Merge branch 'develop-ascraeus' into develop

* develop-ascraeus:
  [ticket/11528] Change click_submit() to accept id as param
  [ticket/11528] Handle case when config file cant be written by installer
  [ticket/11528] Change NULL to null
  [ticket/11528] Fix spaces and slashes as per guidelines
  [ticket/11528] Add asserts in installation steps
  [ticket/11528] Use 'use' keyword to import classes to current scope
  [ticket/11528] Move parent::tearDown() to end of tearDown()
  [ticket/11528] Call parent::tearDown in overrided tearDown method
  [ticket/11528] Instantiate $client, $driver from functional test case
  [ticket/11528] Refactor install_board() code into a new class
  [ticket/11528] Add behat/mink and mink-goutte-driver as dependency

tests/functional/fileupload_form_test.php

@@ -42,6 +42,8 @@ class phpbb_functional_fileupload_form_test extends phpbb_functional_test_case
 
 			unlink($fileinfo->getPathname());
 		}
+
+		parent::tearDown();
 	}
 
 	private function upload_file($filename, $mimetype)

tests/functional/fileupload_remote_test.php

@@ -43,6 +43,8 @@ class phpbb_functional_fileupload_remote_test extends phpbb_functional_test_case
 		global $config, $user;
 		$user = null;
 		$config = array();
+
+		parent::tearDown();
 	}
 
 	public function test_invalid_extension()

tests/functional/forgot_password_test.php

@@ -57,5 +57,7 @@ class phpbb_functional_forgot_password_test extends phpbb_functional_test_case
 			'config[allow_password_reset]'	=> 1,
 		));
 		$crawler = self::submit($form);
+
+		parent::tearDown();
 	}
 }

tests/functional/plupload_test.php

@@ -57,6 +57,8 @@ class phpbb_functional_plupload_test extends phpbb_functional_test_case
 
 			unlink($fileinfo->getPathname());
 		}
+
+		parent::tearDown();
 	}
 
 	public function get_urls()