diff --git a/composer.json b/composer.json
index 61857e4..a41138a 100644
--- a/composer.json
+++ b/composer.json
@@ -23,6 +23,7 @@
     "d3/sensitive-message-formatter": "^1.0"
   },
   "require-dev": {
+    "phpunit/phpunit": "^10.5",
     "friendsofphp/php-cs-fixer": "^3.65",
     "phpstan/phpstan": "^2.0"
   },
@@ -37,6 +38,7 @@
     }
   },
   "scripts": {
+    "test": "./vendor/bin/phpunit",
     "check-style": "./vendor/bin/php-cs-fixer fix --verbose --dry-run",
     "fix-style": "./vendor/bin/php-cs-fixer fix --verbose",
     "check-code": "./vendor/bin/phpstan analyse -c phpstan.neon --no-progress --ansi"
diff --git a/phpunit.xml b/phpunit.xml
new file mode 100644
index 0000000..4de3656
--- /dev/null
+++ b/phpunit.xml
@@ -0,0 +1,20 @@
+<?xml version="1.0"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         bootstrap="vendor/autoload.php"
+         convertErrorsToExceptions="true"
+         convertNoticesToExceptions="true"
+         convertWarningsToExceptions="true"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd">
+    <coverage>
+        <include>
+            <directory suffix=".php">src</directory>
+        </include>
+        <report>
+            <clover outputFile="build/logs/clover.xml"/>
+        </report>
+    </coverage>
+    <testsuite name="GuzzleFactory">
+        <directory>./tests</directory>
+    </testsuite>
+    <logging/>
+</phpunit>
diff --git a/tests/ApiTestCase.php b/tests/ApiTestCase.php
new file mode 100644
index 0000000..6da590f
--- /dev/null
+++ b/tests/ApiTestCase.php
@@ -0,0 +1,75 @@
+<?php
+
+/**
+ * Copyright (c) D3 Data Development (Inh. Thomas Dartsch)
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ *
+ * https://www.d3data.de
+ *
+ * @copyright (C) D3 Data Development (Inh. Thomas Dartsch)
+ * @author    D3 Data Development - Daniel Seifert <info@shopmodule.com>
+ * @link      https://www.oxidmodule.com
+ */
+
+declare(strict_types=1);
+
+namespace D3\OxidGuzzleFactory\tests;
+
+use PHPUnit\Framework\TestCase;
+use ReflectionClass;
+use ReflectionException;
+
+abstract class ApiTestCase extends TestCase
+{
+    /**
+     * Calls a private or protected object method.
+     *
+     * @param object $object
+     * @param string $methodName
+     * @param array $arguments
+     *
+     * @return mixed
+     * @throws ReflectionException
+     */
+    public function callMethod(object $object, string $methodName, array $arguments = []): mixed
+    {
+        $class = new ReflectionClass($object);
+        $method = $class->getMethod($methodName);
+        $method->setAccessible(true);
+        return $method->invokeArgs($object, $arguments);
+    }
+
+    /**
+     * Sets a private or protected property in defined class instance
+     *
+     * @param object $object
+     * @param string $valueName
+     * @param $value
+     * @throws ReflectionException
+     */
+    public function setValue(object $object, string $valueName, $value): void
+    {
+        $reflection = new ReflectionClass($object);
+        $property = $reflection->getProperty($valueName);
+        $property->setAccessible(true);
+        $property->setValue($object, $value);
+    }
+
+    /**
+     * get a private or protected property from defined class instance
+     *
+     * @param object $object
+     * @param string $valueName
+     * @return mixed
+     * @throws ReflectionException
+     */
+    public function getValue(object $object, string $valueName): mixed
+    {
+        $reflection = new ReflectionClass($object);
+        $property = $reflection->getProperty($valueName);
+        $property->setAccessible(true);
+        return $property->getValue($object);
+    }
+}
diff --git a/tests/GuzzleFactoryTest.php b/tests/GuzzleFactoryTest.php
new file mode 100644
index 0000000..e467e3b
--- /dev/null
+++ b/tests/GuzzleFactoryTest.php
@@ -0,0 +1,35 @@
+<?php
+
+/**
+ * Copyright (c) D3 Data Development (Inh. Thomas Dartsch)
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ *
+ * https://www.d3data.de
+ *
+ * @copyright (C) D3 Data Development (Inh. Thomas Dartsch)
+ * @author    D3 Data Development - Daniel Seifert <info@shopmodule.com>
+ * @link      https://www.oxidmodule.com
+ */
+
+declare(strict_types=1);
+
+namespace D3\OxidGuzzleFactory\tests;
+
+use D3\OxidGuzzleFactory\GuzzleFactory;
+
+class GuzzleFactoryTest extends ApiTestCase
+{
+    /**
+     * @test
+     * @return void
+     * @covers \D3\OxidGuzzleFactory\GuzzleFactory::create
+     */
+    public function testCreate(): void
+    {
+        $instance = GuzzleFactory::create();
+
+        $this->assertInstanceOf(GuzzleFactory::class, $instance);
+    }
+}
\ No newline at end of file
diff --git a/tests/README.md b/tests/README.md
new file mode 100644
index 0000000..675801b
--- /dev/null
+++ b/tests/README.md
@@ -0,0 +1,11 @@
+# Installation
+
+```
+composer create-project -s dev --prefer-source [--repository '{"type": "vcs", "url": "repository url"}'] d3/guzzle-factory .
+```
+
+# Run tests
+
+```
+./vendor/bin/phpunit [--no-coverage] [--coverage-html=cov]
+```