diff --git a/CHANGELOG.md b/CHANGELOG.md
index dd66498f19..05d4e19b6c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -39,7 +39,7 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 
 ### Changed
 
-- Nothing
+- `toFormattedString` will now always return a string. This can affect the results of `toArray`, `namedRangeToArray`, and `rangeToArray`. [PR #3304](https://github.com/PHPOffice/PhpSpreadsheet/pull/3304)
 
 ### Deprecated
 
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index f40d8b8ed0..6902498f96 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -790,56 +790,6 @@ parameters:
 			count: 1
 			path: src/PhpSpreadsheet/Shared/Trend/Trend.php
 
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Style\\\\NumberFormat\\\\Formatter\\:\\:splitFormat\\(\\) has no return type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Style/NumberFormat/Formatter.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Style\\\\NumberFormat\\\\Formatter\\:\\:splitFormat\\(\\) has parameter \\$sections with no type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Style/NumberFormat/Formatter.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Style\\\\NumberFormat\\\\Formatter\\:\\:splitFormat\\(\\) has parameter \\$value with no type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Style/NumberFormat/Formatter.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Style\\\\NumberFormat\\\\Formatter\\:\\:splitFormatCompare\\(\\) has no return type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Style/NumberFormat/Formatter.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Style\\\\NumberFormat\\\\Formatter\\:\\:splitFormatCompare\\(\\) has parameter \\$cond with no type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Style/NumberFormat/Formatter.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Style\\\\NumberFormat\\\\Formatter\\:\\:splitFormatCompare\\(\\) has parameter \\$dfcond with no type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Style/NumberFormat/Formatter.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Style\\\\NumberFormat\\\\Formatter\\:\\:splitFormatCompare\\(\\) has parameter \\$dfval with no type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Style/NumberFormat/Formatter.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Style\\\\NumberFormat\\\\Formatter\\:\\:splitFormatCompare\\(\\) has parameter \\$val with no type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Style/NumberFormat/Formatter.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Style\\\\NumberFormat\\\\Formatter\\:\\:splitFormatCompare\\(\\) has parameter \\$value with no type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Style/NumberFormat/Formatter.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Style\\\\NumberFormat\\\\Formatter\\:\\:toFormattedString\\(\\) should return string but returns float\\|int\\|string\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Style/NumberFormat/Formatter.php
-
 		-
 			message: "#^Negated boolean expression is always false\\.$#"
 			count: 1
diff --git a/src/PhpSpreadsheet/Style/NumberFormat/Formatter.php b/src/PhpSpreadsheet/Style/NumberFormat/Formatter.php
index be195a8803..03b002e533 100644
--- a/src/PhpSpreadsheet/Style/NumberFormat/Formatter.php
+++ b/src/PhpSpreadsheet/Style/NumberFormat/Formatter.php
@@ -2,12 +2,19 @@
 
 namespace PhpOffice\PhpSpreadsheet\Style\NumberFormat;
 
+use PhpOffice\PhpSpreadsheet\Calculation\Calculation;
+use PhpOffice\PhpSpreadsheet\RichText\RichText;
 use PhpOffice\PhpSpreadsheet\Style\Color;
 use PhpOffice\PhpSpreadsheet\Style\NumberFormat;
 
 class Formatter
 {
-    private static function splitFormatCompare($value, $cond, $val, $dfcond, $dfval)
+    /**
+     * @param mixed $value
+     * @param mixed $val
+     * @param mixed $dfval
+     */
+    private static function splitFormatCompare($value, ?string $cond, $val, string $dfcond, $dfval): bool
     {
         if (!$cond) {
             $cond = $dfcond;
@@ -33,7 +40,8 @@ private static function splitFormatCompare($value, $cond, $val, $dfcond, $dfval)
         return $value >= $val;
     }
 
-    private static function splitFormat($sections, $value)
+    /** @param mixed $value */
+    private static function splitFormat(array $sections, $value): array
     {
         // Extract the relevant section depending on whether number is positive, negative, or zero?
         // Text not supported yet.
@@ -93,7 +101,7 @@ private static function splitFormat($sections, $value)
     /**
      * Convert a value in a pre-defined format to a PHP string.
      *
-     * @param mixed $value Value to format
+     * @param null|bool|float|int|RichText|string $value Value to format
      * @param string $format Format code, see = NumberFormat::FORMAT_*
      * @param array $callBack Callback function for additional formatting of string
      *
@@ -101,15 +109,18 @@ private static function splitFormat($sections, $value)
      */
     public static function toFormattedString($value, $format, $callBack = null)
     {
+        if (is_bool($value)) {
+            return $value ? Calculation::getTRUE() : Calculation::getFALSE();
+        }
         // For now we do not treat strings although section 4 of a format code affects strings
         if (!is_numeric($value)) {
-            return $value;
+            return (string) $value;
         }
 
         // For 'General' format code, we just pass the value although this is not entirely the way Excel does it,
         // it seems to round numbers to a total of 10 digits.
         if (($format === NumberFormat::FORMAT_GENERAL) || ($format === NumberFormat::FORMAT_TEXT)) {
-            return $value;
+            return (string) $value;
         }
 
         // Ignore square-$-brackets prefix in format string, like "[$-411]ge.m.d", "[$-010419]0%", etc
@@ -127,7 +138,7 @@ function ($matches) {
         $format = (string) preg_replace('/(\\\(((.)(?!((AM\/PM)|(A\/P))))|([^ ])))(?=(?:[^"]|"[^"]*")*$)/ui', '"${2}"', $format);
 
         // Get the sections, there can be up to four sections, separated with a semi-colon (but only if not a quoted literal)
-        $sections = preg_split('/(;)(?=(?:[^"]|"[^"]*")*$)/u', $format);
+        $sections = preg_split('/(;)(?=(?:[^"]|"[^"]*")*$)/u', $format) ?: [];
 
         [$colors, $format, $value] = self::splitFormat($sections, $value);
 
@@ -145,8 +156,8 @@ function ($matches) {
             if (substr($format, 0, 1) === '"' && substr($format, -1, 1) === '"' && substr_count($format, '"') === 2) {
                 $value = substr($format, 1, -1);
             } elseif (preg_match('/[0#, ]%/', $format)) {
-                // % number format
-                $value = PercentageFormatter::format($value, $format);
+                // % number format - avoid weird '-0' problem
+                $value = PercentageFormatter::format(0 + (float) $value, $format);
             } else {
                 $value = NumberFormatter::format($value, $format);
             }
diff --git a/tests/PhpSpreadsheetTests/Reader/Ods/HiddenMergeCellsTest.php b/tests/PhpSpreadsheetTests/Reader/Ods/HiddenMergeCellsTest.php
index 710b292afd..3f38631c47 100644
--- a/tests/PhpSpreadsheetTests/Reader/Ods/HiddenMergeCellsTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Ods/HiddenMergeCellsTest.php
@@ -3,46 +3,43 @@
 namespace PhpOffice\PhpSpreadsheetTests\Reader\Ods;
 
 use PhpOffice\PhpSpreadsheet\Reader\Ods;
-use PhpOffice\PhpSpreadsheet\Spreadsheet;
 use PHPUnit\Framework\TestCase;
 
 class HiddenMergeCellsTest extends TestCase
 {
-    /**
-     * @var Spreadsheet
-     */
-    private $spreadsheet;
-
-    protected function setup(): void
-    {
-        $filename = 'tests/data/Reader/Ods/HiddenMergeCellsTest.ods';
-        $reader = new Ods();
-        $this->spreadsheet = $reader->load($filename);
-    }
+    private const FILENAME = 'tests/data/Reader/Ods/HiddenMergeCellsTest.ods';
 
     public function testHiddenMergeCells(): void
     {
-        $c2InMergeRange = $this->spreadsheet->getActiveSheet()->getCell('C2')->isInMergeRange();
+        $reader = new Ods();
+        $spreadsheet = $reader->load(self::FILENAME);
+        $c2InMergeRange = $spreadsheet->getActiveSheet()->getCell('C2')->isInMergeRange();
         self::assertTrue($c2InMergeRange);
-        $a2InMergeRange = $this->spreadsheet->getActiveSheet()->getCell('A2')->isInMergeRange();
+        $a2InMergeRange = $spreadsheet->getActiveSheet()->getCell('A2')->isInMergeRange();
         self::assertTrue($a2InMergeRange);
-        $a2MergeRangeValue = $this->spreadsheet->getActiveSheet()->getCell('A2')->isMergeRangeValueCell();
+        $a2MergeRangeValue = $spreadsheet->getActiveSheet()->getCell('A2')->isMergeRangeValueCell();
         self::assertTrue($a2MergeRangeValue);
 
-        $cellArray = $this->spreadsheet->getActiveSheet()->rangeToArray('A2:C2');
+        $cellArray = $spreadsheet->getActiveSheet()->rangeToArray('A2:C2');
+        self::assertSame([['12', '4', '3']], $cellArray);
+        $cellArray = $spreadsheet->getActiveSheet()->rangeToArray('A2:C2', null, true, false);
         self::assertSame([[12, 4, 3]], $cellArray);
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testUnmergeHiddenMergeCells(): void
     {
-        $this->spreadsheet->getActiveSheet()->unmergeCells('A2:C2');
+        $reader = new Ods();
+        $spreadsheet = $reader->load(self::FILENAME);
+        $spreadsheet->getActiveSheet()->unmergeCells('A2:C2');
 
-        $c2InMergeRange = $this->spreadsheet->getActiveSheet()->getCell('C2')->isInMergeRange();
+        $c2InMergeRange = $spreadsheet->getActiveSheet()->getCell('C2')->isInMergeRange();
         self::assertFalse($c2InMergeRange);
-        $a2InMergeRange = $this->spreadsheet->getActiveSheet()->getCell('A2')->isInMergeRange();
+        $a2InMergeRange = $spreadsheet->getActiveSheet()->getCell('A2')->isInMergeRange();
         self::assertFalse($a2InMergeRange);
 
-        $cellArray = $this->spreadsheet->getActiveSheet()->rangeToArray('A2:C2', null, false, false, false);
+        $cellArray = $spreadsheet->getActiveSheet()->rangeToArray('A2:C2', null, false, false, false);
         self::assertSame([[12, '=6-B1', '=A2/B2']], $cellArray);
+        $spreadsheet->disconnectWorksheets();
     }
 }
diff --git a/tests/PhpSpreadsheetTests/Reader/Ods/HiddenWorksheetTest.php b/tests/PhpSpreadsheetTests/Reader/Ods/HiddenWorksheetTest.php
index c02c877128..5a0753d181 100644
--- a/tests/PhpSpreadsheetTests/Reader/Ods/HiddenWorksheetTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Ods/HiddenWorksheetTest.php
@@ -3,29 +3,19 @@
 namespace PhpOffice\PhpSpreadsheetTests\Reader\Ods;
 
 use PhpOffice\PhpSpreadsheet\Reader\Ods;
-use PhpOffice\PhpSpreadsheet\Spreadsheet;
 use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;
 use PHPUnit\Framework\TestCase;
 
 class HiddenWorksheetTest extends TestCase
 {
-    /**
-     * @var Spreadsheet
-     */
-    private $spreadsheet;
-
-    protected function setup(): void
+    public function testPageSetup(): void
     {
         $filename = 'tests/data/Reader/Ods/HiddenSheet.ods';
         $reader = new Ods();
-        $this->spreadsheet = $reader->load($filename);
-    }
-
-    public function testPageSetup(): void
-    {
+        $spreadsheet = $reader->load($filename);
         $assertions = $this->worksheetAssertions();
 
-        foreach ($this->spreadsheet->getAllSheets() as $worksheet) {
+        foreach ($spreadsheet->getAllSheets() as $worksheet) {
             if (!array_key_exists($worksheet->getTitle(), $assertions)) {
                 continue;
             }
@@ -40,6 +30,7 @@ public function testPageSetup(): void
                 );
             }
         }
+        $spreadsheet->disconnectWorksheets();
     }
 
     private function worksheetAssertions(): array
diff --git a/tests/PhpSpreadsheetTests/Reader/Xls/HiddenMergeCellsTest.php b/tests/PhpSpreadsheetTests/Reader/Xls/HiddenMergeCellsTest.php
index c70852819e..0a59b7d447 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xls/HiddenMergeCellsTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Xls/HiddenMergeCellsTest.php
@@ -3,46 +3,43 @@
 namespace PhpOffice\PhpSpreadsheetTests\Reader\Xls;
 
 use PhpOffice\PhpSpreadsheet\Reader\Xls;
-use PhpOffice\PhpSpreadsheet\Spreadsheet;
 use PHPUnit\Framework\TestCase;
 
 class HiddenMergeCellsTest extends TestCase
 {
-    /**
-     * @var Spreadsheet
-     */
-    private $spreadsheet;
-
-    protected function setup(): void
-    {
-        $filename = 'tests/data/Reader/XLS/HiddenMergeCellsTest.xls';
-        $reader = new Xls();
-        $this->spreadsheet = $reader->load($filename);
-    }
+    private const FILENAME = 'tests/data/Reader/XLS/HiddenMergeCellsTest.xls';
 
     public function testHiddenMergeCells(): void
     {
-        $c2InMergeRange = $this->spreadsheet->getActiveSheet()->getCell('C2')->isInMergeRange();
+        $reader = new Xls();
+        $spreadsheet = $reader->load(self::FILENAME);
+        $c2InMergeRange = $spreadsheet->getActiveSheet()->getCell('C2')->isInMergeRange();
         self::assertTrue($c2InMergeRange);
-        $a2InMergeRange = $this->spreadsheet->getActiveSheet()->getCell('A2')->isInMergeRange();
+        $a2InMergeRange = $spreadsheet->getActiveSheet()->getCell('A2')->isInMergeRange();
         self::assertTrue($a2InMergeRange);
-        $a2MergeRangeValue = $this->spreadsheet->getActiveSheet()->getCell('A2')->isMergeRangeValueCell();
+        $a2MergeRangeValue = $spreadsheet->getActiveSheet()->getCell('A2')->isMergeRangeValueCell();
         self::assertTrue($a2MergeRangeValue);
 
-        $cellArray = $this->spreadsheet->getActiveSheet()->rangeToArray('A2:C2');
+        $cellArray = $spreadsheet->getActiveSheet()->rangeToArray('A2:C2');
+        self::assertSame([['12', '4', '3']], $cellArray);
+        $cellArray = $spreadsheet->getActiveSheet()->rangeToArray('A2:C2', null, true, false);
         self::assertSame([[12, 4, 3]], $cellArray);
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testUnmergeHiddenMergeCells(): void
     {
-        $this->spreadsheet->getActiveSheet()->unmergeCells('A2:C2');
+        $reader = new Xls();
+        $spreadsheet = $reader->load(self::FILENAME);
+        $spreadsheet->getActiveSheet()->unmergeCells('A2:C2');
 
-        $c2InMergeRange = $this->spreadsheet->getActiveSheet()->getCell('C2')->isInMergeRange();
+        $c2InMergeRange = $spreadsheet->getActiveSheet()->getCell('C2')->isInMergeRange();
         self::assertFalse($c2InMergeRange);
-        $a2InMergeRange = $this->spreadsheet->getActiveSheet()->getCell('A2')->isInMergeRange();
+        $a2InMergeRange = $spreadsheet->getActiveSheet()->getCell('A2')->isInMergeRange();
         self::assertFalse($a2InMergeRange);
 
-        $cellArray = $this->spreadsheet->getActiveSheet()->rangeToArray('A2:C2', null, false, false, false);
+        $cellArray = $spreadsheet->getActiveSheet()->rangeToArray('A2:C2', null, false, false, false);
         self::assertSame([[12, '=6-B1', '=A2/B2']], $cellArray);
+        $spreadsheet->disconnectWorksheets();
     }
 }
diff --git a/tests/PhpSpreadsheetTests/Reader/Xls/HiddenWorksheetTest.php b/tests/PhpSpreadsheetTests/Reader/Xls/HiddenWorksheetTest.php
index 82fd6e128e..e31b388049 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xls/HiddenWorksheetTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Xls/HiddenWorksheetTest.php
@@ -3,29 +3,19 @@
 namespace PhpOffice\PhpSpreadsheetTests\Reader\Xls;
 
 use PhpOffice\PhpSpreadsheet\Reader\Xls;
-use PhpOffice\PhpSpreadsheet\Spreadsheet;
 use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;
 use PHPUnit\Framework\TestCase;
 
 class HiddenWorksheetTest extends TestCase
 {
-    /**
-     * @var Spreadsheet
-     */
-    private $spreadsheet;
-
-    protected function setup(): void
+    public function testPageSetup(): void
     {
         $filename = 'tests/data/Reader/XLS/HiddenSheet.xls';
         $reader = new Xls();
-        $this->spreadsheet = $reader->load($filename);
-    }
-
-    public function testPageSetup(): void
-    {
+        $spreadsheet = $reader->load($filename);
         $assertions = $this->worksheetAssertions();
 
-        foreach ($this->spreadsheet->getAllSheets() as $worksheet) {
+        foreach ($spreadsheet->getAllSheets() as $worksheet) {
             if (!array_key_exists($worksheet->getTitle(), $assertions)) {
                 continue;
             }
@@ -40,6 +30,7 @@ public function testPageSetup(): void
                 );
             }
         }
+        $spreadsheet->disconnectWorksheets();
     }
 
     private function worksheetAssertions(): array
diff --git a/tests/PhpSpreadsheetTests/Reader/Xls/NumberFormatGeneralTest.php b/tests/PhpSpreadsheetTests/Reader/Xls/NumberFormatGeneralTest.php
index 8086789232..3bfea8bf22 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xls/NumberFormatGeneralTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Xls/NumberFormatGeneralTest.php
@@ -21,7 +21,7 @@ public function testGeneral(): void
         self::assertSame(2.95, $sheet->getCell('D2')->getValue());
         self::assertSame(2.95, $sheet->getCell('D2')->getCalculatedValue());
         self::assertSame('€ 2.95', $sheet->getCell('D2')->getFormattedValue());
-        self::assertSame(21, $array[1][4]);
+        self::assertSame('21', $array[1][4]);
         self::assertSame(21, $sheet->getCell('E2')->getValue());
         self::assertSame(21, $sheet->getCell('E2')->getCalculatedValue());
         self::assertSame('21', $sheet->getCell('E2')->getFormattedValue());
diff --git a/tests/PhpSpreadsheetTests/Reader/Xlsx/HiddenMergeCellsTest.php b/tests/PhpSpreadsheetTests/Reader/Xlsx/HiddenMergeCellsTest.php
index 4919cd272c..9d4fc81808 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xlsx/HiddenMergeCellsTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Xlsx/HiddenMergeCellsTest.php
@@ -3,46 +3,43 @@
 namespace PhpOffice\PhpSpreadsheetTests\Reader\Xlsx;
 
 use PhpOffice\PhpSpreadsheet\Reader\Xlsx;
-use PhpOffice\PhpSpreadsheet\Spreadsheet;
 use PHPUnit\Framework\TestCase;
 
 class HiddenMergeCellsTest extends TestCase
 {
-    /**
-     * @var Spreadsheet
-     */
-    private $spreadsheet;
-
-    protected function setup(): void
-    {
-        $filename = 'tests/data/Reader/XLSX/HiddenMergeCellsTest.xlsx';
-        $reader = new Xlsx();
-        $this->spreadsheet = $reader->load($filename);
-    }
+    private const FILENAME = 'tests/data/Reader/XLSX/HiddenMergeCellsTest.xlsx';
 
     public function testHiddenMergeCells(): void
     {
-        $c2InMergeRange = $this->spreadsheet->getActiveSheet()->getCell('C2')->isInMergeRange();
+        $reader = new Xlsx();
+        $spreadsheet = $reader->load(self::FILENAME);
+        $c2InMergeRange = $spreadsheet->getActiveSheet()->getCell('C2')->isInMergeRange();
         self::assertTrue($c2InMergeRange);
-        $a2InMergeRange = $this->spreadsheet->getActiveSheet()->getCell('A2')->isInMergeRange();
+        $a2InMergeRange = $spreadsheet->getActiveSheet()->getCell('A2')->isInMergeRange();
         self::assertTrue($a2InMergeRange);
-        $a2MergeRangeValue = $this->spreadsheet->getActiveSheet()->getCell('A2')->isMergeRangeValueCell();
+        $a2MergeRangeValue = $spreadsheet->getActiveSheet()->getCell('A2')->isMergeRangeValueCell();
         self::assertTrue($a2MergeRangeValue);
 
-        $cellArray = $this->spreadsheet->getActiveSheet()->rangeToArray('A2:C2');
+        $cellArray = $spreadsheet->getActiveSheet()->rangeToArray('A2:C2');
+        self::assertSame([['12', '4', '3']], $cellArray);
+        $cellArray = $spreadsheet->getActiveSheet()->rangeToArray('A2:C2', null, true, false);
         self::assertSame([[12, 4, 3]], $cellArray);
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testUnmergeHiddenMergeCells(): void
     {
-        $this->spreadsheet->getActiveSheet()->unmergeCells('A2:C2');
+        $reader = new Xlsx();
+        $spreadsheet = $reader->load(self::FILENAME);
+        $spreadsheet->getActiveSheet()->unmergeCells('A2:C2');
 
-        $c2InMergeRange = $this->spreadsheet->getActiveSheet()->getCell('C2')->isInMergeRange();
+        $c2InMergeRange = $spreadsheet->getActiveSheet()->getCell('C2')->isInMergeRange();
         self::assertFalse($c2InMergeRange);
-        $a2InMergeRange = $this->spreadsheet->getActiveSheet()->getCell('A2')->isInMergeRange();
+        $a2InMergeRange = $spreadsheet->getActiveSheet()->getCell('A2')->isInMergeRange();
         self::assertFalse($a2InMergeRange);
 
-        $cellArray = $this->spreadsheet->getActiveSheet()->rangeToArray('A2:C2', null, false, false, false);
+        $cellArray = $spreadsheet->getActiveSheet()->rangeToArray('A2:C2', null, false, false, false);
         self::assertSame([[12, '=6-B1', '=A2/B2']], $cellArray);
+        $spreadsheet->disconnectWorksheets();
     }
 }
diff --git a/tests/PhpSpreadsheetTests/Reader/Xlsx/HiddenWorksheetTest.php b/tests/PhpSpreadsheetTests/Reader/Xlsx/HiddenWorksheetTest.php
index 130d76a642..e11954eb51 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xlsx/HiddenWorksheetTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Xlsx/HiddenWorksheetTest.php
@@ -3,29 +3,19 @@
 namespace PhpOffice\PhpSpreadsheetTests\Reader\Xlsx;
 
 use PhpOffice\PhpSpreadsheet\Reader\Xlsx;
-use PhpOffice\PhpSpreadsheet\Spreadsheet;
 use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;
 use PHPUnit\Framework\TestCase;
 
 class HiddenWorksheetTest extends TestCase
 {
-    /**
-     * @var Spreadsheet
-     */
-    private $spreadsheet;
-
-    protected function setup(): void
+    public function testPageSetup(): void
     {
         $filename = 'tests/data/Reader/XLSX/HiddenSheet.xlsx';
         $reader = new Xlsx();
-        $this->spreadsheet = $reader->load($filename);
-    }
-
-    public function testPageSetup(): void
-    {
+        $spreadsheet = $reader->load($filename);
         $assertions = $this->worksheetAssertions();
 
-        foreach ($this->spreadsheet->getAllSheets() as $worksheet) {
+        foreach ($spreadsheet->getAllSheets() as $worksheet) {
             if (!array_key_exists($worksheet->getTitle(), $assertions)) {
                 continue;
             }
@@ -40,6 +30,7 @@ public function testPageSetup(): void
                 );
             }
         }
+        $spreadsheet->disconnectWorksheets();
     }
 
     private function worksheetAssertions(): array
diff --git a/tests/PhpSpreadsheetTests/Reader/Xlsx/Issue2488Test.php b/tests/PhpSpreadsheetTests/Reader/Xlsx/Issue2488Test.php
index 805b6ff591..9b77df4efd 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xlsx/Issue2488Test.php
+++ b/tests/PhpSpreadsheetTests/Reader/Xlsx/Issue2488Test.php
@@ -28,7 +28,7 @@ public function testPreliminaries(): void
         }
     }
 
-    public function testIssue2450(): void
+    public function testIssue2488(): void
     {
         // Cell explicitly typed as numeric but without value.
         $filename = self::$testbook;
@@ -38,12 +38,24 @@ public function testIssue2450(): void
         // E1 and D3 are numeric/boolean without value.
         // So is E2, but I don't see a practical difference
         //    between null string and null in that case.
+        $expected = [
+            ['1', '2', '3', '0', null, '-1', '-2', '-3'],
+            ['a', 'b', 'c', 'xxx', '', 'd', 'e', 'f'],
+            ['FALSE', 'FALSE', 'FALSE', null, 'TRUE', 'TRUE', 'TRUE', 'TRUE'],
+        ];
+        self::assertSame($expected, $sheet->toArray());
+        $expected = [
+            ['1', '2', '3', '0', '', '-1', '-2', '-3'],
+            ['a', 'b', 'c', 'xxx', '', 'd', 'e', 'f'],
+            ['FALSE', 'FALSE', 'FALSE', '', 'TRUE', 'TRUE', 'TRUE', 'TRUE'],
+        ];
+        self::assertSame($expected, $sheet->toArray(''));
         $expected = [
             [1, 2, 3, 0, null, -1, -2, -3],
             ['a', 'b', 'c', 'xxx', '', 'd', 'e', 'f'],
             [false, false, false, null, true, true, true, true],
         ];
-        self::assertSame($expected, $sheet->toArray());
+        self::assertSame($expected, $sheet->toArray(null, true, false));
 
         $spreadsheet->disconnectWorksheets();
     }
diff --git a/tests/PhpSpreadsheetTests/RichTextTest.php b/tests/PhpSpreadsheetTests/RichTextTest.php
index e6f5551478..04a1d72a9e 100644
--- a/tests/PhpSpreadsheetTests/RichTextTest.php
+++ b/tests/PhpSpreadsheetTests/RichTextTest.php
@@ -36,5 +36,14 @@ public function testTextElements(): void
         $cloneText = clone $richText;
         self::assertEquals($richText, $cloneText);
         self::assertNotSame($richText, $cloneText);
+
+        $spreadsheet = new Spreadsheet();
+        $sheet = $spreadsheet->getActiveSheet();
+        $sheet->getCell('A1')->setValue($richText);
+        self::assertInstanceOf(RichText::class, $sheet->getCell('A1')->getValue());
+        self::assertSame('ABC', $sheet->getCell('A1')->getFormattedValue());
+        $sheet->getCell('B1')->setValue(-3.5);
+        self::assertSame([['ABC', '-3.5']], $sheet->toArray());
+        $spreadsheet->disconnectWorksheets();
     }
 }
diff --git a/tests/PhpSpreadsheetTests/Worksheet/MergeBehaviourTest.php b/tests/PhpSpreadsheetTests/Worksheet/MergeBehaviourTest.php
index 68c9d87a8e..7d7a2c8366 100644
--- a/tests/PhpSpreadsheetTests/Worksheet/MergeBehaviourTest.php
+++ b/tests/PhpSpreadsheetTests/Worksheet/MergeBehaviourTest.php
@@ -38,8 +38,9 @@ public function testMergeCellsDefaultBehaviour(): void
         $worksheet->fromArray($this->testDataRaw, null, 'A1', true);
         $worksheet->mergeCells($mergeRange);
 
-        $mergeResult = $worksheet->toArray(null, true, true, false);
+        $mergeResult = $worksheet->toArray(null, true, false, false);
         self::assertSame($expectedResult, $mergeResult);
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testMergeCellsDefaultBehaviourFormatted(): void
@@ -57,6 +58,7 @@ public function testMergeCellsDefaultBehaviourFormatted(): void
 
         $mergeResult = $worksheet->toArray(null, true, true, false);
         self::assertSame($expectedResult, $mergeResult);
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testMergeCellsHideBehaviour(): void
@@ -73,8 +75,9 @@ public function testMergeCellsHideBehaviour(): void
         $worksheet->fromArray($this->testDataRaw, null, 'A1', true);
         $worksheet->mergeCells($mergeRange, Worksheet::MERGE_CELL_CONTENT_HIDE);
 
-        $mergeResult = $worksheet->toArray(null, true, true, false);
+        $mergeResult = $worksheet->toArray(null, true, false, false);
         self::assertSame($expectedResult, $mergeResult);
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testMergeCellsHideBehaviourFormatted(): void
@@ -92,6 +95,7 @@ public function testMergeCellsHideBehaviourFormatted(): void
 
         $mergeResult = $worksheet->toArray(null, true, true, false);
         self::assertSame($expectedResult, $mergeResult);
+        $spreadsheet->disconnectWorksheets();
     }
 
     /**
@@ -108,6 +112,7 @@ public function testMergeCellsMergeBehaviour(array $testData, string $mergeRange
 
         $mergeResult = $worksheet->toArray(null, true, true, false);
         self::assertSame($expectedResult, $mergeResult);
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function mergeCellsMergeBehaviourProvider(): array
@@ -162,5 +167,6 @@ public function testMergeCellsMergeBehaviourFormatted(): void
 
         $mergeResult = $worksheet->toArray(null, true, true, false);
         self::assertSame($expectedResult, $mergeResult);
+        $spreadsheet->disconnectWorksheets();
     }
 }
diff --git a/tests/PhpSpreadsheetTests/Worksheet/WorksheetNamedRangesTest.php b/tests/PhpSpreadsheetTests/Worksheet/WorksheetNamedRangesTest.php
index 506e753c4e..3b7f64c577 100644
--- a/tests/PhpSpreadsheetTests/Worksheet/WorksheetNamedRangesTest.php
+++ b/tests/PhpSpreadsheetTests/Worksheet/WorksheetNamedRangesTest.php
@@ -9,154 +9,180 @@
 
 class WorksheetNamedRangesTest extends TestCase
 {
-    /**
-     * @var Spreadsheet
-     */
-    private $spreadsheet;
-
-    protected function setUp(): void
+    protected function getSpreadsheet(): Spreadsheet
     {
         $reader = new Xlsx();
-        $this->spreadsheet = $reader->load('tests/data/Worksheet/namedRangeTest.xlsx');
+
+        return $reader->load('tests/data/Worksheet/namedRangeTest.xlsx');
     }
 
     public function testCellExists(): void
     {
+        $spreadsheet = $this->getSpreadsheet();
         $namedCell = 'GREETING';
 
-        $worksheet = $this->spreadsheet->getActiveSheet();
+        $worksheet = $spreadsheet->getActiveSheet();
         $cellExists = $worksheet->cellExists($namedCell);
         self::assertTrue($cellExists);
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testCellExistsUtf8(): void
     {
+        $spreadsheet = $this->getSpreadsheet();
         $namedCell = 'Χαιρετισμός';
 
-        $worksheet = $this->spreadsheet->getActiveSheet();
+        $worksheet = $spreadsheet->getActiveSheet();
         $cellExists = $worksheet->cellExists($namedCell);
         self::assertTrue($cellExists);
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testCellNotExists(): void
     {
+        $spreadsheet = $this->getSpreadsheet();
         $namedCell = 'GOODBYE';
 
-        $worksheet = $this->spreadsheet->getActiveSheet();
+        $worksheet = $spreadsheet->getActiveSheet();
         $cellExists = $worksheet->cellExists($namedCell);
         self::assertFalse($cellExists);
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testCellExistsInvalidScope(): void
     {
+        $spreadsheet = $this->getSpreadsheet();
         $namedCell = 'Result';
 
-        $worksheet = $this->spreadsheet->getActiveSheet();
+        $worksheet = $spreadsheet->getActiveSheet();
         $cellExists = $worksheet->cellExists($namedCell);
         self::assertFalse($cellExists);
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testCellExistsRange(): void
     {
+        $spreadsheet = $this->getSpreadsheet();
         $namedRange = 'Range1';
 
         $this->expectException(Exception::class);
         $this->expectExceptionMessage('Cell coordinate string can not be a range of cells');
 
-        $worksheet = $this->spreadsheet->getActiveSheet();
+        $worksheet = $spreadsheet->getActiveSheet();
         $worksheet->cellExists($namedRange);
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testGetCell(): void
     {
+        $spreadsheet = $this->getSpreadsheet();
         $namedCell = 'GREETING';
 
-        $worksheet = $this->spreadsheet->getActiveSheet();
+        $worksheet = $spreadsheet->getActiveSheet();
         $cell = $worksheet->getCell($namedCell);
         self::assertSame('Hello', $cell->getValue());
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testGetCellUtf8(): void
     {
+        $spreadsheet = $this->getSpreadsheet();
         $namedCell = 'Χαιρετισμός';
 
-        $worksheet = $this->spreadsheet->getActiveSheet();
+        $worksheet = $spreadsheet->getActiveSheet();
         $cell = $worksheet->getCell($namedCell);
         self::assertSame('नमस्ते', $cell->getValue());
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testGetCellNotExists(): void
     {
+        $spreadsheet = $this->getSpreadsheet();
         $namedCell = 'GOODBYE';
 
         $this->expectException(Exception::class);
         $this->expectExceptionMessage("Invalid cell coordinate {$namedCell}");
 
-        $worksheet = $this->spreadsheet->getActiveSheet();
+        $worksheet = $spreadsheet->getActiveSheet();
         $worksheet->getCell($namedCell);
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testGetCellInvalidScope(): void
     {
+        $spreadsheet = $this->getSpreadsheet();
         $namedCell = 'Result';
         $ucNamedCell = strtoupper($namedCell);
 
         $this->expectException(Exception::class);
         $this->expectExceptionMessage("Invalid cell coordinate {$ucNamedCell}");
 
-        $worksheet = $this->spreadsheet->getActiveSheet();
+        $worksheet = $spreadsheet->getActiveSheet();
         $worksheet->getCell($namedCell);
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testGetCellLocalScoped(): void
     {
+        $spreadsheet = $this->getSpreadsheet();
         $namedCell = 'Result';
 
-        $this->spreadsheet->setActiveSheetIndexByName('Sheet2');
-        $worksheet = $this->spreadsheet->getActiveSheet();
+        $spreadsheet->setActiveSheetIndexByName('Sheet2');
+        $worksheet = $spreadsheet->getActiveSheet();
         $cell = $worksheet->getCell($namedCell);
         self::assertSame(8, $cell->getCalculatedValue());
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testGetCellNamedFormula(): void
     {
+        $spreadsheet = $this->getSpreadsheet();
         $namedCell = 'Result';
 
-        $this->spreadsheet->setActiveSheetIndexByName('Sheet2');
-        $worksheet = $this->spreadsheet->getActiveSheet();
+        $spreadsheet->setActiveSheetIndexByName('Sheet2');
+        $worksheet = $spreadsheet->getActiveSheet();
         $cell = $worksheet->getCell($namedCell);
         self::assertSame(8, $cell->getCalculatedValue());
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testGetCellWithNamedRange(): void
     {
+        $spreadsheet = $this->getSpreadsheet();
         $namedCell = 'Range1';
 
         $this->expectException(Exception::class);
         $this->expectExceptionMessage('Cell coordinate string can not be a range of cells');
 
-        $worksheet = $this->spreadsheet->getActiveSheet();
+        $worksheet = $spreadsheet->getActiveSheet();
         $worksheet->getCell($namedCell);
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testNamedRangeToArray(): void
     {
+        $spreadsheet = $this->getSpreadsheet();
         $namedRange = 'Range1';
 
-        $worksheet = $this->spreadsheet->getActiveSheet();
+        $worksheet = $spreadsheet->getActiveSheet();
         $rangeData = $worksheet->namedRangeToArray($namedRange);
+        self::assertSame([['1', '2', '3']], $rangeData);
+        $rangeData = $worksheet->namedRangeToArray($namedRange, null, true, false);
         self::assertSame([[1, 2, 3]], $rangeData);
+        $spreadsheet->disconnectWorksheets();
     }
 
     public function testInvalidNamedRangeToArray(): void
     {
+        $spreadsheet = $this->getSpreadsheet();
         $namedRange = 'Range2';
 
         $this->expectException(Exception::class);
         $this->expectExceptionMessage("Named Range {$namedRange} does not exist");
 
-        $worksheet = $this->spreadsheet->getActiveSheet();
+        $worksheet = $spreadsheet->getActiveSheet();
         $rangeData = $worksheet->namedRangeToArray($namedRange);
         self::assertSame([[1, 2, 3]], $rangeData);
+        $spreadsheet->disconnectWorksheets();
     }
 }