diff --git a/qtism/data/AssessmentItem.php b/qtism/data/AssessmentItem.php
index 67fd9ef15..aec4ed8ff 100644
--- a/qtism/data/AssessmentItem.php
+++ b/qtism/data/AssessmentItem.php
@@ -222,7 +222,7 @@ public function __construct($identifier, $title, $timeDependent, $lang = '')
      */
     public function setIdentifier($identifier)
     {
-        if (Format::isIdentifier($identifier, false)) {
+        if (Format::isNormalizedString($identifier)) {
             $this->identifier = $identifier;
             $this->notify();
         } else {
diff --git a/test/qtismtest/data/AssessmentItemTest.php b/test/qtismtest/data/AssessmentItemTest.php
new file mode 100644
index 000000000..f3509fd94
--- /dev/null
+++ b/test/qtismtest/data/AssessmentItemTest.php
@@ -0,0 +1,136 @@
+<?php
+
+/**
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; under version 2
+ * of the License (non-upgradable).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Copyright (c) 2024 (original work) Open Assessment Technologies SA;
+ */
+
+declare(strict_types=1);
+
+namespace qtismtest\data;
+
+use InvalidArgumentException;
+use PHPUnit\Framework\TestCase;
+use qtism\data\AssessmentItem;
+use qtism\data\content\ItemBody;
+use qtism\data\content\ModalFeedbackCollection;
+use qtism\data\content\StylesheetCollection;
+use qtism\data\processing\ResponseProcessing;
+use qtism\data\QtiComponentCollection;
+use qtism\data\state\OutcomeDeclarationCollection;
+use qtism\data\state\ResponseDeclarationCollection;
+use qtism\data\state\TemplateDeclarationCollection;
+
+class AssessmentItemTest extends TestCase
+{
+    /**
+     * @var AssessmentItem
+     */
+    private $subject;
+    public function setUp(): void
+    {
+        $this->subject = new AssessmentItem(
+            '123456789 asbcdżć',
+            'title string',
+            true,
+            'pinglish'
+        );
+    }
+
+    public function testAssessmentItemCreation(): void
+    {
+        $this->assertEquals('123456789 asbcdżć', $this->subject->getIdentifier());
+        $this->assertEquals('title string', $this->subject->getTitle());
+        $this->assertTrue($this->subject->isTimeDependent());
+        $this->assertInstanceOf(ResponseDeclarationCollection::class, $this->subject->getResponseDeclarations());
+        $this->assertInstanceOf(OutcomeDeclarationCollection::class, $this->subject->getOutcomeDeclarations());
+        $this->assertInstanceOf(TemplateDeclarationCollection::class, $this->subject->getTemplateDeclarations());
+        $this->assertInstanceOf(StylesheetCollection::class, $this->subject->getStylesheets());
+        $this->assertInstanceOf(ModalFeedbackCollection::class, $this->subject->getModalFeedbacks());
+        $this->assertEquals('assessmentItem', $this->subject->getQtiClassName());
+        $this->assertInstanceOf(QtiComponentCollection::class, $this->subject->getComponents());
+    }
+
+    public function testAssessmentItemSetters(): void
+    {
+        $this->subject->setResponseProcessing(new ResponseProcessing());
+        $this->subject->setToolName('toolName shorter 256 characters');
+        $this->subject->setToolVersion('Tool version string shorter than 256 characters');
+
+        $this->subject->setItemBody(
+            new ItemBody('idString', 'classString', 'langString', 'labelString')
+        );
+
+        $this->assertInstanceOf(StylesheetCollection::class, $this->subject->getStylesheets());
+        $this->assertInstanceOf(ItemBody::class, $this->subject->getItemBody());
+        $this->assertInstanceOf(ResponseProcessing::class, $this->subject->getResponseProcessing());
+        $this->assertInstanceOf(ModalFeedbackCollection::class, $this->subject->getModalFeedbacks());
+        $this->assertEquals('assessmentItem', $this->subject->getQtiClassName());
+        $this->assertInstanceOf(QtiComponentCollection::class, $this->subject->getComponents());
+        $this->assertEquals('toolName shorter 256 characters', $this->subject->getToolName());
+        $this->assertTrue($this->subject->hasToolName());
+        $this->assertEquals('Tool version string shorter than 256 characters', $this->subject->getToolVersion());
+        $this->assertTrue($this->subject->hasToolVersion());
+        $this->assertInstanceOf(ItemBody::class, $this->subject->getItemBody());
+        $this->assertTrue($this->subject->hasItemBody());
+    }
+
+    /**
+     * @dataProvider getInvalidAssessmentItemData
+     */
+    public function testAssessmentItemValidation($identifier, $title, $timeDependent, $lang)
+    {
+        $this->expectException(InvalidArgumentException::class);
+        new AssessmentItem($identifier, $title, $timeDependent, $lang);
+    }
+
+    public function setToolNameTest()
+    {
+        $this->expectException(InvalidArgumentException::class);
+        $this->subject->setToolName(str_repeat('a', 257));
+    }
+
+    public function setToolVersionTest()
+    {
+        $this->expectException(InvalidArgumentException::class);
+        $this->subject->setToolVersion(str_repeat('a', 257));
+    }
+
+    public function getInvalidAssessmentItemData()
+    {
+        return [
+            'Wrong identifier' => ["string \t with tab", 'title string', true ,'pinglish'],
+            'Wrong title' => [
+                '123456789 asbcdżć',
+                1234,
+                true,
+                'pinglish'
+            ],
+            'Wrong isTimeDependent' => [
+                '123456789 asbcdżć',
+                'title string',
+                'true',
+                'pinglish'
+            ],
+            'Wrong lang' => [
+                '123456789 asbcdżć',
+                'title string',
+                'true',
+                true
+            ],
+        ];
+    }
+}