find unused port for chromedriver

Author: jakemac53

dwds/chromedriver.exe

@@ -74,10 +74,11 @@ class TestContext {
     enableDebugExtension ??= false;
     autoRun ??= true;
     enableDebugging ??= true;
-    port = await findUnusedPort();
+    var chromeDriverPort = await findUnusedPort();
+    var chromeDriverUrlBase = 'wd/hub';
     try {
-      chromeDriver = await Process.start(
-          'chromedriver$_exeExt', ['--port=4444', '--url-base=wd/hub']);
+      chromeDriver = await Process.start('chromedriver$_exeExt',
+          ['--port=$chromeDriverPort', '--url-base=$chromeDriverUrlBase']);
       // On windows this takes a while to boot up, wait for the first line
       // of stdout as a signal that it is ready.
       await chromeDriver.stdout
@@ -120,10 +121,14 @@ class TestContext {
           ]
         }
       });
-    webDriver =
-        await createDriver(spec: WebDriverSpec.JsonWire, desired: capabilities);
+    webDriver = await createDriver(
+        spec: WebDriverSpec.JsonWire,
+        desired: capabilities,
+        uri: Uri.parse(
+            'http://127.0.0.1:$chromeDriverPort/$chromeDriverUrlBase/'));
     var connection = ChromeConnection('localhost', debugPort);
 
+    port = await findUnusedPort();
     testServer = await TestServer.start(
         port,
         daemonPort(workingDirectory),