BackdropUnitTestCase::setUp in core/modules/simpletest/backdrop_web_test_case.php

Sets up unit test environment.

BackdropWebTestCase::prepareEnvironment in core/modules/simpletest/backdrop_web_test_case.php

Prepares the current environment for running the test.

ConfigFileStorage::initializeStorage in core/includes/config.inc

Create a configuration directory, if it does not already exist, and ensure it is writable by the site. Additionally, protect it with a .htaccess file.

FileDirectoryTest::testFileCheckDirectoryHandling in core/modules/simpletest/tests/file.test

Test directory handling functions.

file_example_create_directory_submit in modules/examples/file_example/file_example.module

Submit handler for directory creation.

file_prepare_directory in core/includes/file.inc

Checks that the directory exists and is writable.

image_install in core/modules/image/image.install

Implements hook_install().

image_style_create_derivative in core/modules/image/image.module

Creates a new image derivative based on an image style.

system_requirements in core/modules/system/system.install

Implements hook_requirements().