				path: parsed.pathname,
+				body: await get_body(req),
+				query: parsed.searchParams
+			});
+
+			if (rendered) {
+				res.writeHead(rendered.status, rendered.headers);
+				res.end(rendered.body);
+			} else {
+				res.statusCode = 404;
+				res.end('Not found');
+			}
 		}
-	})
-	.listen(PORT, (err) => {
-		if (err) {
-			console.log('error', err);
-		} else {
-			console.log(`Listening on port ${PORT}`);
-		}
-	});
+	);
+
+	return server;
+}

packages/adapter-node/tests/smoke.js

@@ -0,0 +1,33 @@
+import { test } from 'uvu';
+import { createServer } from '../src/server.js';
+import * as assert from 'uvu/assert';
+import fetch from 'node-fetch';
+
+const { PORT = 3000 } = process.env;
+
+function startServer() {
+	const server = createServer({ render: () => {} });
+	return new Promise((fulfil, reject) => {
+		server.listen(PORT, (err) => {
+			if (err) {
+				reject(err);
+			}
+			fulfil(server);
+		});
+	});
+}
+
+test('starts a server', async () => {
+	const server = await startServer();
+	assert.ok('server started');
+	server.server.close();
+});
+
+test('serves a 404', async () => {
+	const server = await startServer();
+	const res = await fetch(`http://localhost:${PORT}/nothing`);
+	assert.equal(res.status, 404);
+	server.server.close();
+});
+
+test.run();