Index: canonical/permalinkFormats.php
===================================================================
--- canonical/permalinkFormats.php	(revision 0)
+++ canonical/permalinkFormats.php	(working copy)
@@ -0,0 +1,80 @@
+<?php
+
+/**
+ * @group canonical
+ * @group rewrite
+ * @group query
+ */
+class Tests_Canonical_PermalinkFormat extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 21167
+	 */
+	public function test_dotted_formats() {
+		global $wp_rewrite;
+
+		// Create a sample post
+		$cat_id = $this->factory->term->create( array(
+			'name'     => 'permalink-test',
+			'taxonomy' => 'category'
+		) );
+		$user_id = $this->factory->user->create( array(
+			'role'       => 'editor',
+			'user_login' => 'permalink_user',
+		) );
+		$post_id = $this->factory->post->create( array(
+			'post_title' => 'lorem-ipsum',
+			'post_date'  => '2012-08-02 14:15:05',
+			'post_author' => $user_id,
+			'category'    => $cat_id
+		) );
+		wp_set_post_categories( $post_id, array( $cat_id ) );
+
+		// Sample permalinks
+		$tests = array(
+			'/%postname%.%post_id%/ '        => array(
+				'regex' => '([^/]+)\.([0-9]+)(/[0-9]+)?/?$',
+				'url'   => 'index.php?name=$1&p=$2&page=$3'
+			),
+			'/%year%.%monthnum%.%postname%/' => array(
+				'regex' => '([0-9]{4})\.([0-9]{1,2})\.([^/]+)(/[0-9]+)?/?$',
+				'url'   => 'index.php?year=$1&monthnum=$2&name=$3&page=$4'
+			),
+			'/%post_id%.%postname%/'         => array(
+				'regex' => '([0-9]+)\.([^/]+)(/[0-9]+)?/?$',
+				'url'   => 'index.php?p=$1&name=$2&page=$3'
+			),
+			'/%postname%.%year%/'            => array(
+				'regex' => '([^/]+)\.([0-9]{4})(/[0-9]+)?/?$',
+				'url'   => 'index.php?name=$1&year=$2&page=$3'
+			),
+			'/$%postname%$/'                 => array(
+				'regex' => '\$([^/]+)\$(/[0-9]+)?/?$',
+				'url'   => 'index.php?name=$1&page=$2'
+			),
+			'%year%.+?%monthnum%.+?%day%.+?%hour%.+?%minute%.+?%second%.+?%post_id%.+?%postname%.+?%category%.+?%author%.+?' => array(
+				'regex' => '([0-9]{4})\.\+\?([0-9]{1,2})\.\+\?([0-9]{1,2})\.\+\?([0-9]{1,2})\.\+\?([0-9]{1,2})\.\+\?([0-9]{1,2})\.\+\?([0-9]+)\.\+\?([^/]+)\.\+\?%category%\.\+\?([^/]+)\.\+\?(/[0-9]+)?/?$',
+				'url'   => 'index.php?year=$1&monthnum=$2&day=$3&hour=$4&minute=$5&second=$6&p=$7&name=$8&%category%$9&author_name=$10&page=$11'
+			)
+		);
+
+		// Test permalinks
+		foreach ( $tests as $permalink_format => $expected ) {
+			update_option( 'permalink_structure', $permalink_format );
+			
+			// Get the rewrite rules
+			$rules = $wp_rewrite->generate_rewrite_rules( get_option( 'permalink_structure' ), EP_PERMALINK, false, false, false, false );
+			
+			// Filter out only the post rewrite rule
+			foreach ( $rules as $regex => $url ) {
+				if ( false === strpos( $url, 'attachment=$' ) && false === strpos( $url, 'tb=' ) && false === strpos( $url, 'cpage=$' ) ) {
+					break;
+				}
+			}
+
+			// Test that expected === actual			
+			$this->assertEquals( $regex, $expected['regex'], "Problem with permalink format: $permalink_format" );
+			$this->assertEquals( $url, $expected['url'], "Problem with permalink format: $permalink_format" );
+		}
+	}
+}