Coverage: Don't attempt to read cookies while an alert is open (#6211)

* Add workaround for #1485 - don't attempt to read cookies while an alert is open

* Only apply workaround when module is WebDriver

src/Codeception/Coverage/Subscriber/LocalServer.php

@@ -9,6 +9,7 @@
 use Codeception\Events;
 use Codeception\Exception\ModuleException;
 use Codeception\Exception\RemoteException;
+use Facebook\WebDriver\Exception\NoSuchAlertException;
 
 /**
  * When collecting code coverage data from local server HTTP requests are sent to c3.php file.
@@ -242,6 +243,19 @@ protected function startCoverageCollection($testName)
 
     protected function fetchErrors()
     {
+        // Calling grabCookie() while an alert is present dismisses the alert
+        // @see https://github.com/Codeception/Codeception/issues/1485
+        if ($this->module instanceof \Codeception\Module\WebDriver) {
+            try {
+                $alert = $this->module->webDriver->switchTo()->alert();
+                $alert->getText();
+                // If this succeeds an alert is present, abort
+                return;
+            } catch (NoSuchAlertException $e) {
+                // No alert present, continue
+            }
+        }
+
         try {
             $error = $this->module->grabCookie(self::COVERAGE_COOKIE_ERROR);
         } catch (ModuleException $e) {