code: // Licensed to the Software Freedom Conservancy (SFC) under one
  // or more contributor license agreements.  See the NOTICE file
  // distributed with this work for additional information
  // regarding copyright ownership.  The SFC licenses this file
  // to you under the Apache License, Version 2.0 (the
  // "License"); you may not use this file except in compliance
  // with the License.  You may obtain a copy of the License at
  //
  //   http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing,
  // software distributed under the License is distributed on an
  // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  // KIND, either express or implied.  See the License for the
  // specific language governing permissions and limitations
  // under the License.
  
  package org.openqa.selenium.grid.router;
  
  import static org.assertj.core.api.Assertions.assertThat;
  import static org.assertj.core.api.Assumptions.assumeThat;
  
  import com.google.common.collect.ImmutableMap;
  import java.io.StringReader;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Objects;
  import org.junit.jupiter.api.BeforeAll;
  import org.junit.jupiter.api.Test;
  import org.openqa.selenium.By;
  import org.openqa.selenium.Capabilities;
  import org.openqa.selenium.MutableCapabilities;
  import org.openqa.selenium.WebDriver;
  import org.openqa.selenium.chrome.ChromeOptions;
  import org.openqa.selenium.devtools.DevTools;
  import org.openqa.selenium.devtools.HasDevTools;
  import org.openqa.selenium.devtools.idealized.Network;
  import org.openqa.selenium.grid.config.MapConfig;
  import org.openqa.selenium.grid.config.TomlConfig;
  import org.openqa.selenium.grid.router.DeploymentTypes.Deployment;
  import org.openqa.selenium.grid.server.BaseServerOptions;
  import org.openqa.selenium.grid.server.Server;
  import org.openqa.selenium.netty.server.NettyServer;
  import org.openqa.selenium.remote.Augmenter;
  import org.openqa.selenium.remote.RemoteWebDriver;
  import org.openqa.selenium.remote.http.Contents;
  import org.openqa.selenium.remote.http.HttpResponse;
  import org.openqa.selenium.testing.drivers.Browser;
  
  class DistributedCdpTest {
  
    @BeforeAll
    public static void ensureBrowserIsCdpEnabled() {
      Browser browser = Objects.requireNonNull(Browser.detect());
  
      assumeThat(browser.supportsCdp()).isTrue();
    }
  
    @Test
    void ensureBasicFunctionality() {
      Browser browser = Browser.detect();
  
      Deployment deployment =
          DeploymentTypes.DISTRIBUTED.start(
              browser.getCapabilities(),
              new TomlConfig(
                  new StringReader(
                      "[node]\n"
                          + "selenium-manager = true\n"
                          + "driver-implementation = "
                          + browser.displayName())));
  
      Server<?> server =
          new NettyServer(
                  new BaseServerOptions(new MapConfig(ImmutableMap.of())),
                  req ->
                      new HttpResponse()
                          .setContent(
                              Contents.utf8String(
                                  "<script>document.write(navigator.userAgent);</script><body><h1"
                                      + " id=header>Cheese</h1>")))
              .start();
  
      WebDriver driver =
          new RemoteWebDriver(
              deployment.getServer().getUrl(), addBrowserPath(browser.getCapabilities()));
      driver = new Augmenter().augment(driver);
  
      try (DevTools devTools = ((HasDevTools) driver).getDevTools()) {
        devTools.createSessionIfThereIsNotOne(driver.getWindowHandle());
        Network<?, ?> network = devTools.getDomains().network();
        network.setUserAgent("Cheese-Browser 4000");
  
        driver.get(server.getUrl().toString());
  
        String body = driver.findElement(By.tagName("body")).getText();
        assertThat(body).contains("Cheese-Browser 4000");
      }
    }
  
    private Capabilities addBrowserPath(Capabilities caps) {
      if (Browser.detect() == Browser.CHROME) {
        String binary = System.getProperty("webdriver.chrome.binary");
        if (binary == null) {
          return caps;
        }
  
        MutableCapabilities newCaps = new MutableCapabilities(caps);
        @SuppressWarnings("unchecked")
        Map<String, Object> rawOptions =
            (Map<String, Object>) newCaps.getCapability(ChromeOptions.CAPABILITY);
        HashMap<String, Object> googOptions = new HashMap<>(rawOptions);
        googOptions.put("binary", binary);
        newCaps.setCapability(ChromeOptions.CAPABILITY, googOptions);
        return newCaps;
      }
  
      return caps;
    }
  }
  