fixup! fixup! fixup! chore(test): improve log output on error

lib/internal/inspector-client.js

@@ -1,5 +1,6 @@
 'use strict'
 
+const net = require('net');
 const http = require('http');
 const { EventEmitter } = require('events');
 
@@ -20,6 +21,35 @@ function getWebSocketPath(host, port) {
   });
 }
 
+function timeout(time) {
+  return new Promise((resolve) => {
+    setTimeout(resolve, time);
+  });
+}
+
+function waitForConnection (host, port) {
+  return new Promise((resolve, reject) => {
+    const socket = net.createConnection({ host, port }, () => { socket.close(); resolve() });
+    socket.on('error', reject);
+  });
+}
+
+async function isInspectorOpen(host, port) {
+  // make number of retries configurable?
+  let retries = 5;
+  let portOpen = false;
+  do {
+    try {
+      await waitForConnection(host, port);
+      portOpen = true;
+    } catch {
+      // make timeout between attempts configurable?
+      await timeout(75);
+    }
+  } while (!portOpen && retries-- > 0);
+  return portOpen;
+}
+
 function handleMessages(data) {
   const { id, method, result, params} = JSON.parse(data);
   if (id) {
@@ -44,6 +74,7 @@ class Client extends EventEmitter {
 
   async connect() {
     const url = await getWebSocketPath(this.host, this.port);
+    await isInspectorOpen();
     this._ws = new WebSocket(url);
     this._ws.on('message', handleMessages.bind(this));
     return new Promise((resolve) => {