Add test for http2 support

src/__tests__/http2.test.ts

@@ -0,0 +1,83 @@
+import Koa from 'koa';
+import http2 from 'http2';
+import { ApolloServer } from '@apollo/server';
+import { ApolloServerPluginDrainHttpServer } from '@apollo/server/plugin/drainHttpServer';
+import cors from '@koa/cors';
+import bodyParser from 'koa-bodyparser';
+import { koaMiddleware } from '..';
+import { urlForHttpServer } from '../utils';
+
+describe('http2', () => {
+  it('works', async () => {
+    const app = new Koa();
+    // disable logs to console.error
+    app.silent = true;
+
+    // For browser-based implementations, you need to provide a key and cert and
+    // use http2.createSecureServer. This is because browsers will only use
+    // http2 with SSL.
+    const http2Server = http2.createServer(app.callback());
+    const server = new ApolloServer({
+      typeDefs: `#graphql
+        type Query {
+          hello: String!
+        }  
+      `,
+      resolvers: {
+        Query: {
+          hello: () => 'hello world!',
+        },
+      },
+      plugins: [
+        ApolloServerPluginDrainHttpServer({
+          // @ts-expect-error drain server plugin currently only accepts an http.Server
+          httpServer: http2Server,
+        }),
+      ],
+    });
+
+    await server.start();
+    app.use(cors());
+    app.use(bodyParser());
+    app.use(koaMiddleware(server));
+    await new Promise<void>((resolve) => {
+      http2Server.listen({ port: 0 }, resolve);
+    });
+    const url = urlForHttpServer(http2Server);
+
+    const client = http2.connect(url);
+    client.on('error', (err) => console.error(err));
+
+    const body = JSON.stringify({ query: '{hello}' });
+    const contentLength = Buffer.byteLength(body);
+    const req = client.request({
+      ':method': 'POST',
+      ':path': '/',
+      'content-type': 'application/json',
+      'content-length': contentLength,
+    });
+    req.write(body);
+
+    req.setEncoding('utf8');
+    let data = '';
+    req.on('data', (chunk) => {
+      data += chunk;
+    });
+
+    let r: () => void;
+    const p = new Promise<void>((resolve) => (r = resolve));
+    req.on('end', () => {
+      client.close(r);
+    });
+
+    req.end();
+    await p;
+    expect(data).toMatchInlineSnapshot(`
+      "{"data":{"hello":"hello world!"}}
+      "
+    `);
+
+    client.destroy();
+    await server.stop();
+  });
+});

src/utils.ts

@@ -1,8 +1,10 @@
 import type { Server } from 'http';
+import type { Http2Server } from 'http2';
+
 import type { AddressInfo } from 'net';
 import { format } from 'url';
 
-export function urlForHttpServer(httpServer: Server): string {
+export function urlForHttpServer(httpServer: Server | Http2Server): string {
   const { address, port } = httpServer.address() as AddressInfo;
 
   // Convert IPs which mean "any address" (IPv4 or IPv6) into localhost