Tests: Add unit test coverage for WP_Widget_Calendar

tests/phpunit/tests/widgets/wpWidgetCalendar.php

@@ -0,0 +1,271 @@
+<?php
+/**
+ * Unit tests covering WP_Widget_Calendar functionality.
+ *
+ * @package    WordPress
+ * @subpackage widgets
+ */
+
+/**
+ * Test wp-includes/widgets/class-wp-widget-calendar.php
+ *
+ * @group widgets
+ *
+ * @covers WP_Widget_Calendar
+ */
+class Tests_Widgets_wpWidgetCalendar extends WP_UnitTestCase {
+
+	/**
+	 * Default widget arguments.
+	 *
+	 * @var array
+	 */
+	protected $args = array(
+		'before_widget' => '<section id="calendar-2" class="widget widget_calendar">',
+		'after_widget'  => "</section>\n",
+		'before_title'  => '<h2 class="widget-title">',
+		'after_title'   => "</h2>\n",
+	);
+
+	/**
+	 * Reset the private static $instance counter on WP_Widget_Calendar.
+	 */
+	public function set_up() {
+		parent::set_up();
+		$this->reset_calendar_widget_instance_count();
+	}
+
+	/**
+	 * Reset the private static $instance counter after each test.
+	 */
+	public function tear_down() {
+		$this->reset_calendar_widget_instance_count();
+		parent::tear_down();
+	}
+
+	/**
+	 * Helper to reset private static $instance count using reflection.
+	 */
+	private function reset_calendar_widget_instance_count() {
+		$property = new ReflectionProperty( 'WP_Widget_Calendar', 'instance' );
+		if ( PHP_VERSION_ID < 80100 ) {
+			$property->setAccessible( true );
+		}
+		$property->setValue( null, 0 );
+	}
+
+	/**
+	 * Tests the constructor settings and options.
+	 *
+	 * @ticket 65819
+	 *
+	 * @covers WP_Widget_Calendar::__construct
+	 */
+	public function test_construct() {
+		$widget = new WP_Widget_Calendar();
+
+		$this->assertSame( 'calendar', $widget->id_base );
+		$this->assertSame( 'Calendar', $widget->name );
+		$this->assertSame( 'widget_calendar', $widget->widget_options['classname'] );
+		$this->assertSame( 'A calendar of your site’s posts.', $widget->widget_options['description'] );
+		$this->assertTrue( $widget->widget_options['customize_selective_refresh'] );
+		$this->assertTrue( $widget->widget_options['show_instance_in_rest'] );
+	}
+
+	/**
+	 * Tests widget() output with default arguments and no title.
+	 *
+	 * @ticket 65819
+	 *
+	 * @covers WP_Widget_Calendar::widget
+	 */
+	public function test_widget_output_without_title() {
+		// get_calendar() outputs nothing unless at least one post exists.
+		self::factory()->post->create();
+
+		$widget   = new WP_Widget_Calendar();
+		$instance = array();
+
+		$output = get_echo( array( $widget, 'widget' ), array( $this->args, $instance ) );
+
+		$this->assertStringStartsWith( '<section id="calendar-2" class="widget widget_calendar">', $output );
+		$this->assertStringEndsWith( "</section>\n", $output );
+		$this->assertStringNotContainsString( 'widget-title', $output );
+		$this->assertStringContainsString( '<div id="calendar_wrap" class="calendar_wrap">', $output );
+		$this->assertStringContainsString( '<table id="wp-calendar"', $output );
+	}
+
+	/**
+	 * Tests that widget() outputs an empty calendar wrapper when there are no posts.
+	 *
+	 * @ticket 65819
+	 *
+	 * @covers WP_Widget_Calendar::widget
+	 */
+	public function test_widget_output_without_posts() {
+		/*
+		 * get_calendar() skips its "no posts" check when the global $posts is populated,
+		 * which can happen when it is left over from a previous test.
+		 */
+		unset( $GLOBALS['posts'] );
+
+		$widget   = new WP_Widget_Calendar();
+		$instance = array();
+
+		$output = get_echo( array( $widget, 'widget' ), array( $this->args, $instance ) );
+
+		$this->assertStringContainsString( '<div id="calendar_wrap" class="calendar_wrap"></div>', $output );
+		$this->assertStringNotContainsString( '<table id="wp-calendar"', $output );
+	}
+
+	/**
+	 * Tests widget() output with a custom title.
+	 *
+	 * @ticket 65819
+	 *
+	 * @covers WP_Widget_Calendar::widget
+	 */
+	public function test_widget_output_with_title() {
+		$widget   = new WP_Widget_Calendar();
+		$instance = array( 'title' => 'Events Calendar' );
+
+		$output = get_echo( array( $widget, 'widget' ), array( $this->args, $instance ) );
+
+		$this->assertStringContainsString( '<h2 class="widget-title">Events Calendar</h2>', $output );
+		$this->assertStringContainsString( '<div id="calendar_wrap" class="calendar_wrap">', $output );
+	}
+
+	/**
+	 * Tests that only the first widget instance receives the id attribute on calendar_wrap.
+	 *
+	 * @ticket 65819
+	 *
+	 * @covers WP_Widget_Calendar::widget
+	 */
+	public function test_widget_instance_counter_omits_id_on_subsequent_calls() {
+		$widget   = new WP_Widget_Calendar();
+		$instance = array();
+
+		$output1 = get_echo( array( $widget, 'widget' ), array( $this->args, $instance ) );
+		$output2 = get_echo( array( $widget, 'widget' ), array( $this->args, $instance ) );
+
+		$this->assertStringContainsString( '<div id="calendar_wrap" class="calendar_wrap">', $output1 );
+		$this->assertStringContainsString( '<div class="calendar_wrap">', $output2 );
+		$this->assertStringNotContainsString( '<div id="calendar_wrap"', $output2 );
+	}
+
+	/**
+	 * Tests that widget_title filter modifies the title.
+	 *
+	 * @ticket 65819
+	 *
+	 * @covers WP_Widget_Calendar::widget
+	 */
+	public function test_widget_applies_widget_title_filter() {
+		$widget   = new WP_Widget_Calendar();
+		$instance = array( 'title' => 'Initial Title' );
+
+		$filter = new MockAction();
+		add_filter( 'widget_title', array( $filter, 'filter' ), 10, 3 );
+		add_filter(
+			'widget_title',
+			static function () {
+				return 'Filtered Calendar Title';
+			},
+			20
+		);
+
+		$output = get_echo( array( $widget, 'widget' ), array( $this->args, $instance ) );
+
+		$this->assertStringContainsString( '<h2 class="widget-title">Filtered Calendar Title</h2>', $output );
+		$this->assertSame(
+			array( array( 'Initial Title', $instance, 'calendar' ) ),
+			$filter->get_args(),
+			'The widget_title filter should receive the title, instance, and id_base.'
+		);
+	}
+
+	/**
+	 * Tests update() method sanitizes the title field.
+	 *
+	 * @ticket 65819
+	 *
+	 * @covers WP_Widget_Calendar::update
+	 *
+	 * @dataProvider data_update_titles
+	 *
+	 * @param string $title    Submitted title.
+	 * @param string $expected Expected sanitized title.
+	 */
+	public function test_update_sanitizes_title( $title, $expected ) {
+		$widget = new WP_Widget_Calendar();
+
+		$new_instance = array( 'title' => $title );
+		$old_instance = array( 'title' => 'Old Title' );
+
+		$result = $widget->update( $new_instance, $old_instance );
+
+		$this->assertSame( array( 'title' => $expected ), $result );
+	}
+
+	/**
+	 * Data provider for test_update_sanitizes_title.
+	 *
+	 * @return array[]
+	 */
+	public static function data_update_titles() {
+		return array(
+			'plain string'           => array( 'My Calendar', 'My Calendar' ),
+			'with html tags'         => array( 'Calendar <strong>2026</strong> <script>alert(1)</script>', 'Calendar 2026' ),
+			'with line breaks'       => array( "Calendar\nYear", 'Calendar Year' ),
+			'surrounding whitespace' => array( '  Calendar  ', 'Calendar' ),
+			'empty string'           => array( '', '' ),
+			'numeric string zero'    => array( '0', '0' ),
+		);
+	}
+
+	/**
+	 * Tests form() output displays title field correctly.
+	 *
+	 * @ticket 65819
+	 *
+	 * @covers WP_Widget_Calendar::form
+	 *
+	 * @dataProvider data_form_titles
+	 *
+	 * @param array  $instance Widget settings instance.
+	 * @param string $expected Expected value in the input field.
+	 */
+	public function test_form_displays_title_field( $instance, $expected ) {
+		$widget = new WP_Widget_Calendar();
+		$widget->_set( 2 );
+
+		$output    = get_echo( array( $widget, 'form' ), array( $instance ) );
+		$processor = new WP_HTML_Tag_Processor( $output );
+
+		$this->assertTrue( $processor->next_tag( 'LABEL' ), 'The form should contain a label tag.' );
+		$this->assertSame( 'widget-calendar-2-title', $processor->get_attribute( 'for' ) );
+
+		$this->assertTrue( $processor->next_tag( 'INPUT' ), 'The form should contain an input tag.' );
+		$this->assertSame( 'widget-calendar-2-title', $processor->get_attribute( 'id' ) );
+		$this->assertSame( 'widget-calendar[2][title]', $processor->get_attribute( 'name' ) );
+		$this->assertSame( 'text', $processor->get_attribute( 'type' ) );
+		$this->assertSame( $expected, $processor->get_attribute( 'value' ) );
+		$this->assertFalse( $processor->next_tag( 'INPUT' ), 'The form should contain only one input field.' );
+	}
+
+	/**
+	 * Data provider for test_form_displays_title_field.
+	 *
+	 * @return array[]
+	 */
+	public static function data_form_titles() {
+		return array(
+			'with title'        => array( array( 'title' => 'Events Calendar' ), 'Events Calendar' ),
+			'with quotes'       => array( array( 'title' => 'Calendar "2026" & Beyond' ), 'Calendar "2026" & Beyond' ),
+			'empty title'       => array( array( 'title' => '' ), '' ),
+			'no title key'      => array( array(), '' ),
+			'zero string title' => array( array( 'title' => '0' ), '0' ),
+		);
+	}
+}