fix(connect): provide an error message when ws endpoint is incorrect (#4978)

src/browserServerImpl.ts

@@ -76,17 +76,13 @@ export class BrowserServerImpl extends EventEmitter implements BrowserServer {
     this._ready = new Promise<void>(f => readyCallback = f);
 
     const token = createGuid();
-    this._server = new ws.Server({ port }, () => {
+    this._server = new ws.Server({ port, path: '/' + token }, () => {
       const address = this._server.address();
       this._wsEndpoint = typeof address === 'string' ? `${address}/${token}` : `ws://127.0.0.1:${address.port}/${token}`;
       readyCallback();
     });
 
     this._server.on('connection', (socket: ws, req) => {
-      if (req.url !== '/' + token) {
-        socket.close();
-        return;
-      }
       this._clientAttached(socket);
     });
 

src/client/browserType.ts

@@ -147,6 +147,10 @@ export class BrowserType extends ChannelOwner<channels.BrowserTypeChannel, chann
           }
         }
         ws.addEventListener('open', async () => {
+          const prematureCloseListener = (event: { reason: string }) => {
+            reject(new Error('Server disconnected: ' + event.reason));
+          };
+          ws.addEventListener('close', prematureCloseListener);
           const remoteBrowser = await connection.waitForObjectWithKnownName('remoteBrowser') as RemoteBrowser;
 
           // Inherit shared selectors for connected browser.
@@ -165,6 +169,7 @@ export class BrowserType extends ChannelOwner<channels.BrowserTypeChannel, chann
             }
             browser._didClose();
           };
+          ws.removeEventListener('close', prematureCloseListener);
           ws.addEventListener('close', closeListener);
           browser.on(Events.Browser.Disconnected, () => {
             sharedSelectors._removeChannel(selectorsOwner);
@@ -175,7 +180,7 @@ export class BrowserType extends ChannelOwner<channels.BrowserTypeChannel, chann
         });
         ws.addEventListener('error', event => {
           ws.close();
-          reject(new Error('WebSocket error: ' + event.message));
+          reject(new Error(event.message + '. Most likely ws endpoint is incorrect'));
         });
       });
     }, logger);

test/browsertype-launch-server.spec.ts

@@ -33,6 +33,13 @@ describe('lauch server', (suite, { mode }) => {
     await browserServer.close();
   });
 
+  it('should provide an error when ws endpoint is incorrect', async ({browserType, browserOptions}) => {
+    const browserServer = await browserType.launchServer(browserOptions);
+    const error = await browserType.connect({ wsEndpoint: browserServer.wsEndpoint() + '-foo' }).catch(e => e);
+    await browserServer.close();
+    expect(error.message).toContain('Most likely ws endpoint is incorrect');
+  });
+
   it('should fire "close" event during kill', async ({browserType, browserOptions}) => {
     const order = [];
     const browserServer = await browserType.launchServer(browserOptions);