Add UI to select an offline page

pwa.php

@@ -40,7 +40,12 @@
 /** Amend default filters */
 require PWA_PLUGIN_DIR . '/wp-includes/default-filters.php';
 
+/** WP_Offline_Page Class */
+require PWA_PLUGIN_DIR . '/wp-includes/class-wp-offline-page.php';
+
 $wp_web_app_manifest = new WP_Web_App_Manifest();
 $wp_web_app_manifest->init();
 $wp_https_detection = new WP_HTTPS_Detection();
 $wp_https_detection->init();
+$wp_offline_page = new WP_Offline_Page();
+$wp_offline_page->init();

tests/test-class-wp-offline-page-excluder.php

@@ -0,0 +1,128 @@
+<?php
+/**
+ * Tests for class WP_Offline_Page_Excluder.
+ *
+ * @package PWA
+ */
+
+/**
+ * Tests for class WP_Offline_Page_Excluder.
+ */
+class Test_WP_Offline_Page_Excluder extends WP_UnitTestCase {
+
+	/**
+	 * Tested instance.
+	 *
+	 * @var WP_Offline_Page_Excluder
+	 */
+	public $instance;
+
+	/**
+	 * Setup.
+	 *
+	 * @inheritdoc
+	 */
+	public function setUp() {
+		parent::setUp();
+		$this->instance = new WP_Offline_Page_Excluder( new WP_Offline_Page() );
+	}
+
+	/**
+	 * Test init.
+	 *
+	 * @covers WP_Offline_Page_Excluder::init()
+	 */
+	public function test_init() {
+		$this->instance->init();
+		$this->assertEquals( 10, has_filter( 'wp_dropdown_pages', array( $this->instance, 'exclude_from_page_dropdown' ) ) );
+		$this->assertEquals( 10, has_filter( 'parse_query', array( $this->instance, 'exclude_from_query' ) ) );
+	}
+
+	/**
+	 * Test exclude_from_page_dropdown.
+	 *
+	 * @covers WP_Offline_Page_Excluder::exclude_from_page_dropdown()
+	 */
+	public function test_exclude_from_page_dropdown() {
+		$page_id = $this->factory()->post->create( array( 'post_type' => 'page' ) );
+		$html    = <<<EOB
+<select name="page_on_front" id="page_on_front">
+	<option value="0">— Select —</option>
+	<option class="level-0" value="7">Blog Page</option>
+	<option class="level-0" value="5" selected="selected">Home page</option>
+	<option class="level-0" value="13">Offline Page</option>	
+	<option class="level-0" value="3">Privacy Policy</option>
+	<option class="level-0" value="2">Sample Page</option>
+</select>
+EOB;
+		$html    = str_replace( '13', $page_id, $html );
+
+		// Check that the HTML is unchanged when no Offline Page exists.
+		$this->assertSame(
+			$html,
+			$this->instance->exclude_from_page_dropdown( $html, array( 'name' => 'page_on_front' ) )
+		);
+
+		// Add the Offline Page and recheck.
+		add_option( WP_Offline_Page::OPTION_NAME, $page_id );
+		$this->assertNotContains(
+			'<option class="level-0" value="' . $page_id . '">Offline Page</option>',
+			$this->instance->exclude_from_page_dropdown( $html, array( 'name' => 'page_on_front' ) )
+		);
+	}
+
+	/**
+	 * Test is_exclude_from_query.
+	 *
+	 * @covers WP_Offline_Page_Excluder::is_exclude_from_query()
+	 */
+	public function test_is_exclude_from_query() {
+		set_current_screen( 'front' );
+
+		$offline_id = $this->factory()->post->create( array(
+			'post_type'  => 'page',
+			'post_title' => 'Offline page',
+		) );
+		$page_id    = $this->factory()->post->create( array(
+			'post_type'  => 'page',
+			'post_title' => 'Accessing via Offline',
+		) );
+		add_option( WP_Offline_Page::OPTION_NAME, $offline_id );
+		add_action( 'parse_query', array( $this->instance, 'exclude_from_query' ) );
+
+		// Check a page.
+		$this->go_to( get_permalink( $page_id ) );
+		$this->assertEquals( array( $offline_id ), get_query_var( 'post__not_in' ) );
+		$this->assertSame( $page_id, get_queried_object()->ID );
+
+		// Check search.
+		$this->go_to( '?s=Offline' );
+		$this->assertEquals( array( $offline_id ), get_query_var( 'post__not_in' ) );
+		$this->assertTrue( have_posts() );
+		$this->assertEquals( 1, $GLOBALS['wp_query']->post_count );
+
+		// Check edit.php.
+		set_current_screen( 'edit.php' );
+		$this->go_to( admin_url( 'edit.php' ) );
+		$this->assertEquals( array(), get_query_var( 'post__not_in' ) );
+
+		// Check that is is excluded on the nav-menu.php query.
+		set_current_screen( 'nav-menus.php' );
+		$this->go_to( admin_url( 'nav-menus.php' ) );
+		$this->assertEquals( array( $offline_id ), get_query_var( 'post__not_in' ) );
+
+		set_current_screen( 'front' );
+
+		// Check that the offline page is found when using the plan permalink.
+		$this->go_to( "?page_id={$offline_id}" );
+		$this->assertEquals( array( $offline_id ), get_query_var( 'post__not_in' ) );
+		$this->assertFalse( $GLOBALS['wp_query']->is_404() );
+		$this->assertSame( $offline_id, get_queried_object()->ID );
+
+		// Check that the offline page flags a 404.
+		$this->set_permalink_structure( '/%postname%/' );
+		$this->go_to( get_permalink( $offline_id ) );
+		$this->assertEquals( array( $offline_id ), get_query_var( 'post__not_in' ) );
+		$this->assertTrue( $GLOBALS['wp_query']->is_404() );
+	}
+}