<?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/>.

/**
 * Weblib tests.
 *
 * @package    core
 * @category   phpunit
 * @copyright  &copy; 2006 The Open University
 * @author     T.J.Hunt@open.ac.uk
 * @license    http://www.gnu.org/copyleft/gpl.html GNU Public License
 */

< 
< defined('MOODLE_INTERNAL') || die();
< 
< 
< class core_weblib_testcase extends advanced_testcase {
< 



> class weblib_test extends advanced_testcase {
>     /**
>      * @covers ::format_string
>      */


    public function test_format_string() {
        global $CFG;

        // Ampersands.
        $this->assertSame("&amp; &amp;&amp;&amp;&amp;&amp; &amp;&amp;", format_string("& &&&&& &&"));
        $this->assertSame("ANother &amp; &amp;&amp;&amp;&amp;&amp; Category", format_string("ANother & &&&&& Category"));
        $this->assertSame("ANother &amp; &amp;&amp;&amp;&amp;&amp; Category", format_string("ANother & &&&&& Category", true));
        $this->assertSame("Nick's Test Site &amp; Other things", format_string("Nick's Test Site & Other things", true));
        $this->assertSame("& < > \" '", format_string("& < > \" '", true, ['escape' => false]));

        // String entities.
        $this->assertSame("&quot;", format_string("&quot;"));

        // Digital entities.
        $this->assertSame("&11234;", format_string("&11234;"));

        // Unicode entities.
        $this->assertSame("&#4475;", format_string("&#4475;"));


>         // Nulls.
        // < and > signs.
>         $this->assertSame('', format_string(null));
        $originalformatstringstriptags = $CFG->formatstringstriptags;
>         $this->assertSame('', format_string(null, true, ['escape' => false]));

> 


        $CFG->formatstringstriptags = false;
        $this->assertSame('x &lt; 1', format_string('x < 1'));
        $this->assertSame('x &gt; 1', format_string('x > 1'));
        $this->assertSame('x &lt; 1 and x &gt; 0', format_string('x < 1 and x > 0'));

        $CFG->formatstringstriptags = true;
        $this->assertSame('x &lt; 1', format_string('x < 1'));
        $this->assertSame('x &gt; 1', format_string('x > 1'));
        $this->assertSame('x &lt; 1 and x &gt; 0', format_string('x < 1 and x > 0'));

        $CFG->formatstringstriptags = $originalformatstringstriptags;
    }

    /**
     * The format string static caching should include the filters option to make
     * sure filters are correctly applied when requested.
     */
    public function test_format_string_static_caching_with_filters() {
        global $CFG;

        $this->resetAfterTest(true);
        $this->setAdminUser();
        $generator = $this->getDataGenerator();
        $course = $generator->create_course();
        $user = $generator->create_user();

<         $rawstring = 'Shortname <a href="#">link</a> curseword';
<         $expectednofilter = strip_links($rawstring);
<         $expectedfilter = 'Shortname link \*\**';



>         $rawstring = '<span lang="en" class="multilang">English</span><span lang="ca" class="multilang">Catalan</span>';
>         $expectednofilter = strip_tags($rawstring);
>         $expectedfilter = 'English';


        $striplinks = true;
        $context = context_course::instance($course->id);
        $options = [
            'context' => $context,
            'escape' => true,
            'filter' => false
        ];

        $this->setUser($user);

        // Format the string without filters. It should just strip the
        // links.
        $nofilterresult = format_string($rawstring, $striplinks, $options);
        $this->assertEquals($expectednofilter, $nofilterresult);


<         // Add the censor filter. Make sure it's enabled globally.



>         // Add the multilang filter. Make sure it's enabled globally.


        $CFG->filterall = true;

<         $CFG->stringfilters = 'censor';
<         $CFG->filter_censor_badwords = 'curseword';
<         filter_set_global_state('censor', TEXTFILTER_ON);
<         filter_set_local_state('censor', $context->id, TEXTFILTER_ON);



>         $CFG->stringfilters = 'multilang';
>         filter_set_global_state('multilang', TEXTFILTER_ON);
>         filter_set_local_state('multilang', $context->id, TEXTFILTER_ON);


        // This time we want to apply the filters.
        $options['filter'] = true;
        $filterresult = format_string($rawstring, $striplinks, $options);
        $this->assertMatchesRegularExpression("/$expectedfilter/", $filterresult);


<         filter_set_local_state('censor', $context->id, TEXTFILTER_OFF);



>         filter_set_local_state('multilang', $context->id, TEXTFILTER_OFF);



        // Confirm that we get back the cached string. The result should be
        // the same as the filtered text above even though we've disabled the

<         // censor filter in between.



>         // multilang filter in between.


        $cachedresult = format_string($rawstring, $striplinks, $options);
        $this->assertMatchesRegularExpression("/$expectedfilter/", $cachedresult);
    }


>     /**
    public function test_s() {
>      * @covers ::s
        // Special cases.
>      */


        $this->assertSame('0', s(0));
        $this->assertSame('0', s('0'));
        $this->assertSame('0', s(false));
        $this->assertSame('', s(null));

        // Normal cases.
        $this->assertSame('This Breaks &quot; Strict', s('This Breaks " Strict'));
        $this->assertSame('This Breaks &lt;a&gt;&quot; Strict&lt;/a&gt;', s('This Breaks <a>" Strict</a>'));

        // Unicode characters.
        $this->assertSame('Café', s('Café'));
        $this->assertSame('一, 二, 三', s('一, 二, 三'));

        // Don't escape already-escaped numeric entities. (Note, this behaviour
        // may not be desirable. Perhaps we should remove these tests and that
        // functionality, but we can only do that if we understand why it was added.)
        $this->assertSame('An entity: &#x09ff;.', s('An entity: &#x09ff;.'));
        $this->assertSame('An entity: &#1073;.', s('An entity: &#1073;.'));
        $this->assertSame('An entity: &amp;amp;.', s('An entity: &amp;.'));
        $this->assertSame('Not an entity: &amp;amp;#x09ff;.', s('Not an entity: &amp;#x09ff;.'));

        // Test all ASCII characters (0-127).
        for ($i = 0; $i <= 127; $i++) {
            $character = chr($i);
            $result = s($character);
            switch ($character) {
                case '"' :
                    $this->assertSame('&quot;', $result);
                    break;
                case '&' :
                    $this->assertSame('&amp;', $result);
                    break;
                case "'" :
                    $this->assertSame('&#039;', $result);
                    break;
                case '<' :
                    $this->assertSame('&lt;', $result);
                    break;
                case '>' :
                    $this->assertSame('&gt;', $result);
                    break;
                default:
                    $this->assertSame($character, $result);
                    break;
            }
        }
    }


>     /**
    public function test_format_text_email() {
>      * Test the format_string illegal options handling.
        $this->assertSame("This is a TEST\n",
>      *
            format_text_email('<p>This is a <strong>test</strong></p>', FORMAT_HTML));
>      * @covers ::format_string
        $this->assertSame("This is a TEST\n",
>      * @dataProvider format_string_illegal_options_provider
            format_text_email('<p class="frogs">This is a <strong class=\'fishes\'>test</strong></p>', FORMAT_HTML));
>      */
        $this->assertSame('& so is this',
>     public function test_format_string_illegal_options(
            format_text_email('&amp; so is this', FORMAT_HTML));
>         string $input,
        $this->assertSame('Two bullets: ' . core_text::code2utf8(8226) . ' ' . core_text::code2utf8(8226),
>         string $result,
            format_text_email('Two bullets: &#x2022; &#8226;', FORMAT_HTML));
>         $options,
        $this->assertSame(core_text::code2utf8(0x7fd2).core_text::code2utf8(0x7fd2),
>         string $pattern
            format_text_email('&#x7fd2;&#x7FD2;', FORMAT_HTML));
>     ): void {
    }
>         $this->assertEquals(

>             $result,
    public function test_obfuscate_email() {
>             format_string($input, false, $options)
        $email = 'some.user@example.com';
>         );
        $obfuscated = obfuscate_email($email);
> 
        $this->assertNotSame($email, $obfuscated);
>         $messages = $this->getDebuggingMessages();
        $back = core_text::entities_to_utf8(urldecode($email), true);
>         $this->assertdebuggingcalledcount(1);
        $this->assertSame($email, $back);
>         $this->assertMatchesRegularExpression(
    }
>             "/{$pattern}/",

>             $messages[0]->message
    public function test_obfuscate_text() {
>         );
        $text = 'Žluťoučký koníček 32131';
>     }
        $obfuscated = obfuscate_text($text);
> 
        $this->assertNotSame($text, $obfuscated);
>     /**
        $back = core_text::entities_to_utf8($obfuscated, true);
>      * Data provider for test_format_string_illegal_options.
        $this->assertSame($text, $back);
>      * @return array
    }
>      */

>     public static function format_string_illegal_options_provider(): array {
    public function test_highlight() {
>         return [
        $this->assertSame('This is <span class="highlight">good</span>',
>             [
                highlight('good', 'This is good'));
>                 'Example',

>                 'Example',
        $this->assertSame('<span class="highlight">span</span>',
>                 \context_system::instance(),
                highlight('SpaN', 'span'));
>                 preg_quote('The options argument should not be a context object directly.'),

>             ],
        $this->assertSame('<span class="highlight">SpaN</span>',
>             [
                highlight('span', 'SpaN'));
>                 'Example',

>                 'Example',
        $this->assertSame('<span><span class="highlight">span</span></span>',
>                 true,
                highlight('span', '<span>span</span>'));
>                 preg_quote('The options argument should be an Array, or stdclass. boolean passed.'),

>             ],
        $this->assertSame('He <span class="highlight">is</span> <span class="highlight">good</span>',
>             [
                highlight('good is', 'He is good'));
>                 'Example',

>                 'Example',
        $this->assertSame('This is <span class="highlight">good</span>',
>                 false,
                highlight('+good', 'This is good'));
>                 preg_quote('The options argument should be an Array, or stdclass. boolean passed.'),

>             ],
        $this->assertSame('This is good',
>         ];
                highlight('-good', 'This is good'));
>     }

> 
        $this->assertSame('This is goodness',
>     /**
                highlight('+good', 'This is goodness'));
>      * Ensure that if format_string is called with a context as the third param, that a debugging notice is emitted.

>      *
        $this->assertSame('This is <span class="highlight">good</span>ness',
>      * @covers ::format_string
                highlight('good', 'This is goodness'));
>      */

>     public function test_format_string_context(): void {
        $this->assertSame('<p><b>test</b> <b>1</b></p><p><b>1</b></p>',
>         global $CFG;
                highlight('test 1', '<p>test 1</p><p>1</p>', false, '<b>', '</b>'));
> 

>         $this->resetAfterTest(true);
        $this->assertSame('<p><b>test</b> <b>1</b></p><p><b>1</b></p>',
> 
                    highlight('test +1', '<p>test 1</p><p>1</p>', false, '<b>', '</b>'));
>         // Disable the formatstringstriptags option to ensure that the HTML tags are not stripped.

>         $CFG->stringfilters = 'multilang';
        $this->assertSame('<p><b>test</b> 1</p><p>1</p>',
> 
                    highlight('test -1', '<p>test 1</p><p>1</p>', false, '<b>', '</b>'));
>         // Enable filters.
    }
>         $CFG->filterall = true;

> 
    public function test_replace_ampersands() {
>         $course = $this->getDataGenerator()->create_course();
        $this->assertSame("This &amp; that &nbsp;", replace_ampersands_not_followed_by_entity("This & that &nbsp;"));
>         $coursecontext = \context_course::instance($course->id);
        $this->assertSame("This &amp;nbsp that &nbsp;", replace_ampersands_not_followed_by_entity("This &nbsp that &nbsp;"));
> 
    }
>         // Set up the multilang filter at the system context, but disable it at the course.

>         filter_set_global_state('multilang', TEXTFILTER_ON);
    public function test_strip_links() {
>         filter_set_local_state('multilang', $coursecontext->id, TEXTFILTER_OFF);
        $this->assertSame('this is a link', strip_links('this is a <a href="http://someaddress.com/query">link</a>'));
> 
    }
>         // Previously, if a context was passed, it was converted into an Array, and ignored.

>         // The PAGE context was used instead -- often this is the system context.
    public function test_wikify_links() {
>         $input = 'I really <span lang="en" class="multilang">do not </span><span lang="de" class="multilang">do not </span>like this!';
        $this->assertSame('this is a link [ http://someaddress.com/query ]', wikify_links('this is a <a href="http://someaddress.com/query">link</a>'));
> 
    }
>         $result = format_string(

>             $input,
    public function test_clean_text() {
>             true,
        $text = "lala <applet>xx</applet>";
>             $coursecontext
        $this->assertSame($text, clean_text($text, FORMAT_PLAIN));
>         );
        $this->assertSame('lala xx', clean_text($text, FORMAT_MARKDOWN));
> 
        $this->assertSame('lala xx', clean_text($text, FORMAT_MOODLE));
>         // We emit a debugging notice to alert that the context has been moved to the options.
        $this->assertSame('lala xx', clean_text($text, FORMAT_HTML));
>         $this->assertdebuggingcalledcount(1);
    }
> 

>         // Check the result was _not_ filtered.
    public function test_qualified_me() {
>         $this->assertEquals(
        global $PAGE, $FULLME, $CFG;
>             // Tags are stripped out due to striptags.
        $this->resetAfterTest();
>             "I really do not do not like this!",

>             $result
        $PAGE = new moodle_page();
>         );

> 
        $FULLME = $CFG->wwwroot.'/course/view.php?id=1&xx=yy';
>         // But it should be filtered if called with the system context.
        $this->assertSame($FULLME, qualified_me());
>         $result = format_string(

>             $input,
        $PAGE->set_url('/course/view.php', array('id'=>1));
>             true,
        $this->assertSame($CFG->wwwroot.'/course/view.php?id=1', qualified_me());
>             ['context' => \context_system::instance()],
    }
>         );

>         $this->assertEquals(
    public function test_null_progres_trace() {
>             'I really do not like this!',
        $this->resetAfterTest(false);
>             $result

>         );
        $trace = new null_progress_trace();
>     }
        $trace->output('do');
> 
        $trace->output('re', 1);
>     /**
        $trace->output('mi', 2);
>      * @covers ::format_text_email
        $trace->finished();
>      */


        $output = ob_get_contents();

>     /**
        $this->assertSame('', $output);
>      * @covers ::obfuscate_email
        $this->expectOutputString('');
>      */


    }

>     /**

>      * @covers ::obfuscate_text
    public function test_text_progres_trace() {
>      */


        $this->resetAfterTest(false);

>     /**

>      * @covers ::highlight
        $trace = new text_progress_trace();
>      */


        $trace->output('do');

>     /**
        $trace->output('re', 1);
>      * @covers ::replace_ampersands_not_followed_by_entity
        $trace->output('mi', 2);
>      */


        $trace->finished();

>     /**
        $this->expectOutputString("do\n  re\n    mi\n");
>      * @covers ::strip_links
    }
>      */




>     /**
    public function test_html_progres_trace() {
>      * @covers ::wikify_links
        $this->resetAfterTest(false);
>      */




>     /**
        $trace = new html_progress_trace();
>      * @covers ::clean_text
        $trace->output('do');
>      */


        $trace->output('re', 1);

>     /**
        $trace->output('mi', 2);
>      * Test trusttext enabling.
        $trace->finished();
>      *
        $this->expectOutputString("<p>do</p>\n<p>&#160;&#160;re</p>\n<p>&#160;&#160;&#160;&#160;mi</p>\n");
>      * @covers ::trusttext_active
    }
>      */

>     public function test_trusttext_active() {
    public function test_html_list_progress_trace() {
>         global $CFG;
        $this->resetAfterTest(false);
>         $this->resetAfterTest();

> 
        $trace = new html_list_progress_trace();
>         $this->assertFalse(trusttext_active());
        $trace->output('do');
>         $CFG->enabletrusttext = '1';
        $trace->output('re', 1);
>         $this->assertTrue(trusttext_active());
        $trace->output('mi', 2);
>     }
        $trace->finished();
> 
        $this->expectOutputString("<ul>\n<li>do<ul>\n<li>re<ul>\n<li>mi</li>\n</ul>\n</li>\n</ul>\n</li>\n</ul>\n");
>     /**
    }
>      * Test trusttext detection.

>      *
    public function test_progres_trace_buffer() {
>      * @covers ::trusttext_trusted
        $this->resetAfterTest(false);
>      */

>     public function test_trusttext_trusted() {
        $trace = new progress_trace_buffer(new html_progress_trace());
>         global $CFG;
        ob_start();
>         $this->resetAfterTest();
        $trace->output('do');
> 
        $trace->output('re', 1);
>         $syscontext = context_system::instance();
        $trace->output('mi', 2);
>         $course = $this->getDataGenerator()->create_course();
        $trace->finished();
>         $coursecontext = context_course::instance($course->id);
        $output = ob_get_contents();
>         $user1 = $this->getDataGenerator()->create_user();
        ob_end_clean();
>         $user2 = $this->getDataGenerator()->create_user();
        $this->assertSame("<p>do</p>\n<p>&#160;&#160;re</p>\n<p>&#160;&#160;&#160;&#160;mi</p>\n", $output);
>         $this->getDataGenerator()->enrol_user($user2->id, $course->id, 'editingteacher');
        $this->assertSame($output, $trace->get_buffer());
> 

>         $this->setAdminUser();
        $trace = new progress_trace_buffer(new html_progress_trace(), false);
> 
        $trace->output('do');
>         $CFG->enabletrusttext = '0';
        $trace->output('re', 1);
>         $this->assertFalse(trusttext_trusted($syscontext));
        $trace->output('mi', 2);
>         $this->assertFalse(trusttext_trusted($coursecontext));
        $trace->finished();
> 
        $this->assertSame("<p>do</p>\n<p>&#160;&#160;re</p>\n<p>&#160;&#160;&#160;&#160;mi</p>\n", $trace->get_buffer());
>         $CFG->enabletrusttext = '1';
        $this->assertSame("<p>do</p>\n<p>&#160;&#160;re</p>\n<p>&#160;&#160;&#160;&#160;mi</p>\n", $trace->get_buffer());
>         $this->assertTrue(trusttext_trusted($syscontext));
        $trace->reset_buffer();
>         $this->assertTrue(trusttext_trusted($coursecontext));
        $this->assertSame('', $trace->get_buffer());
> 
        $this->expectOutputString('');
>         $this->setUser($user1);
    }
> 

>         $CFG->enabletrusttext = '0';
    public function test_combined_progres_trace() {
>         $this->assertFalse(trusttext_trusted($syscontext));
        $this->resetAfterTest(false);
>         $this->assertFalse(trusttext_trusted($coursecontext));

> 
        $trace1 = new progress_trace_buffer(new html_progress_trace(), false);
>         $CFG->enabletrusttext = '1';
        $trace2 = new progress_trace_buffer(new text_progress_trace(), false);
>         $this->assertFalse(trusttext_trusted($syscontext));

>         $this->assertFalse(trusttext_trusted($coursecontext));
        $trace = new combined_progress_trace(array($trace1, $trace2));
> 
        $trace->output('do');
>         $this->setUser($user2);
        $trace->output('re', 1);
> 
        $trace->output('mi', 2);
>         $CFG->enabletrusttext = '0';
        $trace->finished();
>         $this->assertFalse(trusttext_trusted($syscontext));
        $this->assertSame("<p>do</p>\n<p>&#160;&#160;re</p>\n<p>&#160;&#160;&#160;&#160;mi</p>\n", $trace1->get_buffer());
>         $this->assertFalse(trusttext_trusted($coursecontext));
        $this->assertSame("do\n  re\n    mi\n", $trace2->get_buffer());
> 
        $this->expectOutputString('');
>         $CFG->enabletrusttext = '1';
    }
>         $this->assertFalse(trusttext_trusted($syscontext));

>         $this->assertTrue(trusttext_trusted($coursecontext));
    public function test_set_debugging() {
>     }
        global $CFG;
> 

>     /**
        $this->resetAfterTest();
>      * Data provider for trusttext_pre_edit() tests.

>      */
        $this->assertEquals(DEBUG_DEVELOPER, $CFG->debug);
>     public function trusttext_pre_edit_provider(): array {
        $this->assertTrue($CFG->debugdeveloper);
>         return [
        $this->assertNotEmpty($CFG->debugdisplay);
>             [true, 0, 'editingteacher', FORMAT_HTML, 1],

>             [true, 0, 'editingteacher', FORMAT_MOODLE, 1],
        set_debugging(DEBUG_DEVELOPER, true);
>             [false, 0, 'editingteacher', FORMAT_MARKDOWN, 1],
        $this->assertEquals(DEBUG_DEVELOPER, $CFG->debug);
>             [false, 0, 'editingteacher', FORMAT_PLAIN, 1],
        $this->assertTrue($CFG->debugdeveloper);
> 
        $this->assertNotEmpty($CFG->debugdisplay);
>             [false, 1, 'editingteacher', FORMAT_HTML, 1],

>             [false, 1, 'editingteacher', FORMAT_MOODLE, 1],
        set_debugging(DEBUG_DEVELOPER, false);
>             [false, 1, 'editingteacher', FORMAT_MARKDOWN, 1],
        $this->assertEquals(DEBUG_DEVELOPER, $CFG->debug);
>             [false, 1, 'editingteacher', FORMAT_PLAIN, 1],
        $this->assertTrue($CFG->debugdeveloper);
> 
        $this->assertEmpty($CFG->debugdisplay);
>             [true, 0, 'student', FORMAT_HTML, 1],

>             [true, 0, 'student', FORMAT_MOODLE, 1],
        set_debugging(-1);
>             [false, 0, 'student', FORMAT_MARKDOWN, 1],
        $this->assertEquals(-1, $CFG->debug);
>             [false, 0, 'student', FORMAT_PLAIN, 1],
        $this->assertTrue($CFG->debugdeveloper);
> 

>             [true, 1, 'student', FORMAT_HTML, 1],
        set_debugging(DEBUG_ALL);
>             [true, 1, 'student', FORMAT_MOODLE, 1],
        $this->assertEquals(DEBUG_ALL, $CFG->debug);
>             [false, 1, 'student', FORMAT_MARKDOWN, 1],
        $this->assertFalse($CFG->debugdeveloper);
>             [false, 1, 'student', FORMAT_PLAIN, 1],

>         ];
        set_debugging(DEBUG_NORMAL);
>     }
        $this->assertEquals(DEBUG_NORMAL, $CFG->debug);
> 
        $this->assertFalse($CFG->debugdeveloper);
>     /**

>      * Test text cleaning before editing.
        set_debugging(DEBUG_MINIMAL);
>      *
        $this->assertEquals(DEBUG_MINIMAL, $CFG->debug);
>      * @dataProvider trusttext_pre_edit_provider
        $this->assertFalse($CFG->debugdeveloper);
>      * @covers ::trusttext_pre_edit

>      *
        set_debugging(DEBUG_NONE);
>      * @param bool $expectedsanitised
        $this->assertEquals(DEBUG_NONE, $CFG->debug);
>      * @param int $enabled
        $this->assertFalse($CFG->debugdeveloper);
>      * @param string $rolename
    }
>      * @param string $format

>      * @param int $trust
    public function test_strip_pluginfile_content() {
>      */
        $source = <<<SOURCE
>     public function test_trusttext_pre_edit(bool $expectedsanitised, int $enabled, string $rolename,
Hello!
>                                             string $format, int $trust) {

>         global $CFG, $DB;
I'm writing to you from the Moodle Majlis in Muscat, Oman, where we just had several days of Moodle community goodness.
>         $this->resetAfterTest();

> 
URL outside a tag: https://moodle.org/logo/logo-240x60.gif
>         $exploit = "abc<script>alert('xss')</script> < > &";
Plugin url outside a tag: @@PLUGINFILE@@/logo-240x60.gif
>         $sanitised = purify_html($exploit);

> 
External link 1:<img src='https://moodle.org/logo/logo-240x60.gif' alt='Moodle'/>
>         $course = $this->getDataGenerator()->create_course();
External link 2:<img alt="Moodle" src="https://moodle.org/logo/logo-240x60.gif"/>
>         $context = context_course::instance($course->id);
Internal link 1:<img src='@@PLUGINFILE@@/logo-240x60.gif' alt='Moodle'/>
> 
Internal link 2:<img alt="Moodle" src="@@PLUGINFILE@@logo-240x60.gif"/>
>         $user = $this->getDataGenerator()->create_user();
Anchor link 1:<a href="@@PLUGINFILE@@logo-240x60.gif" alt="bananas">Link text</a>
>         $this->getDataGenerator()->enrol_user($user->id, $course->id, $rolename);
Anchor link 2:<a title="bananas" href="../logo-240x60.gif">Link text</a>
> 
Anchor + ext. img:<a title="bananas" href="../logo-240x60.gif"><img alt="Moodle" src="@@PLUGINFILE@@logo-240x60.gif"/></a>
>         $this->setUser($user);
Ext. anchor + img:<a href="@@PLUGINFILE@@logo-240x60.gif"><img alt="Moodle" src="https://moodle.org/logo/logo-240x60.gif"/></a>
> 
SOURCE;
>         $CFG->enabletrusttext = (string)$enabled;
        $expected = <<<EXPECTED
> 
Hello!
>         $object = new stdClass();

>         $object->some = $exploit;
I'm writing to you from the Moodle Majlis in Muscat, Oman, where we just had several days of Moodle community goodness.
>         $object->someformat = $format;

>         $object->sometrust = (string)$trust;
URL outside a tag: https://moodle.org/logo/logo-240x60.gif
>         $result = trusttext_pre_edit(clone($object), 'some', $context);
Plugin url outside a tag: @@PLUGINFILE@@/logo-240x60.gif
> 

>         if ($expectedsanitised) {
External link 1:<img src="https://moodle.org/logo/logo-240x60.gif" alt="Moodle" />
>             $message = "sanitisation is expected for: $enabled, $rolename, $format, $trust";
External link 2:<img alt="Moodle" src="https://moodle.org/logo/logo-240x60.gif" />
>             $this->assertSame($sanitised, $result->some, $message);
Internal link 1:
>         } else {
Internal link 2:
>             $message = "sanitisation is not expected for: $enabled, $rolename, $format, $trust";
Anchor link 1:Link text
>             $this->assertSame($exploit, $result->some, $message);
Anchor link 2:<a title="bananas" href="../logo-240x60.gif">Link text</a>
>         }
Anchor + ext. img:<a title="bananas" href="../logo-240x60.gif"></a>
>     }
Ext. anchor + img:<img alt="Moodle" src="https://moodle.org/logo/logo-240x60.gif" />
> 
EXPECTED;
>     /**
        $this->assertSame($expected, strip_pluginfile_content($source));
>      * Test removal of legacy trusttext flag.
    }
>      * @covers ::trusttext_strip

>      */
    public function test_purify_html_ruby() {
>     public function test_trusttext_strip() {

>         $this->assertSame('abc', trusttext_strip('abc'));
        $this->resetAfterTest();
>         $this->assertSame('abc', trusttext_strip('ab#####TRUSTTEXT#####c'));

>     }
        $ruby =
> 
            "<p><ruby><rb>京都</rb><rp>(</rp><rt>きょうと</rt><rp>)</rp></ruby>は" .
>     /**
            "<ruby><rb>日本</rb><rp>(</rp><rt>にほん</rt><rp>)</rp></ruby>の" .
>      * Test trust option of format_text().
            "<ruby><rb>都</rb><rp>(</rp><rt>みやこ</rt><rp>)</rp></ruby>です。</p>";
>      * @covers ::format_text
        $illegal = '<script src="//code.jquery.com/jquery-1.11.3.min.js"></script>';
>      */

>     public function test_format_text_trusted() {
        $cleaned = purify_html($ruby . $illegal);
>         global $CFG;
        $this->assertEquals($ruby, $cleaned);
>         $this->resetAfterTest();

> 
    }
>         $text = "lala <object>xx</object>";

> 
    /**
>         $CFG->enabletrusttext = 0;
     * Tests for content_to_text.
> 
     *
>         $this->assertSame(s($text),
     * @param string    $content   The content
>             format_text($text, FORMAT_PLAIN, ['trusted' => true]));
     * @param int|false $format    The content format
>         $this->assertSame("<p>lala xx</p>\n",
     * @param string    $expected  Expected value
>             format_text($text, FORMAT_MARKDOWN, ['trusted' => true]));
     * @dataProvider provider_content_to_text
>         $this->assertSame('<div class="text_to_html">lala xx</div>',
     */
>             format_text($text, FORMAT_MOODLE, ['trusted' => true]));
    public function test_content_to_text($content, $format, $expected) {
>         $this->assertSame('lala xx',
        $content = content_to_text($content, $format);
>             format_text($text, FORMAT_HTML, ['trusted' => true]));
        $this->assertEquals($expected, $content);
> 
    }
>         $this->assertSame(s($text),

>             format_text($text, FORMAT_PLAIN, ['trusted' => false]));
    /**
>         $this->assertSame("<p>lala xx</p>\n",
     * Data provider for test_content_to_text.
>             format_text($text, FORMAT_MARKDOWN, ['trusted' => false]));
     */
>         $this->assertSame('<div class="text_to_html">lala xx</div>',
    public static function provider_content_to_text() {
>             format_text($text, FORMAT_MOODLE, ['trusted' => false]));
        return array(
>         $this->assertSame('lala xx',
            array('asd', false, 'asd'),
>             format_text($text, FORMAT_HTML, ['trusted' => false]));
            // Trim '\r\n '.
> 
            array("Note that:\n\n3 > 1 ", FORMAT_PLAIN, "Note that:\n\n3 > 1"),
>         $CFG->enabletrusttext = 1;
            array("Note that:\n\n3 > 1\r\n", FORMAT_PLAIN, "Note that:\n\n3 > 1"),
> 
            // Multiple spaces to one.
>         $this->assertSame(s($text),
            array('<span class="eheh">京都</span>  ->  hehe', FORMAT_HTML, '京都 -> hehe'),
>             format_text($text, FORMAT_PLAIN, ['trusted' => true]));
            array('<span class="eheh">京都</span>  ->  hehe', false, '京都 -> hehe'),
>         $this->assertSame("<p>lala xx</p>\n",
            array('asd    asd', false, 'asd asd'),
>             format_text($text, FORMAT_MARKDOWN, ['trusted' => true]));
            // From markdown to html and html to text.
>         $this->assertSame('<div class="text_to_html">lala <object>xx</object></div>',
            array('asd __lera__ con la', FORMAT_MARKDOWN, 'asd LERA con la'),
>             format_text($text, FORMAT_MOODLE, ['trusted' => true]));
            // HTML to text.
>         $this->assertSame('lala <object>xx</object>',
            array('<p class="frogs">This is a <strong class=\'fishes\'>test</strong></p>', FORMAT_HTML, 'This is a TEST'),
>             format_text($text, FORMAT_HTML, ['trusted' => true]));
            array("<span lang='en' class='multilang'>english</span>
> 
<span lang='ca' class='multilang'>català</span>
>         $this->assertSame(s($text),
<span lang='es' class='multilang'>español</span>
>             format_text($text, FORMAT_PLAIN, ['trusted' => false]));
<span lang='fr' class='multilang'>français</span>", FORMAT_HTML, "english català español français")
>         $this->assertSame("<p>lala xx</p>\n",
        );
>             format_text($text, FORMAT_MARKDOWN, ['trusted' => false]));
    }
>         $this->assertSame('<div class="text_to_html">lala xx</div>',

>             format_text($text, FORMAT_MOODLE, ['trusted' => false]));
    /**
>         $this->assertSame('lala xx',
     * Data provider for validate_email() function.
>             format_text($text, FORMAT_HTML, ['trusted' => false]));
     *
> 
     * @return array Returns aray of test data for the test_validate_email function
>         $this->assertSame("<p>lala <object>xx</object></p>\n",
     */
>             format_text($text, FORMAT_MARKDOWN, ['trusted' => true, 'noclean' => true]));
    public function data_validate_email() {
>         $this->assertSame("<p>lala <object>xx</object></p>\n",
        return [
>             format_text($text, FORMAT_MARKDOWN, ['trusted' => false, 'noclean' => true]));
            // Test addresses that should pass.
>     }
            [
> 
                'email' => 'moodle@example.com',
>     /**
                'result' => true
>      * @covers ::qualified_me
            ],
>      */



<     public function test_null_progres_trace() {



>     /**
>      * @covers \null_progress_trace
>      */
>     public function test_null_progress_trace() {



<     public function test_text_progres_trace() {



>     /**
>      * @covers \null_progress_trace
>      */
>     public function test_text_progress_trace() {



<     public function test_html_progres_trace() {



>     /**
>      * @covers \html_progress_trace
>      */
>     public function test_html_progress_trace() {


            ],

>     /**
            [
>      * @covers \html_list_progress_trace
                'email' => 'verp_email+is=mighty@moodle.org',
>      */



<     public function test_progres_trace_buffer() {



>     /**
>      * @covers \progress_trace_buffer
>      */
>     public function test_progress_trace_buffer() {



<     public function test_combined_progres_trace() {



>     /**
>      * @covers \combined_progress_trace
>      */
>     public function test_combined_progress_trace() {


            [

>     /**
                'email' => "but_potentially'dangerous'too@example.org",
>      * @covers ::set_debugging
                'result' => true
>      */


            ],

>     /**
            [
>      * @covers ::strip_pluginfile_content
                'email' => 'posts+AAAAAAAAAAIAAAAAAAAGQQAAAAABFSXz1eM/P/lR2bYyljM+@posts.moodle.org',
>      */


                'result' => true

>     /**
            ],
>      * @covers \purify_html

>      */


            // Test addresses that should NOT pass.

>      * @covers ::content_to_text


            [
                'email' => 'moodle@localhost',
                'result' => false
            ],
            [
                'email' => '"attacker\\" -oQ/tmp/ -X/var/www/vhost/moodle/backdoor.php  some"@email.com',
                'result' => false
            ],
            [
                'email' => "moodle@example.com>\r\nRCPT TO:<victim@example.com",
                'result' => false
            ],
            [
                'email' => 'greater>than@example.com',
                'result' => false
            ],
            [
                'email' => 'less<than@example.com',
                'result' => false
            ],
            [
                'email' => '"this<is>validbutwerejectit"@example.com',
                'result' => false
            ],


>             // Empty e-mail addresess are not valid.
            // Extra email addresses from Wikipedia page on Email Addresses.
>             [
            // Valid.
>                 'email' => '',
            [
>                 'result' => false,
                'email' => 'simple@example.com',
>             ],
                'result' => true
>             [
            ],
>                 'email' => null,
            [
>                 'result' => false,
                'email' => 'very.common@example.com',
>             ],
                'result' => true
>             [
            ],
>                 'email' => false,
            [
>                 'result' => false,
                'email' => 'disposable.style.email.with+symbol@example.com',
>             ],
                'result' => true
> 


            ],
            [
                'email' => 'other.email-with-hyphen@example.com',
                'result' => true
            ],
            [
                'email' => 'fully-qualified-domain@example.com',
                'result' => true
            ],
            [
                'email' => 'user.name+tag+sorting@example.com',
                'result' => true
            ],
            // One-letter local-part.
            [
                'email' => 'x@example.com',
                'result' => true
            ],
            [
                'email' => 'example-indeed@strange-example.com',
                'result' => true
            ],
            // See the List of Internet top-level domains.
            [
                'email' => 'example@s.example',
                'result' => true
            ],
            // Quoted double dot.
            [
                'email' => '"john..doe"@example.org',
                'result' => true
            ],

            // Invalid.
            // No @ character.
            [
                'email' => 'Abc.example.com',
                'result' => false
            ],
            // Only one @ is allowed outside quotation marks.
            [
                'email' => 'A@b@c@example.com',
                'result' => false
            ],
            // None of the special characters in this local-part are allowed outside quotation marks.
            [
                'email' => 'a"b(c)d,e:f;g<h>i[j\k]l@example.com',
                'result' => false
            ],
            // Quoted strings must be dot separated or the only element making up the local-part.
            [
                'email' => 'just"not"right@example.com',
                'result' => false
            ],
            // Spaces, quotes, and backslashes may only exist when within quoted strings and preceded by a backslash.
            [
                'email' => 'this is"not\allowed@example.com',
                'result' => false
            ],
            // Even if escaped (preceded by a backslash), spaces, quotes, and backslashes must still be contained by quotes.
            [
                'email' => 'this\ still\"not\\allowed@example.com',
                'result' => false
            ],
            // Local part is longer than 64 characters.
            [
                'email' => '1234567890123456789012345678901234567890123456789012345678901234+x@example.com',
                'result' => false
            ],
        ];
    }

    /**
     * Tests valid and invalid email address using the validate_email() function.
     *
     * @param string $email the email address to test
     * @param boolean $result Expected result (true or false)
     * @dataProvider    data_validate_email

>      * @covers ::validate_email


     */
    public function test_validate_email($email, $result) {
        if ($result) {
            $this->assertTrue(validate_email($email));
        } else {
            $this->assertFalse(validate_email($email));
        }
    }

    /**
     * Data provider for test_get_file_argument.
     */
    public static function provider_get_file_argument() {
        return array(
            // Serving SCORM content w/o HTTP GET params.
            array(array(
                    'SERVER_SOFTWARE' => 'Apache',
                    'SERVER_PORT' => '80',
                    'REQUEST_METHOD' => 'GET',
                    'REQUEST_URI' => '/pluginfile.php/3854/mod_scorm/content/1/swf.html',
                    'SCRIPT_NAME' => '/pluginfile.php',
                    'PATH_INFO' => '/3854/mod_scorm/content/1/swf.html',
                ), 0, '/3854/mod_scorm/content/1/swf.html'),
            array(array(
                    'SERVER_SOFTWARE' => 'Apache',
                    'SERVER_PORT' => '80',
                    'REQUEST_METHOD' => 'GET',
                    'REQUEST_URI' => '/pluginfile.php/3854/mod_scorm/content/1/swf.html',
                    'SCRIPT_NAME' => '/pluginfile.php',
                    'PATH_INFO' => '/3854/mod_scorm/content/1/swf.html',
                ), 1, '/3854/mod_scorm/content/1/swf.html'),
            // Serving SCORM content w/ HTTP GET 'file' as first param.
            array(array(
                    'SERVER_SOFTWARE' => 'Apache',
                    'SERVER_PORT' => '80',
                    'REQUEST_METHOD' => 'GET',
                    'REQUEST_URI' => '/pluginfile.php/3854/mod_scorm/content/1/swf.html?file=video_.swf',
                    'SCRIPT_NAME' => '/pluginfile.php',
                    'PATH_INFO' => '/3854/mod_scorm/content/1/swf.html',
                ), 0, '/3854/mod_scorm/content/1/swf.html'),
            array(array(
                    'SERVER_SOFTWARE' => 'Apache',
                    'SERVER_PORT' => '80',
                    'REQUEST_METHOD' => 'GET',
                    'REQUEST_URI' => '/pluginfile.php/3854/mod_scorm/content/1/swf.html?file=video_.swf',
                    'SCRIPT_NAME' => '/pluginfile.php',
                    'PATH_INFO' => '/3854/mod_scorm/content/1/swf.html',
                ), 1, '/3854/mod_scorm/content/1/swf.html'),
            // Serving SCORM content w/ HTTP GET 'file' not as first param.
            array(array(
                    'SERVER_SOFTWARE' => 'Apache',
                    'SERVER_PORT' => '80',
                    'REQUEST_METHOD' => 'GET',
                    'REQUEST_URI' => '/pluginfile.php/3854/mod_scorm/content/1/swf.html?foo=bar&file=video_.swf',
                    'SCRIPT_NAME' => '/pluginfile.php',
                    'PATH_INFO' => '/3854/mod_scorm/content/1/swf.html',
                ), 0, '/3854/mod_scorm/content/1/swf.html'),
            array(array(
                    'SERVER_SOFTWARE' => 'Apache',
                    'SERVER_PORT' => '80',
                    'REQUEST_METHOD' => 'GET',
                    'REQUEST_URI' => '/pluginfile.php/3854/mod_scorm/content/1/swf.html?foo=bar&file=video_.swf',
                    'SCRIPT_NAME' => '/pluginfile.php',
                    'PATH_INFO' => '/3854/mod_scorm/content/1/swf.html',
                ), 1, '/3854/mod_scorm/content/1/swf.html'),
            // Serving content from a generic activity w/ HTTP GET 'file', still forcing slash arguments.
            array(array(
                    'SERVER_SOFTWARE' => 'Apache',
                    'SERVER_PORT' => '80',
                    'REQUEST_METHOD' => 'GET',
                    'REQUEST_URI' => '/pluginfile.php/3854/whatever/content/1/swf.html?file=video_.swf',
                    'SCRIPT_NAME' => '/pluginfile.php',
                    'PATH_INFO' => '/3854/whatever/content/1/swf.html',
                ), 0, '/3854/whatever/content/1/swf.html'),
            array(array(
                    'SERVER_SOFTWARE' => 'Apache',
                    'SERVER_PORT' => '80',
                    'REQUEST_METHOD' => 'GET',
                    'REQUEST_URI' => '/pluginfile.php/3854/whatever/content/1/swf.html?file=video_.swf',
                    'SCRIPT_NAME' => '/pluginfile.php',
                    'PATH_INFO' => '/3854/whatever/content/1/swf.html',
                ), 1, '/3854/whatever/content/1/swf.html'),
            // Serving content from a generic activity w/ HTTP GET 'file', still forcing slash arguments (edge case).
            array(array(
                    'SERVER_SOFTWARE' => 'Apache',
                    'SERVER_PORT' => '80',
                    'REQUEST_METHOD' => 'GET',
                    'REQUEST_URI' => '/pluginfile.php/?file=video_.swf',
                    'SCRIPT_NAME' => '/pluginfile.php',
                    'PATH_INFO' => '/',
                ), 0, 'video_.swf'),
            array(array(
                    'SERVER_SOFTWARE' => 'Apache',
                    'SERVER_PORT' => '80',
                    'REQUEST_METHOD' => 'GET',
                    'REQUEST_URI' => '/pluginfile.php/?file=video_.swf',
                    'SCRIPT_NAME' => '/pluginfile.php',
                    'PATH_INFO' => '/',
                ), 1, 'video_.swf'),
            // Serving content from a generic activity w/ HTTP GET 'file', w/o forcing slash arguments.
            array(array(
                    'SERVER_SOFTWARE' => 'Apache',
                    'SERVER_PORT' => '80',
                    'REQUEST_METHOD' => 'GET',
                    'REQUEST_URI' => '/pluginfile.php?file=%2F3854%2Fwhatever%2Fcontent%2F1%2Fswf.html%3Ffile%3Dvideo_.swf',
                    'SCRIPT_NAME' => '/pluginfile.php',
                ), 0, '/3854/whatever/content/1/swf.html?file=video_.swf'),
            array(array(
                    'SERVER_SOFTWARE' => 'Apache',
                    'SERVER_PORT' => '80',
                    'REQUEST_METHOD' => 'GET',
                    'REQUEST_URI' => '/pluginfile.php?file=%2F3854%2Fwhatever%2Fcontent%2F1%2Fswf.html%3Ffile%3Dvideo_.swf',
                    'SCRIPT_NAME' => '/pluginfile.php',
                ), 1, '/3854/whatever/content/1/swf.html?file=video_.swf'),
        );
    }

    /**
     * Tests for get_file_argument() function.
     *
     * @param array $server mockup for $_SERVER.
     * @param string $cfgslasharguments slasharguments setting.
     * @param string|false $expected Expected value.
     * @dataProvider provider_get_file_argument

>      * @covers ::get_file_argument


     */
    public function test_get_file_argument($server, $cfgslasharguments, $expected) {
        global $CFG;

        // Overwrite the related settings.
        $currentsetting = $CFG->slasharguments;
        $CFG->slasharguments = $cfgslasharguments;
        // Mock global $_SERVER.
        $currentserver = isset($_SERVER) ? $_SERVER : null;
        $_SERVER = $server;
        initialise_fullme();
        if ($_SERVER['REQUEST_METHOD'] !== 'GET') {
            $this->fail('Only HTTP GET mocked request allowed.');
        }
        if (empty($_SERVER['REQUEST_URI'])) {
            $this->fail('Invalid HTTP GET mocked request.');
        }
        // Mock global $_GET.
        $currentget = isset($_GET) ? $_GET : null;
        $_GET = array();
        $querystring = parse_url($_SERVER['REQUEST_URI'], PHP_URL_QUERY);
        if (!empty($querystring)) {
            $_SERVER['QUERY_STRING'] = $querystring;
            parse_str($querystring, $_GET);
        }

        $this->assertEquals($expected, get_file_argument());

        // Restore the current settings and global values.
        $CFG->slasharguments = $currentsetting;
        if (is_null($currentserver)) {
            unset($_SERVER);
        } else {
            $_SERVER = $currentserver;
        }
        if (is_null($currentget)) {
            unset($_GET);
        } else {
            $_GET = $currentget;
        }
    }

    /**
     * Tests for extract_draft_file_urls_from_text() function.

>      *
     */
>      * @covers ::extract_draft_file_urls_from_text


    public function test_extract_draft_file_urls_from_text() {
        global $CFG;

        $url1 = "{$CFG->wwwroot}/draftfile.php/5/user/draft/99999999/test1.jpg";
        $url2 = "{$CFG->wwwroot}/draftfile.php/5/user/draft/99999998/test2.jpg";

        $html = "<p>This is a test.</p><p><img src=\"${url1}\" alt=\"\" role=\"presentation\"></p>
                <br>Test content.<p></p><p><img src=\"{$url2}\" alt=\"\" width=\"2048\" height=\"1536\"
                role=\"presentation\" class=\"img-fluid atto_image_button_text-bottom\"><br></p>";
        $draftareas = array(
            array(
                'urlbase' => 'draftfile.php',
                'contextid' => '5',
                'component' => 'user',
                'filearea' => 'draft',
                'itemid' => '99999999',
                'filename' => 'test1.jpg',
                0 => "{$CFG->wwwroot}/draftfile.php/5/user/draft/99999999/test1.jpg",
                1 => 'draftfile.php',
                2 => '5',
                3 => 'user',
                4 => 'draft',
                5 => '99999999',
                6 => 'test1.jpg'
            ),
            array(
                'urlbase' => 'draftfile.php',
                'contextid' => '5',
                'component' => 'user',
                'filearea' => 'draft',
                'itemid' => '99999998',
                'filename' => 'test2.jpg',
                0 => "{$CFG->wwwroot}/draftfile.php/5/user/draft/99999998/test2.jpg",
                1 => 'draftfile.php',
                2 => '5',
                3 => 'user',
                4 => 'draft',
                5 => '99999998',
                6 => 'test2.jpg'
            )
        );
        $extracteddraftareas = extract_draft_file_urls_from_text($html, false, 5, 'user', 'draft');
        $this->assertEquals($draftareas, $extracteddraftareas);
    }


>     /**
    public function test_print_password_policy() {
>      * @covers ::print_password_policy
        $this->resetAfterTest(true);
>      */


        global $CFG;

        $policydisabled = '';

        // Set password policy to disabled.
        $CFG->passwordpolicy = false;

        // Check for empty response.
        $this->assertEquals($policydisabled, print_password_policy());

        // Now set the policy to enabled with every control disabled.
        $CFG->passwordpolicy = true;
        $CFG->minpasswordlength = 0;
        $CFG->minpassworddigits = 0;
        $CFG->minpasswordlower = 0;
        $CFG->minpasswordupper = 0;
        $CFG->minpasswordnonalphanum = 0;
        $CFG->maxconsecutiveidentchars = 0;

        // Check for empty response.
        $this->assertEquals($policydisabled, print_password_policy());

        // Now enable some controls, and check that the policy responds with policy text.
        $CFG->minpasswordlength = 8;
        $CFG->minpassworddigits = 1;
        $CFG->minpasswordlower = 1;
        $CFG->minpasswordupper = 1;
        $CFG->minpasswordnonalphanum = 1;
        $CFG->maxconsecutiveidentchars = 1;

        $this->assertNotEquals($policydisabled, print_password_policy());

>     }
    }
> 
}
>     /**
>      * Data provider for the testing get_html_lang_attribute_value().
>      *
>      * @return string[][]
>      */
>     public function get_html_lang_attribute_value_provider() {
>         return [
>             'Empty lang code' => ['    ', 'en'],
>             'English' => ['en', 'en'],
>             'English, US' => ['en_us', 'en'],
>             'Unknown' => ['xx', 'en'],
>         ];
>     }
> 
>     /**
>      * Test for get_html_lang_attribute_value().
>      *
>      * @covers ::get_html_lang_attribute_value()
>      * @dataProvider get_html_lang_attribute_value_provider
>      * @param string $langcode The language code to convert.
>      * @param string $expected The expected converted value.
>      * @return void
>      */
>     public function test_get_html_lang_attribute_value(string $langcode, string $expected): void {
>         $this->assertEquals($expected, get_html_lang_attribute_value($langcode));
>     }
> 
>     /**
>      * Data provider for strip_querystring tests.
>      *
>      * @return array
>      */
>     public function strip_querystring_provider(): array {
>         return [
>             'Null' => [null, ''],
>             'Empty string' => ['', ''],
>             'No querystring' => ['https://example.com', 'https://example.com'],
>             'Querystring' => ['https://example.com?foo=bar', 'https://example.com'],
>             'Querystring with fragment' => ['https://example.com?foo=bar#baz', 'https://example.com'],
>             'Querystring with fragment and path' => ['https://example.com/foo/bar?foo=bar#baz', 'https://example.com/foo/bar'],
>         ];
>     }
> 
>     /**
>      * Test the strip_querystring function with various exampels.
>      *
>      * @dataProvider strip_querystring_provider
>      * @param mixed $value
>      * @param mixed $expected
>      * @covers ::strip_querystring
>      */
>     public function test_strip_querystring($value, $expected): void {
>         $this->assertEquals($expected, strip_querystring($value));