diff --git a/composer.json b/composer.json
index a45828d..edf200e 100644
--- a/composer.json
+++ b/composer.json
@@ -32,10 +32,7 @@
         "avadim/fast-excel-writer": "^4.8",
         "avadim/fast-excel-reader": "^2.11"
     },
-    "funding": [
-        {
-            "type": "other",
-            "url": "https://www.paypal.me/VShemarov"
-        }
-    ]
+    "require-dev": {
+        "phpunit/phpunit": "^9.0"
+    }
 }
diff --git a/src/FastExcelTemplator/ExcelWriter.php b/src/FastExcelTemplator/ExcelWriter.php
index 4f6a5ed..f4a960a 100644
--- a/src/FastExcelTemplator/ExcelWriter.php
+++ b/src/FastExcelTemplator/ExcelWriter.php
@@ -29,7 +29,11 @@ public function makeSheet(string $sheetName = null): SheetWriter
      */
     public function replaceSheets($inputFile, $outputFile): bool
     {
-        $result = $this->writer->_replaceSheets($inputFile, $outputFile);
+        $relationShips = [
+            'rel_id' => ['workbook' => 0],
+        ];
+
+        $result = $this->writer->_replaceSheets($inputFile, $outputFile, $relationShips);
         if ($result) {
             $zip = new \ZipArchive();
             if (!$zip->open($outputFile)) {
diff --git a/src/FastExcelTemplator/RowTemplate.php b/src/FastExcelTemplator/RowTemplate.php
index e73611f..76ad547 100644
--- a/src/FastExcelTemplator/RowTemplate.php
+++ b/src/FastExcelTemplator/RowTemplate.php
@@ -68,24 +68,30 @@ public function attribute($name): ?string
         return $this->attributes[$name] ?? null;
     }
 
+    #[\ReturnTypeWillChange]
     public function current()
     {
         return current($this->domCells);
     }
 
+    #[\ReturnTypeWillChange]
     public function key()
     {
         return key($this->domCells);
     }
 
+    #[\ReturnTypeWillChange]
     public function next()
     {
         return next($this->domCells);
     }
+
+    #[\ReturnTypeWillChange]
     public function rewind()
     {
         return reset($this->domCells);
     }
+
     public function valid(): bool
     {
         return (bool)current($this->domCells);
diff --git a/tests/FastExcelTemplatorTest.php b/tests/FastExcelTemplatorTest.php
new file mode 100644
index 0000000..e757a25
--- /dev/null
+++ b/tests/FastExcelTemplatorTest.php
@@ -0,0 +1,89 @@
+<?php
+
+declare(strict_types=1);
+
+namespace avadim\FastExcelTemplator;
+
+use PHPUnit\Framework\TestCase;
+use avadim\FastExcelTemplator\Excel;
+
+final class FastExcelTemplatorTest extends TestCase
+{
+    const DEMO_DIR = __DIR__ . '/../demo/files/';
+
+    public function test01()
+    {
+        // =====================
+        $tpl = self::DEMO_DIR . 'demo1-tpl.xlsx';
+        $out = __DIR__ . '/demo1-out.xlsx';
+
+        $excel = Excel::template($tpl, $out);
+        $sheet = $excel->sheet();
+
+        $fillData = [
+            '{{COMPANY}}' => 'Comp Stock Shop',
+            '{{ADDRESS}}' => '123 ABC Street',
+            '{{CITY}}' => 'Peace City, TN',
+        ];
+        $replaceData = ['{{BULK_QTY}}' => 12, '{{DATE}}' => date('m/d/Y')];
+        $list = [
+            [
+                'number' => 'AA-8465-947563',
+                'description' => 'NEC Mate Type ML PC-MK29MLZD1FWG (Corei5-3470S/2GB/250GB/Multi/No OF/Win 11 Home)',
+                'price1' => 816,
+                'price2' => 683,
+            ],
+            [
+                'number' => 'QR-7956-048914',
+                'description' => 'Acer Aspire TC-1760-UA92 (Core i5-12400/12GB 3200MHz DDR4/512GB SSD/Win 11 Home)',
+                'price1' => 414,
+                'price2' => 339,
+            ],
+            [
+                'number' => 'BD-3966-285936',
+                'description' => 'Dell Optiplex 7050 SFF (Core i7-7700/32GB DDR4/1TB SSD/Win 10 Pro/Renewed)',
+                'price1' => 249,
+                'price2' => 198,
+            ],
+        ];
+
+        $sheet
+            ->fill($fillData)
+            ->replace($replaceData)
+        ;
+        $rowTemplate = $sheet->getRowTemplate(6);
+        $count = 0;
+        foreach ($list as $record) {
+            $rowData = [
+                // In the column A wil be written value from field 'number'
+                'A' => $record['number'],
+                // In the column B wil be written value from field 'description'
+                'B' => $record['description'],
+                // And so on...
+                'C' => $record['price1'],
+                'D' => $record['price2'],
+            ];
+            if ($count++ === 0) {
+                // First we replace the row 6 (this is template row)
+                $sheet->replaceRow(6, $rowTemplate, $rowData);
+            }
+            else {
+                // Then we add new rows after last touched
+                $sheet->insertRowAfterLast($rowTemplate, $rowData);
+            }
+        }
+        $excel->save();
+        $this->assertTrue(is_file($out));
+
+        $excelReader = \avadim\FastExcelReader\Excel::open($out);
+        $cells = $excelReader->readCells();
+
+        $this->assertEquals($fillData['{{COMPANY}}'], $cells['A1']);
+        $this->assertEquals('*Bulk pricing applies to quantities of 12 or more', $cells['D3']);
+        $this->assertEquals(249, $cells['C8']);
+
+        unlink($out);
+    }
+
+}
+
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
new file mode 100644
index 0000000..bf354f2
--- /dev/null
+++ b/tests/bootstrap.php
@@ -0,0 +1,11 @@
+<?php
+
+$vendorDir = __DIR__ . '/../../..';
+
+if (file_exists($file = $vendorDir . '/autoload.php')) {
+    require_once $file;
+} else if (file_exists($file = './vendor/autoload.php')) {
+    require_once $file;
+} else {
+    throw new \RuntimeException('Not found composer autoload');
+}
\ No newline at end of file