test(api): use random ports for getFreePort e2e tests

tests/e2e/api.test.js

@@ -4,6 +4,7 @@ const { RspackDevServer: Server } = require('@rspack/dev-server');
 const config = require('../fixtures/client-config/rspack.config');
 const runBrowser = require('../helpers/run-browser');
 const sessionSubscribe = require('../helpers/session-subscribe');
+const { getRandomPorts } = require('../helpers/get-random-port');
 const port = require('../helpers/ports-map').api;
 
 describe('API', () => {
@@ -337,12 +338,19 @@ describe('API', () => {
   });
 
   describe('Server.getFreePort', () => {
+    let basePort;
+    let reservedPorts;
     let dummyServers = [];
     let devServerPort;
 
+    beforeEach(async () => {
+      reservedPorts = await getRandomPorts(8, '0.0.0.0');
+      [basePort] = reservedPorts;
+    });
+
     afterEach(() => {
-      process.env.RSPACK_DEV_SERVER_BASE_PORT = undefined;
-      process.env.RSPACK_DEV_SERVER_PORT_RETRY = undefined;
+      delete process.env.RSPACK_DEV_SERVER_BASE_PORT;
+      delete process.env.RSPACK_DEV_SERVER_PORT_RETRY;
 
       return dummyServers
         .reduce(
@@ -363,14 +371,14 @@ describe('API', () => {
     });
 
     function createDummyServers(n) {
-      process.env.RSPACK_DEV_SERVER_BASE_PORT = 60000;
+      process.env.RSPACK_DEV_SERVER_BASE_PORT = `${basePort}`;
 
       return (Array.isArray(n) ? n : [...new Array(n)]).reduce(
         (p, _, i) =>
           p.then(
             () =>
               new Promise((resolve) => {
-                devServerPort = 60000 + i;
+                devServerPort = basePort + i;
                 const compiler = rspack(config);
                 const server = new Server(
                   { port: devServerPort, host: '0.0.0.0' },
@@ -407,7 +415,7 @@ describe('API', () => {
 
       const freePort = await Server.getFreePort(null);
 
-      expect(freePort).toEqual(60000 + retryCount);
+      expect(freePort).toEqual(basePort + retryCount);
 
       const { page, browser } = await runBrowser();
 
@@ -447,7 +455,7 @@ describe('API', () => {
       // eslint-disable-next-line no-undefined
       const freePort = await Server.getFreePort(undefined);
 
-      expect(freePort).toEqual(60000 + retryCount);
+      expect(freePort).toEqual(basePort + retryCount);
 
       const { page, browser } = await runBrowser();
 
@@ -486,7 +494,7 @@ describe('API', () => {
 
       const freePort = await Server.getFreePort();
 
-      expect(freePort).toEqual(60000 + retryCount);
+      expect(freePort).toEqual(basePort + retryCount);
 
       const { page, browser } = await runBrowser();
 
@@ -525,7 +533,7 @@ describe('API', () => {
 
       const freePort = await Server.getFreePort();
 
-      expect(freePort).toEqual(60000 + retryCount);
+      expect(freePort).toEqual(basePort + retryCount);
 
       const { page, browser } = await runBrowser();
 
@@ -556,15 +564,15 @@ describe('API', () => {
     });
 
     it('should retry finding the port when serial ports are busy', async () => {
-      const busyPorts = [60000, 60001, 60002, 60003, 60004, 60005];
+      const busyPorts = reservedPorts.slice(0, 6);
 
       process.env.RSPACK_DEV_SERVER_PORT_RETRY = 1000;
 
       await createDummyServers(busyPorts);
 
       const freePort = await Server.getFreePort();
 
-      expect(freePort).toBeGreaterThan(60005);
+      expect(freePort).toBeGreaterThan(busyPorts[busyPorts.length - 1]);
 
       const { page, browser } = await runBrowser();
 

tests/helpers/get-random-port.js

@@ -0,0 +1,87 @@
+const net = require('node:net');
+
+function isPortAvailable(port, host = '0.0.0.0') {
+  try {
+    const server = net.createServer();
+
+    server.unref();
+
+    return new Promise((resolve) => {
+      server.on('listening', () => {
+        server.close(() => {
+          resolve(true);
+        });
+      });
+      server.on('error', () => {
+        resolve(false);
+      });
+      server.listen(port, host);
+    });
+  } catch {
+    return false;
+  }
+}
+
+const portMap = new Map();
+
+/**
+ * Get a random port.
+ * Available port ranges: 1024 ~ 65535
+ * `10080` is not available on macOS CI, `> 50000` gets "permission denied" on Windows,
+ * so we use `15000` ~ `45000`.
+ */
+async function getRandomPort(
+  defaultPort = Math.ceil(Math.random() * 30000) + 15000,
+  host,
+) {
+  let port = defaultPort;
+
+  while (true) {
+    if (!portMap.get(port) && (await isPortAvailable(port, host))) {
+      portMap.set(port, 1);
+
+      return port;
+    }
+
+    port += 1;
+  }
+}
+
+async function getRandomPorts(count, host) {
+  let port = await getRandomPort(undefined, host);
+
+  while (true) {
+    let isAvailable = true;
+
+    for (let index = 0; index < count; index += 1) {
+      const currentPort = port + index;
+
+      if (
+        portMap.get(currentPort) ||
+        !(await isPortAvailable(currentPort, host))
+      ) {
+        isAvailable = false;
+        port = currentPort + 1;
+        break;
+      }
+    }
+
+    if (isAvailable) {
+      const ports = [];
+
+      for (let index = 0; index < count; index += 1) {
+        const currentPort = port + index;
+
+        portMap.set(currentPort, 1);
+        ports.push(currentPort);
+      }
+
+      return ports;
+    }
+  }
+}
+
+module.exports = {
+  getRandomPort,
+  getRandomPorts,
+};