diff --git a/src/Csv.php b/src/Csv.php
index fdb34ab..1143140 100644
--- a/src/Csv.php
+++ b/src/Csv.php
@@ -300,14 +300,15 @@ class Csv {
      * Class constructor
      *
      * @param  string|null  $input          The CSV string or a direct filepath
-     * @param  integer|null $offset         Number of rows to ignore from the beginning
-     *                                      of  the data
-     * @param  integer|null $limit          Limits the number of returned rows to
-     *                                      specified amount
+     * @param  integer|null $offset         Number of rows to ignore from the
+     *                                      beginning of  the data
+     * @param  integer|null $limit          Limits the number of returned rows
+     *                                      to specified amount
      * @param  string|null  $conditions     Basic SQL-like conditions for row
      *                                      matching
      * @param  null|true    $keep_file_data Keep raw file data in memory after
-     *                                      successful parsing (useful for debugging)
+     *                                      successful parsing
+     *                                      (useful for debugging)
      */
     public function __construct($input = null, $offset = null, $limit = null, $conditions = null, $keep_file_data = null) {
         $this->init($offset, $limit, $conditions, $keep_file_data);
@@ -318,14 +319,15 @@ class Csv {
     }
 
     /**
-     * @param  integer|null $offset         Number of rows to ignore from the beginning
-     *                                      of  the data
-     * @param  integer|null $limit          Limits the number of returned rows to
-     *                                      specified amount
+     * @param  integer|null $offset         Number of rows to ignore from the
+     *                                      beginning of  the data
+     * @param  integer|null $limit          Limits the number of returned rows
+     *                                      to specified amount
      * @param  string|null  $conditions     Basic SQL-like conditions for row
      *                                      matching
      * @param  null|true    $keep_file_data Keep raw file data in memory after
-     *                                      successful parsing (useful for debugging)
+     *                                      successful parsing
+     *                                      (useful for debugging)
      */
     public function init($offset = null, $limit = null, $conditions = null, $keep_file_data = null) {
         if (!is_null($offset)) {
@@ -354,9 +356,12 @@ class Csv {
      * Parse a CSV file or string
      *
      * @param  string|null $input      The CSV string or a direct filepath
-     * @param  integer     $offset     Number of rows to ignore from the beginning of  the data
-     * @param  integer     $limit      Limits the number of returned rows to specified amount
-     * @param  string      $conditions Basic SQL-like conditions for row matching
+     * @param  integer     $offset     Number of rows to ignore from the
+     *                                 beginning of  the data
+     * @param  integer     $limit      Limits the number of returned rows to
+     *                                 specified amount
+     * @param  string      $conditions Basic SQL-like conditions for row
+     *                                 matching
      *
      * @return bool True on success
      */
@@ -366,13 +371,11 @@ class Csv {
         }
 
         if (empty($input)) {
-            // todo: but why true?
-            return true;
+            return false;
         }
 
         $this->init($offset, $limit, $conditions);
 
-
         if (strlen($input) <= PHP_MAXPATHLEN && is_readable($input)) {
             $this->file = $input;
             $this->data = $this->parse_file();
@@ -382,12 +385,7 @@ class Csv {
             $this->data = $this->parse_string();
         }
 
-        if ($this->data === false) {
-            return false;
-        }
-
-        return true;
-
+        return $this->data !== false;
     }
 
     /**
@@ -396,8 +394,10 @@ class Csv {
      *
      * @param  string $file   File location to save to
      * @param  array  $data   2D array of data
-     * @param  bool   $append Append current data to end of target CSV, if file exists
-     * @param  array  $fields Field names. Sets the header. If it is not set $this->titles would be used instead.
+     * @param  bool   $append Append current data to end of target CSV, if file
+     *                        exists
+     * @param  array  $fields Field names. Sets the header. If it is not set
+     *                        $this->titles would be used instead.
      *
      * @return bool
      */
@@ -419,7 +419,10 @@ class Csv {
      * @param  string|null $filename   If a filename is specified here or in the
      *                                 object, headers and data will be output
      *                                 directly to browser as a downloadable
-     *                                 file.
+     *                                 file. This file doesn't have to exist on
+     *                                 the server; the parameter only affects
+     *                                 how the download is called to the
+     *                                 browser.
      * @param  array[]     $data       2D array with data
      * @param  array       $fields     Field names
      * @param  string|null $delimiter  character used to separate data
@@ -527,8 +530,8 @@ class Csv {
     }
 
     /**
-     * Get total number of data rows (exclusive heading line if present) in csv
-     * without parsing whole data.
+     * Get total number of data rows (exclusive heading line if present) in CSV
+     * without parsing the whole data string.
      *
      * @return bool|int
      */
@@ -541,9 +544,10 @@ class Csv {
 
         $this->_detect_and_remove_sep_row_from_data($data);
 
-        $pattern = sprintf('/(%1$s[^%1$s]*%1$s)/i', $this->enclosure);
+        $pattern = sprintf('/%1$s[^%1$s]*%1$s/i', $this->enclosure);
         preg_match_all($pattern, $data, $matches);
 
+        /** @var array[] $matches */
         foreach ($matches[0] as $match) {
             if (empty($match) || (strpos($match, $this->enclosure) === false)) {
                 continue;
@@ -781,6 +785,9 @@ class Csv {
     public function unparse($data = array(), $fields = array(), $append = FileProcessingModeEnum::MODE_FILE_OVERWRITE, $is_php = false, $delimiter = null) {
         if (!is_array($data) || empty($data)) {
             $data = &$this->data;
+        } else {
+            /** @noinspection ReferenceMismatchInspection */
+            $this->data = $data;
         }
 
         if (!is_array($fields) || empty($fields)) {
@@ -795,6 +802,7 @@ class Csv {
         $entry = array();
 
         // create heading
+        /** @noinspection ReferenceMismatchInspection */
         $fieldOrder = $this->_validate_fields_for_unparse($fields);
         if (!$fieldOrder && !empty($data)) {
             $column_count = count($data[0]);
@@ -813,7 +821,7 @@ class Csv {
 
         // create data
         foreach ($data as $key => $row) {
-            foreach (array_keys($fieldOrder) as $index){
+            foreach (array_keys($fieldOrder) as $index) {
                 $cell_value = $row[$index];
                 $entry[] = $this->_enclose_value($cell_value, $delimiter);
             }
@@ -829,19 +837,20 @@ class Csv {
         return $string;
     }
 
-    private function _validate_fields_for_unparse($fields){
-        // this is needed because sometime titles property is overwritten instead of using fields parameter!
-        $titlesOnParse = !empty($this->data) ? array_keys($this->data[0]) : array();
-        if (empty($fields)){
+    private function _validate_fields_for_unparse($fields) {
+        if (empty($fields)) {
             $fields = $this->titles;
         }
 
-        if (empty($fields)){
+        if (empty($fields)) {
             return array();
         }
 
+        // this is needed because sometime titles property is overwritten instead of using fields parameter!
+        $titlesOnParse = !empty($this->data) ? array_keys($this->data[0]) : array();
+
         // both are identical, also in ordering
-        if (array_values($fields) === array_values($titlesOnParse)){
+        if (array_values($fields) === array_values($titlesOnParse)) {
             return array_combine($fields, $fields);
         }
 
@@ -859,7 +868,10 @@ class Csv {
 
         // original titles are not given in fields. that is okay if count is okay.
         if (count($fields) != count($titlesOnParse)) {
-            throw new \UnexpectedValueException('The specified fields do not match any titles and do not match column count.');
+            throw new \UnexpectedValueException(
+                "The specified fields do not match any titles and do not match column count.\n" .
+                "\$fields was " . print_r($fields, true) .
+                "\$titlesOnParse was " . print_r($titlesOnParse, true));
         }
 
         return array_combine($titlesOnParse, $fields);
@@ -1007,16 +1019,14 @@ class Csv {
             $op = $capture[2];
             $value = $capture[3];
 
-            if (preg_match('/^([\'\"]{1})(.*)([\'\"]{1})$/', $value, $capture)) {
-                if ($capture[1] == $capture[3]) {
-                    $value = strtr($capture[2], array(
-                        "\\n" => "\n",
-                        "\\r" => "\r",
-                        "\\t" => "\t",
-                    ));
+            if (preg_match('/^([\'\"]{1})(.*)([\'\"]{1})$/', $value, $capture) && $capture[1] == $capture[3]) {
+                $value = strtr($capture[2], array(
+                    "\\n" => "\n",
+                    "\\r" => "\r",
+                    "\\t" => "\t",
+                ));
 
-                    $value = stripslashes($value);
-                }
+                $value = stripslashes($value);
             }
 
             if (array_key_exists($field, $row)) {
diff --git a/tests/methods/DataRowCountTest.php b/tests/methods/DataRowCountTest.php
index 693d736..a256fde 100644
--- a/tests/methods/DataRowCountTest.php
+++ b/tests/methods/DataRowCountTest.php
@@ -64,7 +64,6 @@ class DataRowCountTest extends TestCase {
         $this->assertEquals(3, $this->csv->getTotalDataRowCount());
     }
 
-
     public function testGetTotalRowCountSingleEnclosure() {
         $this->csv->heading = false;
         $this->csv->enclosure = "'";
@@ -73,4 +72,11 @@ class DataRowCountTest extends TestCase {
         $this->assertEquals(3, $this->csv->getTotalDataRowCount());
     }
 
+    public function testGetTotalRowCountSingleRow() {
+        $this->csv->heading = false;
+        $this->csv->enclosure = "'";
+        $sInput = "86545235689";
+        $this->csv->load_data($sInput);
+        $this->assertEquals(1, $this->csv->getTotalDataRowCount());
+    }
 }
diff --git a/tests/methods/OutputTest.php b/tests/methods/OutputTest.php
new file mode 100644
index 0000000..f323411
--- /dev/null
+++ b/tests/methods/OutputTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace ParseCsv\tests\methods;
+
+use ParseCsv\Csv;
+use PHPUnit\Framework\TestCase;
+
+class OutputTest extends TestCase {
+
+    /**
+     * @runInSeparateProcess because download.php uses header()
+     */
+    public function testOutputWithFourParameters() {
+        $csv = new Csv();
+        $data = [0 => ['a', 'b', 'c'], 1 => ['d', 'e', 'f']];
+        $fields = ['col1', 'col2', 'col3'];
+        $output = $csv->output('test.csv', $data, $fields, ',');
+        $expected = "col1,col2,col3\ra,b,c\rd,e,f\r";
+        self::assertEquals($expected, $output);
+    }
+}