Index: tests/phpunit/tests/formatting/Autop.php
===================================================================
--- tests/phpunit/tests/formatting/Autop.php	(revision 29400)
+++ tests/phpunit/tests/formatting/Autop.php	(working copy)
@@ -400,4 +400,14 @@
 
 		$this->assertEquals( $expected, trim( wpautop( $content ) ) );
 	}
+
+	/**
+	 * wpautop() should ignore content without line breaks
+	 *
+	 * @ticket 20444
+	 */
+	function test_unbroken_lines() {
+		$str = "<div><p>Hello world</p><span>WordPress</span></div>";
+		$this->assertEquals( "<div>\n<p>Hello world</p>\n<p><span>WordPress</span></p>\n</div>", trim( wpautop( $str ) ) );
+	}
 }