Fixed argument type in switchToIFrame() to be integer.

src/Driver/CoreDriver.php

@@ -160,14 +160,14 @@ public function switchToWindow(?string $name = null)
     }
 
     /**
-     * @param string|null $name
+     * @param int|null $name
      *
      * @return void
      *
      * @throws UnsupportedDriverActionException When operation not supported by the driver
      * @throws DriverException                  When the operation cannot be done
      */
-    public function switchToIFrame(?string $name = null)
+    public function switchToIFrame(?int $name = null)
     {
         throw new UnsupportedDriverActionException('iFrames management is not supported by %s', $this);
     }

src/Driver/DriverInterface.php

@@ -184,14 +184,14 @@ public function switchToWindow(?string $name = null);
     /**
      * Switches to specific iFrame.
      *
-     * @param string|null $name iframe name (null for switching back)
+     * @param int|null $name iframe id (null for switching back)
      *
      * @return void
      *
      * @throws UnsupportedDriverActionException When operation not supported by the driver
      * @throws DriverException                  When the operation cannot be done
      */
-    public function switchToIFrame(?string $name = null);
+    public function switchToIFrame(?int $name = null);
 
     /**
      * Sets specific request header on client.

src/Session.php

@@ -355,11 +355,11 @@ public function switchToWindow(?string $name = null)
     /**
      * Switches to specific iFrame.
      *
-     * @param string|null $name iframe name (null for switching back)
+     * @param int|null $name iframe id (null for switching back)
      *
      * @return void
      */
-    public function switchToIFrame(?string $name = null)
+    public function switchToIFrame(?int $name = null)
     {
         $this->driver->switchToIFrame($name);
     }

tests/SessionTest.php

@@ -300,9 +300,9 @@ public function testSwitchToIFrame()
     {
         $this->driver->expects($this->once())
             ->method('switchToIFrame')
-            ->with('test');
+            ->with(0);
 
-        $this->session->switchToIFrame('test');
+        $this->session->switchToIFrame(0);
     }
 
     public function testExecuteScript()