Index: tests/rewrite.php
===================================================================
--- tests/rewrite.php	(revision 0)
+++ tests/rewrite.php	(revision 0)
@@ -0,0 +1,93 @@
+<?php
+
+/**
+ * A set of unit tests for functions in wp-includes/rewrite.php
+ * 
+ * @group rewrite
+ */ 
+class Tests_Rewrite extends WP_UnitTestCase {
+
+	function setUp() {
+		parent::setUp();
+
+		// Need rewrite rules in place to use url_to_postid
+		global $wp_rewrite;
+		update_option( 'permalink_structure', '/%year%/%monthnum%/%day%/%postname%/' );
+		create_initial_taxonomies();
+		$GLOBALS['wp_rewrite']->init();
+		flush_rewrite_rules();
+	}
+
+	function tearDown() {
+		parent::tearDown();
+		$GLOBALS['wp_rewrite']->init();
+	}
+
+	function test_url_to_postid() {
+
+		$id = $this->factory->post->create();
+		$this->assertEquals( $id, url_to_postid( get_permalink( $id ) ) );
+
+	}
+
+	function test_url_to_postid_hierarchical() {
+
+		$parent_id = $this->factory->post->create( array( 'post_title' => 'Parent', 'post_type' => 'page' ) );
+		$child_id = $this->factory->post->create( array( 'post_title' => 'Child', 'post_type' => 'page', 'post_parent' => $parent_id ) );
+
+		$this->assertEquals( $parent_id, url_to_postid( get_permalink( $parent_id ) ) );
+		$this->assertEquals( $child_id, url_to_postid( get_permalink( $child_id ) ) );
+
+	}
+
+	/**
+	 * Reveals bug introduced in WP 3.0
+	 * 
+	 * @ticket 20560
+	 */ 
+	function test_url_to_postid_home_url_collision() {
+
+		$this->knownWPBug(20560);
+
+		update_option( 'home', home_url('/example') );
+
+		$this->factory->post->create( array( 'post_title' => 'Collision', 'post_type' => 'page' ) );
+
+		// This url should NOT return a post ID
+		$badurl = site_url('/example-collision');
+		$this->assertEquals( 0, url_to_postid( $badurl ) );
+
+	}
+
+	/**
+	 * Reveals bug introduced in WP 3.0
+	 * 
+	 * Run tests using multisite `phpunit -c multisite`
+	 * 
+	 * @ticket 20560
+	 */ 
+	function test_url_to_postid_ms_home_url_collision() {
+
+		if( ! is_multisite() ) {
+			$this->markTestSkipped('test_url_to_postid_ms_home_url_collision requires multisite');
+			return false;
+		} 
+
+		$this->knownWPBug(20560);
+
+		$blog_id = $this->factory->blog->create( array( 'path' => '/example' ) );
+		switch_to_blog( $blog_id );
+
+		$this->factory->post->create( array( 'post_title' => 'Collision ', 'post_type' => 'page' ) );
+
+		// This url should NOT return a post ID
+		$badurl = network_home_url('/example-collision');
+		$this->assertEquals( 0, url_to_postid( $badurl ) );
+
+		restore_current_blog();
+
+	}
+
+}
+
+?>
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