MDL-61672 admin: Fix sitepolicy handler API

The base class had abstract static methods which raises strict standards
warning on PHP 5.6.

privacy/classes/local/sitepolicy/handler.php

@@ -24,6 +24,8 @@
 
 namespace core_privacy\local\sitepolicy;
 
+use coding_exception;
+
 defined('MOODLE_INTERNAL') || die();
 
 /**
@@ -54,10 +56,14 @@ abstract class handler {
      * This is a regular interactive page for web users. It should have normal Moodle header/footers, it should
      * allow user to view policies and accept them.
      *
+     * This would normally be an abstract static method but PHP 5.6 raises strict standards warning for such ones.
+     *
      * @param bool $forguests
      * @return moodle_url|null (returns null if site policy is not defined)
      */
-    abstract public static function get_redirect_url($forguests = false);
+    public static function get_redirect_url($forguests = false) {
+        throw new coding_exception('Method get_redirect_url() not implemented by the handler');
+    }
 
     /**
      * Returns URL of the site policy that needs to be displayed to the user (inside iframe or to use in WS such as mobile app)
@@ -65,10 +71,14 @@ abstract class handler {
      * This page should not have any header/footer, it does not also have any buttons/checkboxes. The caller needs to implement
      * the "Accept" button and call {@link self::accept()} on completion.
      *
+     * This would normally be an abstract static method but PHP 5.6 raises strict standards warning for such ones.
+     *
      * @param bool $forguests
      * @return moodle_url|null
      */
-    abstract public static function get_embed_url($forguests = false);
+    public static function get_embed_url($forguests = false) {
+        throw new coding_exception('Method get_embed_url() not implemented by the handler');
+    }
 
     /**
      * Accept site policy for the current user

privacy/tests/fixtures/mock_incomplete_sitepolicy_handler.php

@@ -0,0 +1,48 @@
+<?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/>.
+
+/**
+ * Provides {@link mock_incomplete_sitepolicy_handler} class.
+ *
+ * @package     core_privacy
+ * @category    test
+ * @copyright   2018 David Mudrák <[email protected]>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Incomplete mock handler for site policies not implementing all required methods.
+ *
+ * Particularly, get_embed_url() is missing.
+ *
+ * @package     core_privacy
+ * @copyright   2018 David Mudrák <[email protected]>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class mock_incomplete_sitepolicy_handler extends \core_privacy\local\sitepolicy\handler {
+
+    /**
+     * Returns URL to redirect user to when user needs to agree to site policy
+     *
+     * @param bool $forguests
+     * @return moodle_url|string|null
+     */
+    public static function get_redirect_url($forguests = false) {
+        return 'http://example.com/policy.php';
+    }
+}

privacy/tests/sitepolicy_test.php

@@ -259,6 +259,32 @@ class sitepolicy_test extends advanced_testcase {
         $this->assertEquals(2, $USER->policyagreed);
         $this->assertEquals(0, $DB->get_field('user', 'policyagreed', ['id' => $USER->id]));
     }
+
+    /**
+     * Test behaviour of \core_privacy\local\sitepolicy\manager with a handler not implementing all required methods.
+     */
+    public function test_incomplete_handler() {
+        global $CFG;
+        require_once($CFG->dirroot.'/privacy/tests/fixtures/mock_incomplete_sitepolicy_handler.php');
+        $this->resetAfterTest(true);
+
+        $CFG->sitepolicyhandler = 'testtool_incompletehandler';
+
+        $manager = $this->getMockBuilder(\core_privacy\local\sitepolicy\manager::class)
+            ->setMethods(['get_all_handlers'])
+            ->getMock();
+        $manager->expects($this->any())
+            ->method('get_all_handlers')
+            ->will($this->returnValue(['testtool_incompletehandler' => 'mock_incomplete_sitepolicy_handler']));
+
+        // This works because the handler implements get_redirect_url().
+        $this->assertEquals('http://example.com/policy.php', $manager->get_redirect_url()->out());
+
+        // This must inform them developer that the handler does not implement a method.
+        $this->expectException('coding_exception');
+        $this->expectExceptionMessage('Method get_embed_url() not implemented by the handler');
+        $manager->get_embed_url();
+    }
 }
 
 /**