Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

vendor/behat/mink/tests/Exception/ElementHtmlExceptionTest.php

@@ -0,0 +1,50 @@
+<?php
+
+namespace Behat\Mink\Tests\Exception;
+
+use Behat\Mink\Exception\ElementHtmlException;
+
+class ElementHtmlExceptionTest extends \PHPUnit_Framework_TestCase
+{
+    public function testExceptionToString()
+    {
+        $driver = $this->getMock('Behat\Mink\Driver\DriverInterface');
+        $element = $this->getElementMock();
+
+        $driver->expects($this->any())
+            ->method('getStatusCode')
+            ->will($this->returnValue(200));
+        $driver->expects($this->any())
+            ->method('getCurrentUrl')
+            ->will($this->returnValue('http://localhost/test'));
+
+        $element->expects($this->any())
+            ->method('getOuterHtml')
+            ->will($this->returnValue("<div>\n    <h1>Hello world</h1>\n    <p>Test</p>\n</div>"));
+
+        $expected = <<<'TXT'
+Html error
+
++--[ HTTP/1.1 200 | http://localhost/test | %s ]
+|
+|  <div>
+|      <h1>Hello world</h1>
+|      <p>Test</p>
+|  </div>
+|
+TXT;
+
+        $expected = sprintf($expected.'  ', get_class($driver));
+
+        $exception = new ElementHtmlException('Html error', $driver, $element);
+
+        $this->assertEquals($expected, $exception->__toString());
+    }
+
+    private function getElementMock()
+    {
+        return $this->getMockBuilder('Behat\Mink\Element\NodeElement')
+            ->disableOriginalConstructor()
+            ->getMock();
+    }
+}