fix node 18 ipv6 address

Node 18.x seems to default to an IPv6 localhost address by default now.

Force hostname default to `localhost`.

dev-packages/cli/src/run-test.ts

@@ -63,5 +63,10 @@ export default async function runTest(options: TestOptions): Promise<void> {
     });
 
     const server = await start();
-    await testPage.goto(`http://${server.address}:${server.port}`);
+    if (net.isIPv6(server.address)) {
+        // IPv6 addresses must be put in brackets for URLs to work:
+        await testPage.goto(`http://[${server.address}]:${server.port}`);
+    } else {
+        await testPage.goto(`http://${server.address}:${server.port}`);
+    }
 }

packages/core/src/node/backend-application.ts

@@ -232,8 +232,8 @@ export class BackendApplication {
     }
 
     async start(aPort?: number, aHostname?: string): Promise<http.Server | https.Server> {
-        const hostname = aHostname !== undefined ? aHostname : this.cliParams.hostname;
-        const port = aPort !== undefined ? aPort : this.cliParams.port;
+        const hostname: string = aHostname ?? this.cliParams.hostname ?? 'localhost';
+        const port: number = aPort ?? this.cliParams.port ?? 3000;
 
         const deferred = new Deferred<http.Server | https.Server>();
         let server: http.Server | https.Server;
@@ -277,7 +277,7 @@ export class BackendApplication {
 
         server.listen(port, hostname, () => {
             const scheme = this.cliParams.ssl ? 'https' : 'http';
-            console.info(`Theia app listening on ${scheme}://${hostname || 'localhost'}:${(server.address() as AddressInfo).port}.`);
+            console.info(`Theia app listening on ${scheme}://${hostname}:${(server.address() as AddressInfo).port}.`);
             deferred.resolve(server);
         });