first commit

cache/tests/fixtures/cache_phpunit_dummy_datasource_versionable.php

@@ -0,0 +1,84 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * A dummy datasource which supports versioning.
+ *
+ * @package core_cache
+ * @copyright 2021 The Open University
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class cache_phpunit_dummy_datasource_versionable extends cache_phpunit_dummy_datasource
+        implements cache_data_source_versionable {
+    /** @var array Data in cache */
+    protected $data = [];
+
+    /** @var cache_phpunit_dummy_datasource_versionable Last created instance */
+    protected static $lastinstance;
+
+    /**
+     * Returns an instance of this object for use with the cache.
+     *
+     * @param cache_definition $definition
+     * @return cache_phpunit_dummy_datasource New object
+     */
+    public static function get_instance_for_cache(cache_definition $definition):
+            cache_phpunit_dummy_datasource_versionable {
+        self::$lastinstance = new cache_phpunit_dummy_datasource_versionable();
+        return self::$lastinstance;
+    }
+
+    /**
+     * Gets the last instance that was created.
+     *
+     * @return cache_phpunit_dummy_datasource_versionable
+     */
+    public static function get_last_instance(): cache_phpunit_dummy_datasource_versionable {
+        return self::$lastinstance;
+    }
+
+    /**
+     * Sets up the datasource so that it has a value for a particular key.
+     *
+     * @param string $key Key
+     * @param int $version Version for key
+     * @param mixed $data
+     */
+    public function has_value(string $key, int $version, $data): void {
+        $this->data[$key] = new \core_cache\version_wrapper($data, $version);
+    }
+
+    /**
+     * Loads versioned data.
+     *
+     * @param int|string $key Key
+     * @param int $requiredversion Minimum version number
+     * @param mixed $actualversion Should be set to the actual version number retrieved
+     * @return mixed Data retrieved from cache or false if none
+     */
+    public function load_for_cache_versioned($key, int $requiredversion, &$actualversion) {
+        if (!array_key_exists($key, $this->data)) {
+            return false;
+        }
+        $value = $this->data[$key];
+        if ($value->version < $requiredversion) {
+            return false;
+        }
+        $actualversion = $value->version;
+        return $value->data;
+    }
+}
+

cache/tests/fixtures/cachestore_file_with_ttl_wrappers.php

@@ -0,0 +1,37 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * A subclass of cachestore_file but which doesn't report that it has TTL support.
+ *
+ * This is so we can easily test behaviour involving the TTL wrapper objects.
+ *
+ * @package core_cache
+ * @copyright 2021 The Open University
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class cachestore_file_with_ttl_wrappers extends cachestore_file {
+    /**
+     * Reports the same supported features as the parent, but without SUPPORTS_NATIVE_TTL.
+     *
+     * @param array $configuration Configuration
+     * @return int Supported features
+     */
+    public static function get_supported_features(array $configuration = array()) {
+        return parent::get_supported_features($configuration) - self::SUPPORTS_NATIVE_TTL;
+    }
+}
+

cache/tests/fixtures/lib.php

@@ -0,0 +1,600 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Support library for the cache PHPUnit tests.
+ *
+ * This file is part of Moodle's cache API, affectionately called MUC.
+ * It contains the components that are requried in order to use caching.
+ *
+ * @package    core
+ * @category   cache
+ * @copyright  2012 Sam Hemelryk
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+require_once($CFG->dirroot.'/cache/locallib.php');
+
+/**
+ * Override the default cache configuration for our own maniacal purposes.
+ *
+ * This class was originally named cache_config_phpunittest but was renamed in 2.9
+ * because it is used for both unit tests and acceptance tests.
+ *
+ * @since 2.9
+ * @copyright 2012 Sam Hemelryk
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class cache_config_testing extends cache_config_writer {
+
+    /**
+     * Creates the default configuration and saves it.
+     *
+     * This function calls config_save, however it is safe to continue using it afterwards as this function should only ever
+     * be called when there is no configuration file already.
+     *
+     * @param bool $forcesave If set to true then we will forcefully save the default configuration file.
+     * @return true|array Returns true if the default configuration was successfully created.
+     *     Returns a configuration array if it could not be saved. This is a bad situation. Check your error logs.
+     */
+    public static function create_default_configuration($forcesave = false) {
+        global $CFG;
+        // HACK ALERT.
+        // We probably need to come up with a better way to create the default stores, or at least ensure 100% that the
+        // default store plugins are protected from deletion.
+        $writer = new self;
+        $writer->configstores = self::get_default_stores();
+        $writer->configdefinitions = self::locate_definitions();
+        $defaultapplication = 'default_application';
+
+        $appdefine = defined('TEST_CACHE_USING_APPLICATION_STORE') ? TEST_CACHE_USING_APPLICATION_STORE : false;
+        if ($appdefine !== false && preg_match('/^[a-zA-Z][a-zA-Z0-9_]+$/', $appdefine)) {
+            $expectedstore = $appdefine;
+            $file = $CFG->dirroot.'/cache/stores/'.$appdefine.'/lib.php';
+            $class = 'cachestore_'.$appdefine;
+            if (file_exists($file)) {
+                require_once($file);
+            }
+            if (class_exists($class) && $class::ready_to_be_used_for_testing()) {
+                /* @var cache_store $class */
+                $writer->configstores['test_application'] = array(
+                    'name' => 'test_application',
+                    'plugin' => $expectedstore,
+                    'modes' => $class::get_supported_modes(),
+                    'features' => $class::get_supported_features(),
+                    'configuration' => $class::unit_test_configuration()
+                );
+
+                $defaultapplication = 'test_application';
+            }
+        }
+
+        $writer->configmodemappings = array(
+            array(
+                'mode' => cache_store::MODE_APPLICATION,
+                'store' => $defaultapplication,
+                'sort' => -1
+            ),
+            array(
+                'mode' => cache_store::MODE_SESSION,
+                'store' => 'default_session',
+                'sort' => -1
+            ),
+            array(
+                'mode' => cache_store::MODE_REQUEST,
+                'store' => 'default_request',
+                'sort' => -1
+            )
+        );
+        $writer->configlocks = array(
+            'default_file_lock' => array(
+                'name' => 'cachelock_file_default',
+                'type' => 'cachelock_file',
+                'dir' => 'filelocks',
+                'default' => true
+            )
+        );
+
+        $factory = cache_factory::instance();
+        // We expect the cache to be initialising presently. If its not then something has gone wrong and likely
+        // we are now in a loop.
+        if (!$forcesave && $factory->get_state() !== cache_factory::STATE_INITIALISING) {
+            return $writer->generate_configuration_array();
+        }
+        $factory->set_state(cache_factory::STATE_SAVING);
+        $writer->config_save();
+        return true;
+    }
+
+    /**
+     * Returns the expected path to the configuration file.
+     *
+     * We override this function to add handling for $CFG->altcacheconfigpath.
+     * We want to support it so that people can run unit tests against alternative cache setups.
+     * However we don't want to ever make changes to the file at $CFG->altcacheconfigpath so we
+     * always use dataroot and copy the alt file there as required.
+     *
+     * @throws cache_exception
+     * @return string The absolute path
+     */
+    protected static function get_config_file_path() {
+        global $CFG;
+        // We always use this path.
+        $configpath = $CFG->dataroot.'/muc/config.php';
+
+        if (!empty($CFG->altcacheconfigpath)) {
+
+            // No need to check we are within a test here, this is the cache config class that gets used
+            // only when one of those is true.
+            if  (!defined('TEST_CACHE_USING_ALT_CACHE_CONFIG_PATH') || !TEST_CACHE_USING_ALT_CACHE_CONFIG_PATH) {
+                // TEST_CACHE_USING_ALT_CACHE_CONFIG_PATH has not being defined or is false, we want to use the default.
+                return $configpath;
+            }
+
+            $path = $CFG->altcacheconfigpath;
+            if (is_dir($path) && is_writable($path)) {
+                // Its a writable directory, thats fine. Convert it to a file.
+                $path = $CFG->altcacheconfigpath.'/cacheconfig.php';
+            }
+            if (is_readable($path)) {
+                $directory = dirname($configpath);
+                if ($directory !== $CFG->dataroot && !file_exists($directory)) {
+                    $result = make_writable_directory($directory, false);
+                    if (!$result) {
+                        throw new cache_exception('ex_configcannotsave', 'cache', '', null, 'Cannot create config directory. Check the permissions on your moodledata directory.');
+                    }
+                }
+                // We don't care that this fails but we should let the developer know.
+                if (!is_readable($configpath) && !@copy($path, $configpath)) {
+                    debugging('Failed to copy alt cache config file to required location');
+                }
+            }
+        }
+
+        // We always use the dataroot location.
+        return $configpath;
+    }
+
+    /**
+     * Adds a definition to the stack
+     * @param string $area
+     * @param array $properties
+     * @param bool $addmapping By default this method adds a definition and a mapping for that definition. You can
+     *    however set this to false if you only want it to add the definition and not the mapping.
+     */
+    public function phpunit_add_definition($area, array $properties, $addmapping = true) {
+        if (!array_key_exists('overrideclass', $properties)) {
+            switch ($properties['mode']) {
+                case cache_store::MODE_APPLICATION:
+                    $properties['overrideclass'] = 'cache_phpunit_application';
+                    break;
+                case cache_store::MODE_SESSION:
+                    $properties['overrideclass'] = 'cache_phpunit_session';
+                    break;
+                case cache_store::MODE_REQUEST:
+                    $properties['overrideclass'] = 'cache_phpunit_request';
+                    break;
+            }
+        }
+        $this->configdefinitions[$area] = $properties;
+        if ($addmapping) {
+            switch ($properties['mode']) {
+                case cache_store::MODE_APPLICATION:
+                    $this->phpunit_add_definition_mapping($area, 'default_application', 0);
+                    break;
+                case cache_store::MODE_SESSION:
+                    $this->phpunit_add_definition_mapping($area, 'default_session', 0);
+                    break;
+                case cache_store::MODE_REQUEST:
+                    $this->phpunit_add_definition_mapping($area, 'default_request', 0);
+                    break;
+            }
+        }
+    }
+
+    /**
+     * Removes a definition.
+     * @param string $name
+     */
+    public function phpunit_remove_definition($name) {
+        unset($this->configdefinitions[$name]);
+    }
+
+    /**
+     * Removes the configured stores so that there are none available.
+     */
+    public function phpunit_remove_stores() {
+        $this->configstores = array();
+    }
+
+    /**
+     * Forcefully adds a file store.
+     *
+     * You can turn off native TTL support if you want a way to test TTL wrapper objects.
+     *
+     * @param string $name
+     * @param bool $nativettl If false, uses fixture that turns off native TTL support
+     */
+    public function phpunit_add_file_store(string $name, bool $nativettl = true): void {
+        if (!$nativettl) {
+            require_once(__DIR__ . '/cachestore_file_with_ttl_wrappers.php');
+        }
+        $this->configstores[$name] = array(
+            'name' => $name,
+            'plugin' => 'file',
+            'configuration' => array(
+                'path' => ''
+            ),
+            'features' => 6,
+            'modes' => 3,
+            'mappingsonly' => false,
+            'class' => $nativettl ? 'cachestore_file' : 'cachestore_file_with_ttl_wrappers',
+            'default' => false,
+            'lock' => 'cachelock_file_default'
+        );
+    }
+
+    /**
+     * Hacks the in-memory configuration for a store.
+     *
+     * @param string $store Name of store to edit e.g. 'default_application'
+     * @param array $configchanges List of config changes
+     */
+    public function phpunit_edit_store_config(string $store, array $configchanges): void {
+        foreach ($configchanges as $name => $value) {
+            $this->configstores[$store]['configuration'][$name] = $value;
+        }
+    }
+
+    /**
+     * Forcefully adds a session store.
+     *
+     * @param string $name
+     */
+    public function phpunit_add_session_store($name) {
+        $this->configstores[$name] = array(
+            'name' => $name,
+            'plugin' => 'session',
+            'configuration' => array(),
+            'features' => 14,
+            'modes' => 2,
+            'default' => true,
+            'class' => 'cachestore_session',
+            'lock' => 'cachelock_file_default',
+        );
+    }
+
+    /**
+     * Forcefully injects a definition => store mapping.
+     *
+     * This function does no validation, you should only be calling if it you know
+     * exactly what to expect.
+     *
+     * @param string $definition
+     * @param string $store
+     * @param int $sort
+     */
+    public function phpunit_add_definition_mapping($definition, $store, $sort) {
+        $this->configdefinitionmappings[] = array(
+            'store' => $store,
+            'definition' => $definition,
+            'sort' => (int)$sort
+        );
+    }
+
+    /**
+     * Overrides the default site identifier used by the Cache API so that we can be sure of what it is.
+     *
+     * @return string
+     */
+    public function get_site_identifier() {
+        global $CFG;
+        return $CFG->wwwroot.'phpunit';
+    }
+
+    /**
+     * Checks if the configuration file exists.
+     *
+     * @return bool True if it exists
+     */
+    public static function config_file_exists() {
+        // Allow for late static binding by using static.
+        $configfilepath = static::get_config_file_path();
+
+        // Invalidate opcode php cache, so we get correct status of file.
+        core_component::invalidate_opcode_php_cache($configfilepath);
+        return file_exists($configfilepath);
+    }
+}
+
+
+/**
+ * Dummy object for testing cacheable object interface and interaction
+ *
+ * Wake from cache needs specific testing at times to ensure that during multiple
+ * cache get() requests it's possible to verify that it's getting woken each time.
+ *
+ * @copyright  2012 Sam Hemelryk
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class cache_phpunit_dummy_object extends stdClass implements cacheable_object {
+    /**
+     * Test property 1
+     * @var string
+     */
+    public $property1;
+    /**
+     * Test property 1
+     * @var string
+     */
+    public $property2;
+    /**
+     * Test property time for verifying wake is run at each get() call.
+     * @var float
+     */
+    public $propertytime;
+    /**
+     * Constructor
+     * @param string $property1
+     * @param string $property2
+     */
+    public function __construct($property1, $property2, $propertytime = null) {
+        $this->property1 = $property1;
+        $this->property2 = $property2;
+        $this->propertytime = $propertytime === null ? microtime(true) : $propertytime;
+    }
+    /**
+     * Prepares this object for caching
+     * @return array
+     */
+    public function prepare_to_cache() {
+        return array($this->property1.'_ptc', $this->property2.'_ptc', $this->propertytime);
+    }
+    /**
+     * Returns this object from the cache
+     * @param array $data
+     * @return cache_phpunit_dummy_object
+     */
+    public static function wake_from_cache($data) {
+        $time = null;
+        if (!is_null($data[2])) {
+            // Windows 32bit microtime() resolution is 15ms, we ensure the time has moved forward.
+            do {
+                $time = microtime(true);
+            } while ($time == $data[2]);
+
+        }
+        return new cache_phpunit_dummy_object(array_shift($data).'_wfc', array_shift($data).'_wfc', $time);
+    }
+}
+
+/**
+ * Dummy data source object for testing data source interface and implementation
+ *
+ * @copyright  2012 Sam Hemelryk
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class cache_phpunit_dummy_datasource implements cache_data_source {
+    /**
+     * Returns an instance of this object for use with the cache.
+     *
+     * @param cache_definition $definition
+     * @return cache_phpunit_dummy_datasource
+     */
+    public static function get_instance_for_cache(cache_definition $definition) {
+        return new cache_phpunit_dummy_datasource();
+    }
+
+    /**
+     * Loads a key for the cache.
+     *
+     * @param string $key
+     * @return string
+     */
+    public function load_for_cache($key) {
+        return $key.' has no value really.';
+    }
+
+    /**
+     * Loads many keys for the cache
+     *
+     * @param array $keys
+     * @return array
+     */
+    public function load_many_for_cache(array $keys) {
+        $return = array();
+        foreach ($keys as $key) {
+            $return[$key] = $key.' has no value really.';
+        }
+        return $return;
+    }
+}
+
+/**
+ * PHPUnit application cache loader.
+ *
+ * Used to expose things we could not otherwise see within an application cache.
+ *
+ * @copyright  2012 Sam Hemelryk
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class cache_phpunit_application extends cache_application {
+
+    /**
+     * Returns the class of the store immediately associated with this cache.
+     * @return string
+     */
+    public function phpunit_get_store_class() {
+        return get_class($this->get_store());
+    }
+
+    /**
+     * Returns all the interfaces the cache store implements.
+     * @return array
+     */
+    public function phpunit_get_store_implements() {
+        return class_implements($this->get_store());
+    }
+
+    /**
+     * Returns the given key directly from the static acceleration array.
+     *
+     * @param string $key
+     * @return false|mixed
+     */
+    public function phpunit_static_acceleration_get($key) {
+        return $this->static_acceleration_get($key);
+    }
+
+    /**
+     * Purges only the static acceleration while leaving the rest of the store in tack.
+     *
+     * Used for behaving like you have loaded 2 pages, and reset static while the backing store
+     * still contains all the same data.
+     *
+     */
+    public function phpunit_static_acceleration_purge() {
+        $this->static_acceleration_purge();
+    }
+}
+
+/**
+ * PHPUnit session cache loader.
+ *
+ * Used to expose things we could not otherwise see within an session cache.
+ *
+ * @copyright  2012 Sam Hemelryk
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class cache_phpunit_session extends cache_session {
+
+    /** @var Static member used for emulating the behaviour of session_id() during the tests. */
+    protected static $sessionidmockup = 'phpunitmockupsessionid';
+
+    /**
+     * Returns the class of the store immediately associated with this cache.
+     * @return string
+     */
+    public function phpunit_get_store_class() {
+        return get_class($this->get_store());
+    }
+
+    /**
+     * Returns all the interfaces the cache store implements.
+     * @return array
+     */
+    public function phpunit_get_store_implements() {
+        return class_implements($this->get_store());
+    }
+
+    /**
+     * Provide access to the {@link cache_session::get_key_prefix()} method.
+     *
+     * @return string
+     */
+    public function phpunit_get_key_prefix() {
+        return $this->get_key_prefix();
+    }
+
+    /**
+     * Allows to inject the session identifier.
+     *
+     * @param string $sessionid
+     */
+    public static function phpunit_mockup_session_id($sessionid) {
+        static::$sessionidmockup = $sessionid;
+    }
+
+    /**
+     * Override the parent behaviour so that it does not need the actual session_id() call.
+     */
+    protected function set_session_id() {
+        $this->sessionid = static::$sessionidmockup;
+    }
+}
+
+/**
+ * PHPUnit request cache loader.
+ *
+ * Used to expose things we could not otherwise see within an request cache.
+ *
+ * @copyright  2012 Sam Hemelryk
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class cache_phpunit_request extends cache_request {
+
+    /**
+     * Returns the class of the store immediately associated with this cache.
+     * @return string
+     */
+    public function phpunit_get_store_class() {
+        return get_class($this->get_store());
+    }
+
+    /**
+     * Returns all the interfaces the cache store implements.
+     * @return array
+     */
+    public function phpunit_get_store_implements() {
+        return class_implements($this->get_store());
+    }
+}
+
+/**
+ * Dummy overridden cache loader class that we can use to test overriding loader functionality.
+ *
+ * @copyright  2012 Sam Hemelryk
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class cache_phpunit_dummy_overrideclass extends cache_application {
+    // Satisfying the code pre-checker is just part of my day job.
+}
+
+/**
+ * Cache PHPUnit specific factory.
+ *
+ * @copyright  2012 Sam Hemelryk
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class cache_phpunit_factory extends cache_factory {
+    /**
+     * Exposes the cache_factory's disable method.
+     *
+     * Perhaps one day that method will be made public, for the time being it is protected.
+     */
+    public static function phpunit_disable() {
+        parent::disable();
+    }
+}
+
+/**
+ * Cache PHPUnit specific Cache helper.
+ *
+ * @copyright  2018 Andrew Nicols <andrew@nicols.co.uk>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class cache_phpunit_cache extends cache {
+    /**
+     * Make the changes which simulate a new request within the cache.
+     * This essentially resets currently held static values in the class, and increments the current timestamp.
+     */
+    public static function simulate_new_request() {
+        self::$now += 0.1;
+        self::$purgetoken = null;
+    }
+}

cache/tests/fixtures/stores.php

@@ -0,0 +1,193 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Cache store test fixtures.
+ *
+ * @package    core
+ * @category   cache
+ * @copyright  2013 Sam Hemelryk
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * An abstract class to make writing unit tests for cache stores very easy.
+ *
+ * @package    core
+ * @category   cache
+ * @copyright  2013 Sam Hemelryk
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+abstract class cachestore_tests extends advanced_testcase {
+
+    /**
+     * Returns the class name for the store.
+     *
+     * @return string
+     */
+    abstract protected function get_class_name();
+
+    /**
+     * Sets up the fixture, for example, open a network connection.
+     * This method is called before a test is executed.
+     */
+    public function setUp(): void {
+        $class = $this->get_class_name();
+        if (!class_exists($class) || !$class::are_requirements_met()) {
+            $this->markTestSkipped('Could not test '.$class.'. Requirements are not met.');
+        }
+        parent::setUp();
+    }
+    /**
+     * Run the unit tests for the store.
+     */
+    public function test_test_instance() {
+        $class = $this->get_class_name();
+
+        $modes = $class::get_supported_modes();
+        if ($modes & cache_store::MODE_APPLICATION) {
+            $definition = cache_definition::load_adhoc(cache_store::MODE_APPLICATION, $class, 'phpunit_test');
+            $instance = new $class($class.'_test', $class::unit_test_configuration());
+
+            if (!$instance->is_ready()) {
+                $this->markTestSkipped('Could not test '.$class.'. No test instance configured for application caches.');
+            } else {
+                $instance->initialise($definition);
+                $this->run_tests($instance);
+            }
+        }
+        if ($modes & cache_store::MODE_SESSION) {
+            $definition = cache_definition::load_adhoc(cache_store::MODE_SESSION, $class, 'phpunit_test');
+            $instance = new $class($class.'_test', $class::unit_test_configuration());
+
+            if (!$instance->is_ready()) {
+                $this->markTestSkipped('Could not test '.$class.'. No test instance configured for session caches.');
+            } else {
+                $instance->initialise($definition);
+                $this->run_tests($instance);
+            }
+        }
+        if ($modes & cache_store::MODE_REQUEST) {
+            $definition = cache_definition::load_adhoc(cache_store::MODE_REQUEST, $class, 'phpunit_test');
+            $instance = new $class($class.'_test', $class::unit_test_configuration());
+
+            if (!$instance->is_ready()) {
+                $this->markTestSkipped('Could not test '.$class.'. No test instance configured for request caches.');
+            } else {
+                $instance->initialise($definition);
+                $this->run_tests($instance);
+            }
+        }
+    }
+
+    /**
+     * Test the store for basic functionality.
+     */
+    public function run_tests(cache_store $instance) {
+        $object = new stdClass;
+        $object->data = 1;
+
+        // Test set with a string.
+        $this->assertTrue($instance->set('test1', 'test1'));
+        $this->assertTrue($instance->set('test2', 'test2'));
+        $this->assertTrue($instance->set('test3', '3'));
+        $this->assertTrue($instance->set('other3', '3'));
+
+        // Test get with a string.
+        $this->assertSame('test1', $instance->get('test1'));
+        $this->assertSame('test2', $instance->get('test2'));
+        $this->assertSame('3', $instance->get('test3'));
+
+        // Test find and find with prefix if this class implements the searchable interface.
+        if ($instance->is_searchable()) {
+            // Extra settings here ignore the return order of the array.
+            $this->assertEqualsCanonicalizing(['test3', 'test1', 'test2', 'other3'], $instance->find_all());
+
+            // Extra settings here ignore the return order of the array.
+            $this->assertEqualsCanonicalizing(['test2', 'test1', 'test3'], $instance->find_by_prefix('test'));
+            $this->assertEquals(['test2'], $instance->find_by_prefix('test2'));
+            $this->assertEquals(['other3'], $instance->find_by_prefix('other'));
+            $this->assertEquals([], $instance->find_by_prefix('nothere'));
+        }
+
+        // Test set with an int.
+        $this->assertTrue($instance->set('test1', 1));
+        $this->assertTrue($instance->set('test2', 2));
+
+        // Test get with an int.
+        $this->assertSame(1, $instance->get('test1'));
+        $this->assertIsInt($instance->get('test1'));
+        $this->assertSame(2, $instance->get('test2'));
+        $this->assertIsInt($instance->get('test2'));
+
+        // Test set with a bool.
+        $this->assertTrue($instance->set('test1', true));
+
+        // Test get with an bool.
+        $this->assertSame(true, $instance->get('test1'));
+        $this->assertIsBool($instance->get('test1'));
+
+        // Test with an object.
+        $this->assertTrue($instance->set('obj', $object));
+        if ($instance::get_supported_features() & cache_store::DEREFERENCES_OBJECTS) {
+            $this->assertNotSame($object, $instance->get('obj'), 'Objects must be dereferenced when returned.');
+        }
+        $this->assertEquals($object, $instance->get('obj'));
+
+        // Test delete.
+        $this->assertTrue($instance->delete('test1'));
+        $this->assertTrue($instance->delete('test3'));
+        $this->assertFalse($instance->delete('test3'));
+        $this->assertFalse($instance->get('test1'));
+        $this->assertSame(2, $instance->get('test2'));
+        $this->assertTrue($instance->set('test1', 'test1'));
+
+        // Test purge.
+        $this->assertTrue($instance->purge());
+        $this->assertFalse($instance->get('test1'));
+        $this->assertFalse($instance->get('test2'));
+
+        // Test set_many.
+        $outcome = $instance->set_many(array(
+            array('key' => 'many1', 'value' => 'many1'),
+            array('key' => 'many2', 'value' => 'many2'),
+            array('key' => 'many3', 'value' => 'many3'),
+            array('key' => 'many4', 'value' => 'many4'),
+            array('key' => 'many5', 'value' => 'many5')
+        ));
+        $this->assertSame(5, $outcome);
+        $this->assertSame('many1', $instance->get('many1'));
+        $this->assertSame('many5', $instance->get('many5'));
+        $this->assertFalse($instance->get('many6'));
+
+        // Test get_many.
+        $result = $instance->get_many(array('many1', 'many3', 'many5', 'many6'));
+        $this->assertIsArray($result);
+        $this->assertCount(4, $result);
+        $this->assertSame(array(
+            'many1' => 'many1',
+            'many3' => 'many3',
+            'many5' => 'many5',
+            'many6' => false,
+        ), $result);
+
+        // Test delete_many.
+        $this->assertSame(3, $instance->delete_many(array('many2', 'many3', 'many4')));
+        $this->assertSame(2, $instance->delete_many(array('many1', 'many5', 'many6')));
+    }
+}