Merge branch 'MDL-63712-master' of git://github.com/mickhawkins/moodle
authorAndrew Nicols <andrew@nicols.co.uk>
Mon, 5 Nov 2018 01:33:42 +0000 (09:33 +0800)
committerAndrew Nicols <andrew@nicols.co.uk>
Mon, 5 Nov 2018 01:33:42 +0000 (09:33 +0800)
message/classes/privacy/provider.php
message/tests/privacy_provider_test.php

index b9049e5..5c24544 100644 (file)
@@ -18,6 +18,7 @@
  * Privacy Subsystem implementation for core_message.
  *
  * @package    core_message
+ * @category   privacy
  * @copyright  2018 Mark Nelson <markn@moodle.com>
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
@@ -25,8 +26,10 @@ namespace core_message\privacy;
 
 use core_privacy\local\metadata\collection;
 use core_privacy\local\request\approved_contextlist;
+use core_privacy\local\request\approved_userlist;
 use core_privacy\local\request\contextlist;
 use core_privacy\local\request\transform;
+use core_privacy\local\request\userlist;
 use core_privacy\local\request\writer;
 
 defined('MOODLE_INTERNAL') || die();
@@ -40,7 +43,8 @@ defined('MOODLE_INTERNAL') || die();
 class provider implements
     \core_privacy\local\metadata\provider,
     \core_privacy\local\request\subsystem\provider,
-    \core_privacy\local\request\user_preference_provider {
+    \core_privacy\local\request\user_preference_provider,
+    \core_privacy\local\request\core_userlist_provider {
 
     /**
      * Return the fields which contain personal data.
@@ -175,13 +179,72 @@ class provider implements
      * @return contextlist the list of contexts containing user info for the user.
      */
     public static function get_contexts_for_userid(int $userid) : contextlist {
-        // Messages are in the system context.
+        global $DB;
+
         $contextlist = new contextlist();
-        $contextlist->add_system_context();
+
+        // Messages are in the user context.
+        // For the sake of performance, there is no need to call add_from_sql for each of the below cases.
+        // It is enough to add the user's context as soon as we come to the conclusion that the user has some data.
+        // Also, the order of checking is sorted by the probability of occurrence (just by guess).
+        // There is no need to check the message_user_actions table, as there needs to be a message in order to be a message action.
+        // So, checking messages table would suffice.
+
+        $hasdata = false;
+        $hasdata = $hasdata || $DB->record_exists_select('notifications', 'useridfrom = ? OR useridto = ?', [$userid, $userid]);
+        $hasdata = $hasdata || $DB->record_exists('message_conversation_members', ['userid' => $userid]);
+        $hasdata = $hasdata || $DB->record_exists('messages', ['useridfrom' => $userid]);
+        $hasdata = $hasdata || $DB->record_exists_select('message_contacts', 'userid = ? OR contactid = ?', [$userid, $userid]);
+        $hasdata = $hasdata || $DB->record_exists_select('message_users_blocked', 'userid = ? OR blockeduserid = ?',
+                [$userid, $userid]);
+        $hasdata = $hasdata || $DB->record_exists_select('message_contact_requests', 'userid = ? OR requesteduserid = ?',
+                [$userid, $userid]);
+
+        if ($hasdata) {
+            $contextlist->add_user_context($userid);
+        }
 
         return $contextlist;
     }
 
+    /**
+     * Get the list of users who have data within a context.
+     *
+     * @param   userlist    $userlist   The userlist containing the list of users who have data in this context/plugin combination.
+     */
+    public static function get_users_in_context(userlist $userlist) {
+        global $DB;
+
+        $context = $userlist->get_context();
+
+        if (!$context instanceof \context_user) {
+            return;
+        }
+
+        $userid = $context->instanceid;
+
+        // Messages are in the user context.
+        // For the sake of performance, there is no need to call add_from_sql for each of the below cases.
+        // It is enough to add the user's context as soon as we come to the conclusion that the user has some data.
+        // Also, the order of checking is sorted by the probability of occurrence (just by guess).
+        // There is no need to check the message_user_actions table, as there needs to be a message in order to be a message action.
+        // So, checking messages table would suffice.
+
+        $hasdata = false;
+        $hasdata = $hasdata || $DB->record_exists_select('notifications', 'useridfrom = ? OR useridto = ?', [$userid, $userid]);
+        $hasdata = $hasdata || $DB->record_exists('message_conversation_members', ['userid' => $userid]);
+        $hasdata = $hasdata || $DB->record_exists('messages', ['useridfrom' => $userid]);
+        $hasdata = $hasdata || $DB->record_exists_select('message_contacts', 'userid = ? OR contactid = ?', [$userid, $userid]);
+        $hasdata = $hasdata || $DB->record_exists_select('message_users_blocked', 'userid = ? OR blockeduserid = ?',
+                        [$userid, $userid]);
+        $hasdata = $hasdata || $DB->record_exists_select('message_contact_requests', 'userid = ? OR requesteduserid = ?',
+                        [$userid, $userid]);
+
+        if ($hasdata) {
+            $userlist->add_user($userid);
+        }
+    }
+
     /**
      * Export personal data for the given approved_contextlist. User and context information is contained within the contextlist.
      *
@@ -192,17 +255,17 @@ class provider implements
             return;
         }
 
-        // Remove non-system contexts. If it ends up empty then early return.
-        $contexts = array_filter($contextlist->get_contexts(), function($context) {
-            return $context->contextlevel == CONTEXT_SYSTEM;
+        $userid = $contextlist->get_user()->id;
+
+        // Remove non-user and invalid contexts. If it ends up empty then early return.
+        $contexts = array_filter($contextlist->get_contexts(), function($context) use($userid) {
+            return $context->contextlevel == CONTEXT_USER && $context->instanceid == $userid;
         });
 
         if (empty($contexts)) {
             return;
         }
 
-        $userid = $contextlist->get_user()->id;
-
         // Export the contacts.
         self::export_user_data_contacts($userid);
 
@@ -225,19 +288,9 @@ class provider implements
      * @param \context $context the context to delete in.
      */
     public static function delete_data_for_all_users_in_context(\context $context) {
-        global $DB;
-
-        if (!$context instanceof \context_system) {
-            return;
+        if ($context instanceof \context_user) {
+            static::delete_user_data($context->instanceid);
         }
-
-        $DB->delete_records('messages');
-        $DB->delete_records('message_user_actions');
-        $DB->delete_records('message_conversation_members');
-        $DB->delete_records('message_contacts');
-        $DB->delete_records('message_contact_requests');
-        $DB->delete_records('message_users_blocked');
-        $DB->delete_records('notifications');
     }
 
     /**
@@ -246,22 +299,55 @@ class provider implements
      * @param approved_contextlist $contextlist a list of contexts approved for deletion.
      */
     public static function delete_data_for_user(approved_contextlist $contextlist) {
-        global $DB;
-
         if (empty($contextlist->count())) {
             return;
         }
 
-        // Remove non-system contexts. If it ends up empty then early return.
-        $contexts = array_filter($contextlist->get_contexts(), function($context) {
-            return $context->contextlevel == CONTEXT_SYSTEM;
+        $userid = $contextlist->get_user()->id;
+
+        // Remove non-user and invalid contexts. If it ends up empty then early return.
+        $contexts = array_filter($contextlist->get_contexts(), function($context) use($userid) {
+            return $context->contextlevel == CONTEXT_USER && $context->instanceid == $userid;
         });
 
         if (empty($contexts)) {
             return;
         }
 
-        $userid = $contextlist->get_user()->id;
+        static::delete_user_data($userid);
+    }
+
+    /**
+     * Delete multiple users within a single context.
+     *
+     * @param   approved_userlist       $userlist The approved context and user information to delete information for.
+     */
+    public static function delete_data_for_users(approved_userlist $userlist) {
+        $context = $userlist->get_context();
+
+        if (!$context instanceof \context_user) {
+            return;
+        }
+
+        // Remove invalid users. If it ends up empty then early return.
+        $userids = array_filter($userlist->get_userids(), function($userid) use($context) {
+            return $context->instanceid == $userid;
+        });
+
+        if (empty($userids)) {
+            return;
+        }
+
+        static::delete_user_data($context->instanceid);
+    }
+
+    /**
+     * Delete all user data for the specified user.
+     *
+     * @param int $userid The user id
+     */
+    protected static function delete_user_data(int $userid) {
+        global $DB;
 
         $DB->delete_records('messages', ['useridfrom' => $userid]);
         $DB->delete_records('message_user_actions', ['userid' => $userid]);
@@ -280,7 +366,7 @@ class provider implements
     protected static function export_user_data_contacts(int $userid) {
         global $DB;
 
-        $context = \context_system::instance();
+        $context = \context_user::instance($userid);
 
         // Get the user's contacts.
         if ($contacts = $DB->get_records_select('message_contacts', 'userid = ? OR contactid = ?', [$userid, $userid], 'id ASC')) {
@@ -302,7 +388,7 @@ class provider implements
     protected static function export_user_data_contact_requests(int $userid) {
         global $DB;
 
-        $context = \context_system::instance();
+        $context = \context_user::instance($userid);
 
         if ($contactrequests = $DB->get_records_select('message_contact_requests', 'userid = ? OR requesteduserid = ?',
                 [$userid, $userid], 'id ASC')) {
@@ -334,7 +420,7 @@ class provider implements
     protected static function export_user_data_blocked_users(int $userid) {
         global $DB;
 
-        $context = \context_system::instance();
+        $context = \context_user::instance($userid);
 
         if ($blockedusers = $DB->get_records('message_users_blocked', ['userid' => $userid], 'id ASC')) {
             $blockedusersdata = [];
@@ -355,7 +441,7 @@ class provider implements
     protected static function export_user_data_messages(int $userid) {
         global $DB;
 
-        $context = \context_system::instance();
+        $context = \context_user::instance($userid);
 
         $sql = "SELECT DISTINCT mcm.conversationid as id
                   FROM {message_conversation_members} mcm
@@ -427,7 +513,7 @@ class provider implements
     protected static function export_user_data_notifications(int $userid) {
         global $DB;
 
-        $context = \context_system::instance();
+        $context = \context_user::instance($userid);
 
         $notificationdata = [];
         $select = "useridfrom = ? OR useridto = ?";
index 2e15a7b..101adbb 100644 (file)
@@ -192,16 +192,184 @@ class core_message_privacy_provider_testcase extends \core_privacy\tests\provide
     }
 
     /**
-     * Test for provider::get_contexts_for_userid().
+     * Test for provider::get_contexts_for_userid() when there is no message or notification.
      */
-    public function test_get_contexts_for_userid() {
+    public function test_get_contexts_for_userid_no_data() {
         $this->resetAfterTest();
 
         $user = $this->getDataGenerator()->create_user();
         $contextlist = provider::get_contexts_for_userid($user->id);
+        $this->assertEmpty($contextlist);
+    }
+
+    /**
+     * Test for provider::get_contexts_for_userid() when there is a message between users.
+     */
+    public function test_get_contexts_for_userid_with_message() {
+        $this->resetAfterTest();
+
+        $user1 = $this->getDataGenerator()->create_user();
+        $user2 = $this->getDataGenerator()->create_user();
+
+        // Test nothing is found before message is sent.
+        $contextlist = provider::get_contexts_for_userid($user1->id);
+        $this->assertCount(0, $contextlist);
+        $contextlist = provider::get_contexts_for_userid($user2->id);
+        $this->assertCount(0, $contextlist);
+
+        $this->create_message($user1->id, $user2->id, time() - (9 * DAYSECS));
+
+        // Test for the sender.
+        $contextlist = provider::get_contexts_for_userid($user1->id);
+        $this->assertCount(1, $contextlist);
+        $contextforuser = $contextlist->current();
+        $this->assertEquals(
+                context_user::instance($user1->id)->id,
+                $contextforuser->id);
+
+        // Test for the receiver.
+        $contextlist = provider::get_contexts_for_userid($user2->id);
+        $this->assertCount(1, $contextlist);
+        $contextforuser = $contextlist->current();
+        $this->assertEquals(
+                context_user::instance($user2->id)->id,
+                $contextforuser->id);
+    }
+
+    /**
+     * Test for provider::get_contexts_for_userid() when there is a notification between users.
+     */
+    public function test_get_contexts_for_userid_with_notification() {
+        $this->resetAfterTest();
+
+        $user1 = $this->getDataGenerator()->create_user();
+        $user2 = $this->getDataGenerator()->create_user();
+
+        // Test nothing is found before notification is created.
+        $contextlist = provider::get_contexts_for_userid($user1->id);
+        $this->assertCount(0, $contextlist);
+        $contextlist = provider::get_contexts_for_userid($user2->id);
+        $this->assertCount(0, $contextlist);
+
+        $this->create_notification($user1->id, $user2->id, time() - (9 * DAYSECS));
+
+        // Test for the sender.
+        $contextlist = provider::get_contexts_for_userid($user1->id);
+        $this->assertCount(1, $contextlist);
+        $contextforuser = $contextlist->current();
+        $this->assertEquals(
+                context_user::instance($user1->id)->id,
+                $contextforuser->id);
+
+        // Test for the receiver.
+        $contextlist = provider::get_contexts_for_userid($user2->id);
+        $this->assertCount(1, $contextlist);
+        $contextforuser = $contextlist->current();
+        $this->assertEquals(
+                context_user::instance($user2->id)->id,
+                $contextforuser->id);
+    }
+
+    /**
+     * Test for provider::get_contexts_for_userid() when a users has a contact.
+     */
+    public function test_get_contexts_for_userid_with_contact() {
+        $this->resetAfterTest();
+
+        $user1 = $this->getDataGenerator()->create_user();
+        $user2 = $this->getDataGenerator()->create_user();
+
+        // Test nothing is found before contact is created.
+        $contextlist = provider::get_contexts_for_userid($user1->id);
+        $this->assertCount(0, $contextlist);
+        $contextlist = provider::get_contexts_for_userid($user2->id);
+        $this->assertCount(0, $contextlist);
+
+        \core_message\api::add_contact($user1->id, $user2->id);
+
+        // Test for the user adding the contact.
+        $contextlist = provider::get_contexts_for_userid($user1->id);
+        $this->assertCount(1, $contextlist);
+        $contextforuser = $contextlist->current();
+        $this->assertEquals(
+                context_user::instance($user1->id)->id,
+                $contextforuser->id);
+
+        // Test for the user who is the contact.
+        $contextlist = provider::get_contexts_for_userid($user2->id);
+        $this->assertCount(1, $contextlist);
+        $contextforuser = $contextlist->current();
+        $this->assertEquals(
+                context_user::instance($user2->id)->id,
+                $contextforuser->id);
+    }
+
+    /**
+     * Test for provider::get_contexts_for_userid() when a user makes a contact request.
+     */
+    public function test_get_contexts_for_userid_with_contact_request() {
+        $this->resetAfterTest();
+
+        $user1 = $this->getDataGenerator()->create_user();
+        $user2 = $this->getDataGenerator()->create_user();
+
+        // Test nothing is found before request is created.
+        $contextlist = provider::get_contexts_for_userid($user1->id);
+        $this->assertCount(0, $contextlist);
+        $contextlist = provider::get_contexts_for_userid($user2->id);
+        $this->assertCount(0, $contextlist);
+
+        \core_message\api::create_contact_request($user1->id, $user2->id);
+
+        // Test for the user requesting the contact.
+        $contextlist = provider::get_contexts_for_userid($user1->id);
+        $this->assertCount(1, $contextlist);
+        $contextforuser = $contextlist->current();
+        $this->assertEquals(
+                context_user::instance($user1->id)->id,
+                $contextforuser->id);
+
+        // Test for the user receiving the contact request.
+        $contextlist = provider::get_contexts_for_userid($user2->id);
+        $this->assertCount(1, $contextlist);
+        $contextforuser = $contextlist->current();
+        $this->assertEquals(
+                context_user::instance($user2->id)->id,
+                $contextforuser->id);
+    }
+
+    /**
+     * Test for provider::get_contexts_for_userid() when a user is blocked.
+     */
+    public function test_get_contexts_for_userid_with_blocked_contact() {
+        $this->resetAfterTest();
+
+        $user1 = $this->getDataGenerator()->create_user();
+        $user2 = $this->getDataGenerator()->create_user();
+
+        // Test nothing is found before user is blocked.
+        $contextlist = provider::get_contexts_for_userid($user1->id);
+        $this->assertCount(0, $contextlist);
+        $contextlist = provider::get_contexts_for_userid($user2->id);
+        $this->assertCount(0, $contextlist);
+
+        \core_message\api::block_user($user1->id, $user2->id);
+
+        // Test for the blocking user.
+        $contextlist = provider::get_contexts_for_userid($user1->id);
+        $this->assertCount(1, $contextlist);
+        $contextforuser = $contextlist->current();
+        $this->assertEquals(
+                context_user::instance($user1->id)->id,
+                $contextforuser->id);
+
+        // Test for the user who is blocked.
+        $contextlist = provider::get_contexts_for_userid($user2->id);
         $this->assertCount(1, $contextlist);
         $contextforuser = $contextlist->current();
-        $this->assertEquals(SYSCONTEXTID, $contextforuser->id);
+        $this->assertEquals(
+                context_user::instance($user2->id)->id,
+                $contextforuser->id);
     }
 
     /**
@@ -220,9 +388,11 @@ class core_message_privacy_provider_testcase extends \core_privacy\tests\provide
         \core_message\api::add_contact($user1->id, $user3->id);
         \core_message\api::add_contact($user1->id, $user4->id);
 
-        $this->export_context_data_for_user($user1->id, \context_system::instance(), 'core_message');
+        $user1context = context_user::instance($user1->id);
 
-        $writer = writer::with_context(\context_system::instance());
+        $this->export_context_data_for_user($user1->id, $user1context, 'core_message');
+
+        $writer = writer::with_context($user1context);
 
         $contacts = (array) $writer->get_data([get_string('contacts', 'core_message')]);
         usort($contacts, ['static', 'sort_contacts']);
@@ -255,9 +425,11 @@ class core_message_privacy_provider_testcase extends \core_privacy\tests\provide
         \core_message\api::create_contact_request($user3->id, $user1->id);
         \core_message\api::create_contact_request($user1->id, $user4->id);
 
-        $this->export_context_data_for_user($user1->id, \context_system::instance(), 'core_message');
+        $user1context = context_user::instance($user1->id);
 
-        $writer = writer::with_context(\context_system::instance());
+        $this->export_context_data_for_user($user1->id, $user1context, 'core_message');
+
+        $writer = writer::with_context($user1context);
 
         $contactrequests = (array) $writer->get_data([get_string('contactrequests', 'core_message')]);
 
@@ -292,9 +464,11 @@ class core_message_privacy_provider_testcase extends \core_privacy\tests\provide
         \core_message\api::block_user($user1->id, $user3->id);
         \core_message\api::block_user($user1->id, $user4->id);
 
-        $this->export_context_data_for_user($user1->id, \context_system::instance(), 'core_message');
+        $user1context = context_user::instance($user1->id);
 
-        $writer = writer::with_context(\context_system::instance());
+        $this->export_context_data_for_user($user1->id, $user1context, 'core_message');
+
+        $writer = writer::with_context($user1context);
 
         $blockedusers = (array) $writer->get_data([get_string('blockedusers', 'core_message')]);
 
@@ -344,9 +518,11 @@ class core_message_privacy_provider_testcase extends \core_privacy\tests\provide
         \core_message\api::delete_message($user1->id, $m2);
         \core_message\api::delete_message($user1->id, $m5);
 
-        $this->export_context_data_for_user($user1->id, \context_system::instance(), 'core_message');
+        $user1context = context_user::instance($user1->id);
 
-        $writer = writer::with_context(\context_system::instance());
+        $this->export_context_data_for_user($user1->id, $user1context, 'core_message');
+
+        $writer = writer::with_context($user1context);
 
         $this->assertTrue($writer->has_any_data());
 
@@ -440,9 +616,11 @@ class core_message_privacy_provider_testcase extends \core_privacy\tests\provide
         $this->create_notification($user2->id, $user3->id, $now + (2 * DAYSECS));
         $this->create_notification($user3->id, $user2->id, $now + (1 * DAYSECS));
 
-        $this->export_context_data_for_user($user1->id, \context_system::instance(), 'core_message');
+        $user1context = context_user::instance($user1->id);
 
-        $writer = writer::with_context(\context_system::instance());
+        $this->export_context_data_for_user($user1->id, $user1context, 'core_message');
+
+        $writer = writer::with_context($user1context);
 
         $this->assertTrue($writer->has_any_data());
 
@@ -465,40 +643,153 @@ class core_message_privacy_provider_testcase extends \core_privacy\tests\provide
         $user2 = $this->getDataGenerator()->create_user();
         $user3 = $this->getDataGenerator()->create_user();
         $user4 = $this->getDataGenerator()->create_user();
+        $user5 = $this->getDataGenerator()->create_user();
 
         $now = time();
         $timeread = $now - DAYSECS;
 
-        $systemcontext = \context_system::instance();
+        $user1context = context_user::instance($user1->id);
 
         // Create contacts.
         \core_message\api::add_contact($user1->id, $user2->id);
+        \core_message\api::add_contact($user2->id, $user3->id);
 
         // Create contact requests.
         \core_message\api::create_contact_request($user1->id, $user3->id);
+        \core_message\api::create_contact_request($user2->id, $user4->id);
 
         // Block a user.
         \core_message\api::block_user($user1->id, $user3->id);
+        \core_message\api::block_user($user3->id, $user4->id);
 
         // Create messages.
         $m1 = $this->create_message($user1->id, $user2->id, $now + (9 * DAYSECS), true);
         $m2 = $this->create_message($user2->id, $user1->id, $now + (8 * DAYSECS));
+        $m3 = $this->create_message($user2->id, $user3->id, $now + (7 * DAYSECS));
 
         // Create notifications.
         $n1 = $this->create_notification($user1->id, $user2->id, $now + (9 * DAYSECS), $timeread);
         $n2 = $this->create_notification($user2->id, $user1->id, $now + (8 * DAYSECS));
+        $n3 = $this->create_notification($user2->id, $user3->id, $now + (7 * DAYSECS));
 
         // Delete one of the messages.
         \core_message\api::delete_message($user1->id, $m2);
 
-        // There should be 1 contact.
+        // There should be 2 contacts.
+        $this->assertEquals(2, $DB->count_records('message_contacts'));
+
+        // There should be 2 contact requests.
+        $this->assertEquals(2, $DB->count_records('message_contact_requests'));
+
+        // There should be 2 blocked users.
+        $this->assertEquals(2, $DB->count_records('message_users_blocked'));
+
+        // There should be 3 messages.
+        $this->assertEquals(3, $DB->count_records('messages'));
+
+        // There should be 2 user actions - one for reading the message, one for deleting.
+        $this->assertEquals(2, $DB->count_records('message_user_actions'));
+
+        // There should be 4 conversation members.
+        $this->assertEquals(4, $DB->count_records('message_conversation_members'));
+
+        // There should be 3 notifications + 2 for the contact request.
+        $this->assertEquals(5, $DB->count_records('notifications'));
+
+        provider::delete_data_for_all_users_in_context($user1context);
+
+        // Confirm there is only 1 contact left.
         $this->assertEquals(1, $DB->count_records('message_contacts'));
+        // And it is not related to user1.
+        $this->assertEquals(0,
+                $DB->count_records_select('message_contacts', 'userid = ? OR contactid = ?', [$user1->id, $user1->id]));
 
-        // There should be 1 contact request.
+        // Confirm there is only 1 contact request left.
         $this->assertEquals(1, $DB->count_records('message_contact_requests'));
+        // And it is not related to user1.
+        $this->assertEquals(0,
+                $DB->count_records_select('message_contact_requests', 'userid = ? OR requesteduserid = ?',
+                        [$user1->id, $user1->id]));
 
-        // There should be 1 blocked user.
+        // Confirm there is only 1 blocked user left.
         $this->assertEquals(1, $DB->count_records('message_users_blocked'));
+        // And it is not related to user1.
+        $this->assertEquals(0,
+                $DB->count_records_select('message_users_blocked', 'userid = ? OR blockeduserid = ?', [$user1->id, $user1->id]));
+
+        // Confirm there are only 2 messages left.
+        $this->assertEquals(2, $DB->count_records('messages'));
+        // And none of them are from user1.
+        $this->assertEquals(0, $DB->count_records('messages', ['useridfrom' => $user1->id]));
+
+        // Confirm there is only 1 user action left - the one that is for user2 reading the message.
+        $this->assertEquals(1, $DB->count_records('message_user_actions'));
+        // And it is not for user1.
+        $this->assertEquals(0, $DB->count_records('message_user_actions', ['userid' => $user1->id]));
+
+        // Confirm there are only 3 conversation members left.
+        $this->assertEquals(3, $DB->count_records('message_conversation_members'));
+        // And user1 is not in any conversation.
+        $this->assertEquals(0, $DB->count_records('message_conversation_members', ['userid' => $user1->id]));
+
+        // Confirm there is only 1 notification + 1 for the contact request.
+        $this->assertEquals(2, $DB->count_records('notifications'));
+        // And it is not related to user1.
+        $this->assertEquals(0,
+                $DB->count_records_select('notifications', 'useridfrom = ? OR useridto = ? ', [$user1->id, $user1->id]));
+    }
+
+    /**
+     * Test for provider::delete_data_for_user().
+     */
+    public function test_delete_data_for_user() {
+        global $DB;
+
+        $this->resetAfterTest();
+
+        // Create users to test with.
+        $user1 = $this->getDataGenerator()->create_user();
+        $user2 = $this->getDataGenerator()->create_user();
+        $user3 = $this->getDataGenerator()->create_user();
+        $user4 = $this->getDataGenerator()->create_user();
+        $user5 = $this->getDataGenerator()->create_user();
+        $user6 = $this->getDataGenerator()->create_user();
+
+        $now = time();
+        $timeread = $now - DAYSECS;
+
+        // Create contacts.
+        \core_message\api::add_contact($user1->id, $user2->id);
+        \core_message\api::add_contact($user2->id, $user3->id);
+
+        // Create contact requests.
+        \core_message\api::create_contact_request($user1->id, $user3->id);
+        \core_message\api::create_contact_request($user2->id, $user4->id);
+
+        // Block users.
+        \core_message\api::block_user($user1->id, $user5->id);
+        \core_message\api::block_user($user2->id, $user6->id);
+
+        // Create messages.
+        $m1 = $this->create_message($user1->id, $user2->id, $now + (9 * DAYSECS), $timeread);
+        $m2 = $this->create_message($user2->id, $user1->id, $now + (8 * DAYSECS));
+
+        // Create notifications.
+        $n1 = $this->create_notification($user1->id, $user2->id, $now + (9 * DAYSECS), $timeread);
+        $n2 = $this->create_notification($user2->id, $user1->id, $now + (8 * DAYSECS));
+        $n2 = $this->create_notification($user2->id, $user3->id, $now + (8 * DAYSECS));
+
+        // Delete one of the messages.
+        \core_message\api::delete_message($user1->id, $m2);
+
+        // There should be 2 contacts.
+        $this->assertEquals(2, $DB->count_records('message_contacts'));
+
+        // There should be 1 contact request.
+        $this->assertEquals(2, $DB->count_records('message_contact_requests'));
+
+        // There should be 1 blocked user.
+        $this->assertEquals(2, $DB->count_records('message_users_blocked'));
 
         // There should be two messages.
         $this->assertEquals(2, $DB->count_records('messages'));
@@ -509,25 +800,268 @@ class core_message_privacy_provider_testcase extends \core_privacy\tests\provide
         // There should be two conversation members.
         $this->assertEquals(2, $DB->count_records('message_conversation_members'));
 
-        // There should be two notifications + one for the contact request.
-        $this->assertEquals(3, $DB->count_records('notifications'));
+        // There should be three notifications + two for the contact requests.
+        $this->assertEquals(5, $DB->count_records('notifications'));
+
+        $user1context = context_user::instance($user1->id);
+        $contextlist = new \core_privacy\local\request\approved_contextlist($user1, 'core_message',
+            [$user1context->id]);
+        provider::delete_data_for_user($contextlist);
+
+        // Confirm the user 2 data still exists.
+        $contacts = $DB->get_records('message_contacts');
+        $contactrequests = $DB->get_records('message_contact_requests');
+        $blockedusers = $DB->get_records('message_users_blocked');
+        $messages = $DB->get_records('messages');
+        $muas = $DB->get_records('message_user_actions');
+        $mcms = $DB->get_records('message_conversation_members');
+        $notifications = $DB->get_records('notifications');
+
+        $this->assertCount(1, $contacts);
+        $contact = reset($contacts);
+        $this->assertEquals($user2->id, $contact->userid);
+        $this->assertEquals($user3->id, $contact->contactid);
+
+        $this->assertCount(1, $contactrequests);
+        $contactrequest = reset($contactrequests);
+        $this->assertEquals($user2->id, $contactrequest->userid);
+        $this->assertEquals($user4->id, $contactrequest->requesteduserid);
+
+        $this->assertCount(1, $blockedusers);
+        $blockeduser = reset($blockedusers);
+        $this->assertEquals($user2->id, $blockeduser->userid);
+        $this->assertEquals($user6->id, $blockeduser->blockeduserid);
+
+        $this->assertCount(1, $messages);
+        $message = reset($messages);
+        $this->assertEquals($m2, $message->id);
+
+        $this->assertCount(1, $muas);
+        $mua = reset($muas);
+        $this->assertEquals($user2->id, $mua->userid);
+        $this->assertEquals($m1, $mua->messageid);
+        $this->assertEquals(\core_message\api::MESSAGE_ACTION_READ, $mua->action);
+
+        $this->assertCount(1, $mcms);
+        $mcm = reset($mcms);
+        $this->assertEquals($user2->id, $mcm->userid);
+
+        $this->assertCount(2, $notifications);
+        ksort($notifications);
+
+        $notification = array_shift($notifications);
+        $this->assertEquals($user2->id, $notification->useridfrom);
+        $this->assertEquals($user4->id, $notification->useridto);
+
+        $notification = array_shift($notifications);
+        $this->assertEquals($user2->id, $notification->useridfrom);
+        $this->assertEquals($user3->id, $notification->useridto);
+    }
+
+    /**
+     * Test for provider::get_users_in_context() when there is no message or notification.
+     */
+    public function test_get_users_in_context_no_data() {
+        $this->resetAfterTest();
+
+        $user = $this->getDataGenerator()->create_user();
+        $usercontext = context_user::instance($user->id);
 
-        provider::delete_data_for_all_users_in_context($systemcontext);
+        $userlist = new \core_privacy\local\request\userlist($usercontext, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
 
-        // Confirm all has been deleted.
-        $this->assertEquals(0, $DB->count_records('message_contacts'));
-        $this->assertEquals(0, $DB->count_records('message_contact_requests'));
-        $this->assertEquals(0, $DB->count_records('message_users_blocked'));
-        $this->assertEquals(0, $DB->count_records('messages'));
-        $this->assertEquals(0, $DB->count_records('message_user_actions'));
-        $this->assertEquals(0, $DB->count_records('message_conversation_members'));
-        $this->assertEquals(0, $DB->count_records('notifications'));
+        $this->assertEmpty($userlist->get_userids());
     }
 
     /**
-     * Test for provider::delete_data_for_user().
+     * Test for provider::get_users_in_context() when there is a message between users.
      */
-    public function test_delete_data_for_user() {
+    public function test_get_users_in_context_with_message() {
+        $this->resetAfterTest();
+
+        $user1 = $this->getDataGenerator()->create_user();
+        $user2 = $this->getDataGenerator()->create_user();
+
+        $user1context = context_user::instance($user1->id);
+        $user2context = context_user::instance($user2->id);
+
+        // Test nothing is found before message is sent.
+        $userlist = new \core_privacy\local\request\userlist($user1context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(0, $userlist);
+        $userlist = new \core_privacy\local\request\userlist($user2context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(0, $userlist);
+
+        $this->create_message($user1->id, $user2->id, time() - (9 * DAYSECS));
+
+        // Test for the sender.
+        $userlist = new \core_privacy\local\request\userlist($user1context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(1, $userlist);
+        $userincontext = $userlist->current();
+        $this->assertEquals($user1->id, $userincontext->id);
+
+        // Test for the receiver.
+        $userlist = new \core_privacy\local\request\userlist($user2context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(1, $userlist);
+        $userincontext = $userlist->current();
+        $this->assertEquals($user2->id, $userincontext->id);
+    }
+
+    /**
+     * Test for provider::get_users_in_context() when there is a notification between users.
+     */
+    public function test_get_users_in_context_with_notification() {
+        $this->resetAfterTest();
+
+        $user1 = $this->getDataGenerator()->create_user();
+        $user2 = $this->getDataGenerator()->create_user();
+
+        $user1context = context_user::instance($user1->id);
+        $user2context = context_user::instance($user2->id);
+
+        // Test nothing is found before notification is created.
+        $userlist = new \core_privacy\local\request\userlist($user1context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(0, $userlist);
+        $userlist = new \core_privacy\local\request\userlist($user2context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(0, $userlist);
+
+        $this->create_notification($user1->id, $user2->id, time() - (9 * DAYSECS));
+
+        // Test for the sender.
+        $userlist = new \core_privacy\local\request\userlist($user1context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(1, $userlist);
+        $userincontext = $userlist->current();
+        $this->assertEquals($user1->id, $userincontext->id);
+
+        // Test for the receiver.
+        $userlist = new \core_privacy\local\request\userlist($user2context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(1, $userlist);
+        $userincontext = $userlist->current();
+        $this->assertEquals($user2->id, $userincontext->id);
+    }
+
+    /**
+     * Test for provider::get_users_in_context() when a users has a contact.
+     */
+    public function test_get_users_in_context_with_contact() {
+        $this->resetAfterTest();
+
+        $user1 = $this->getDataGenerator()->create_user();
+        $user2 = $this->getDataGenerator()->create_user();
+
+        $user1context = context_user::instance($user1->id);
+        $user2context = context_user::instance($user2->id);
+
+        // Test nothing is found before contact is created.
+        $userlist = new \core_privacy\local\request\userlist($user1context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(0, $userlist);
+        $userlist = new \core_privacy\local\request\userlist($user2context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(0, $userlist);
+
+        \core_message\api::add_contact($user1->id, $user2->id);
+
+        // Test for the user adding the contact.
+        $userlist = new \core_privacy\local\request\userlist($user1context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(1, $userlist);
+        $userincontext = $userlist->current();
+        $this->assertEquals($user1->id, $userincontext->id);
+
+        // Test for the user who is the contact.
+        $userlist = new \core_privacy\local\request\userlist($user2context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(1, $userlist);
+        $userincontext = $userlist->current();
+        $this->assertEquals($user2->id, $userincontext->id);
+    }
+
+    /**
+     * Test for provider::get_users_in_context() when a user makes a contact request.
+     */
+    public function test_get_users_in_context_with_contact_request() {
+        $this->resetAfterTest();
+
+        $user1 = $this->getDataGenerator()->create_user();
+        $user2 = $this->getDataGenerator()->create_user();
+
+        $user1context = context_user::instance($user1->id);
+        $user2context = context_user::instance($user2->id);
+
+        // Test nothing is found before request is created.
+        $userlist = new \core_privacy\local\request\userlist($user1context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(0, $userlist);
+        $userlist = new \core_privacy\local\request\userlist($user2context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(0, $userlist);
+
+        \core_message\api::create_contact_request($user1->id, $user2->id);
+
+        // Test for the user requesting the contact.
+        $userlist = new \core_privacy\local\request\userlist($user1context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(1, $userlist);
+        $userincontext = $userlist->current();
+        $this->assertEquals($user1->id, $userincontext->id);
+
+        // Test for the user receiving the contact request.
+        $userlist = new \core_privacy\local\request\userlist($user2context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(1, $userlist);
+        $userincontext = $userlist->current();
+        $this->assertEquals($user2->id, $userincontext->id);
+    }
+
+    /**
+     * Test for provider::get_users_in_context() when a user is blocked.
+     */
+    public function test_get_users_in_context_with_blocked_contact() {
+        $this->resetAfterTest();
+
+        $user1 = $this->getDataGenerator()->create_user();
+        $user2 = $this->getDataGenerator()->create_user();
+
+        $user1context = context_user::instance($user1->id);
+        $user2context = context_user::instance($user2->id);
+
+        // Test nothing is found before user is blocked.
+        $userlist = new \core_privacy\local\request\userlist($user1context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(0, $userlist);
+        $userlist = new \core_privacy\local\request\userlist($user2context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(0, $userlist);
+
+        \core_message\api::block_user($user1->id, $user2->id);
+
+        // Test for the blocking user.
+        $userlist = new \core_privacy\local\request\userlist($user1context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(1, $userlist);
+        $userincontext = $userlist->current();
+        $this->assertEquals($user1->id, $userincontext->id);
+
+        // Test for the user who is blocked.
+        $userlist = new \core_privacy\local\request\userlist($user2context, 'core_message');
+        \core_message\privacy\provider::get_users_in_context($userlist);
+        $this->assertCount(1, $userlist);
+        $userincontext = $userlist->current();
+        $this->assertEquals($user2->id, $userincontext->id);
+    }
+
+    /**
+     * Test for provider::delete_data_for_users().
+     */
+    public function test_delete_data_for_users() {
         global $DB;
 
         $this->resetAfterTest();
@@ -588,10 +1122,12 @@ class core_message_privacy_provider_testcase extends \core_privacy\tests\provide
         // There should be three notifications + two for the contact requests.
         $this->assertEquals(5, $DB->count_records('notifications'));
 
-        $systemcontext = \context_system::instance();
-        $contextlist = new \core_privacy\local\request\approved_contextlist($user1, 'core_message',
-            [$systemcontext->id]);
-        provider::delete_data_for_user($contextlist);
+        $user1context = context_user::instance($user1->id);
+        $approveduserlist = new \core_privacy\local\request\approved_userlist($user1context, 'core_message',
+                [$user1->id, $user2->id]);
+        provider::delete_data_for_users($approveduserlist);
+
+        // Only user1's data should be deleted. User2 should be skipped as user2 is an invalid user for user1context.
 
         // Confirm the user 2 data still exists.
         $contacts = $DB->get_records('message_contacts');