Index: tests/phpunit/tests/formatting/Autop-Newline-Preservation-Helper.php
===================================================================
--- tests/phpunit/tests/formatting/Autop-Newline-Preservation-Helper.php	(nonexistent)
+++ tests/phpunit/tests/formatting/Autop-Newline-Preservation-Helper.php	(working copy)
@@ -0,0 +1,39 @@
+<?php
+/**
+ * The Tests_Autop_Newline_Preservation_Helper() from Formatter
+ *
+ * @group formatting
+ */
+class Tests_Autop_Newline_Preservation_Helper extends WP_UnitTestCase {
+
+	/**
+	 * data provider
+	 *
+	 * @return array
+	 */
+	function data_autop_newline_preservation_helper() {
+		return array(
+			array( PHP_EOL, '<WPPreserveNewline />', ' 1 PHP_EOL' ),
+			array( "
+			", '<WPPreserveNewline />', 'passing line return in string' ),
+			array( '/n', '/', ' passing /n in string' ),
+			array( 'd', 'd', ' just a d ' ),
+			array( 'd' . PHP_EOL, 'd', ' just a d ' ),
+		);
+	}
+
+	/**
+	 * @dataProvider data_autop_newline_preservation_helper
+	 * @covers ::_autop_newline_preservation_helper
+	 *
+	 * @param $input
+	 * @param $expected
+	 * @param $message
+	 */
+	function test_autop_newline_preservation_helper( $input, $expected, $message ) {
+
+		$this->assertSame( $expected, _autop_newline_preservation_helper( $input ), $message );
+	}
+
+
+}