Use a dynamic port for the test-http-api to avoid conflicts

Pick a free port at config load time using a TCP probe on port 0, inject
it into the Vite dev server via VITE_TEST_HTTP_API_PORT, and have
globalSetup start the test-http-api on the same port. The frontend
reads the env var at build time instead of the previously hardcoded 8081.

playwright.config.ts

@@ -1,7 +1,23 @@
 import type { PlaywrightTestConfig } from "@playwright/test";
 
+import * as net from "node:net";
+
 import { devices } from "@playwright/test";
 
+function getFreePort(): Promise<number> {
+  return new Promise((resolve, reject) => {
+    const server = net.createServer();
+    server.listen(0, "127.0.0.1", () => {
+      const port = (server.address() as net.AddressInfo).port;
+      server.close(err => (err ? reject(err) : resolve(port)));
+    });
+    server.on("error", reject);
+  });
+}
+
+const testHttpApiPort = await getFreePort();
+process.env.VITE_TEST_HTTP_API_PORT = String(testHttpApiPort);
+
 const config: PlaywrightTestConfig = {
   outputDir: "./tests/artifacts",
   testDir: "./tests/e2e",
@@ -33,8 +49,7 @@ const config: PlaywrightTestConfig = {
 
   webServer: [
     {
-      command:
-        "VITE_AUTH_LONG_DELAY=1000 npm run start -- --strictPort --port 3001",
+      command: `VITE_AUTH_LONG_DELAY=1000 VITE_TEST_HTTP_API_PORT=${testHttpApiPort} npm run start -- --strictPort --port 3001`,
       port: 3001,
     },
   ],

src/lib/invoke.ts

@@ -49,11 +49,14 @@ async function withTestBackend<T>(
       }
     });
   } else {
-    return fetch(`http://127.0.0.1:8081/${cmd}`, {
-      method: "POST",
-      headers: { "Content-Type": "application/json" },
-      body: JSON.stringify(args),
-    }).then(async response => {
+    return fetch(
+      `http://127.0.0.1:${import.meta.env.VITE_TEST_HTTP_API_PORT ?? 8081}/${cmd}`,
+      {
+        method: "POST",
+        headers: { "Content-Type": "application/json" },
+        body: JSON.stringify(args),
+      },
+    ).then(async response => {
       if (response.status === 404) {
         console.log("Got a 404 response:", response);
         return null;

tests/support/fixtures.ts

@@ -503,7 +503,6 @@ export const shortBobHead = formatOid(bobHead);
 export const cobRid = "rad:z3fpY7nttPPa6MBnAv2DccHzQJnqe";
 export const markdownRid = "rad:z2tchH2Ti4LxRKdssPQYs6VHE5rsg";
 export const shortNodeRemote = "z6MktU…1xB22S";
-export const defaultHttpdPort = 8081;
 export const gitOptions = {
   alice: {
     GIT_AUTHOR_NAME: "Alice Liddell",

tests/support/globalSetup.ts

@@ -5,7 +5,6 @@ import {
   createCobsFixture,
   createMarkdownFixture,
   defaultConfig,
-  defaultHttpdPort,
   gitOptions,
 } from "@tests/support/fixtures.js";
 import { createPeerManager } from "@tests/support/peerManager.js";
@@ -68,7 +67,7 @@ export default async function globalSetup(): Promise<() => void> {
         alias: "palm",
       },
     });
-    await palm.startHttpd(defaultHttpdPort);
+    await palm.startHttpd(parseInt(process.env.VITE_TEST_HTTP_API_PORT ?? "0"));
 
     try {
       console.log("Creating markdown fixture");
@@ -87,7 +86,7 @@ export default async function globalSetup(): Promise<() => void> {
     }
     await palm.stopNode();
   } else {
-    await palm.startHttpd(defaultHttpdPort);
+    await palm.startHttpd(parseInt(process.env.VITE_TEST_HTTP_API_PORT ?? "0"));
   }
 
   return async () => {