diff --git a/Tests/ApiTestCase.php b/Tests/ApiTestCase.php
new file mode 100644
index 0000000..2657f16
--- /dev/null
+++ b/Tests/ApiTestCase.php
@@ -0,0 +1,60 @@
+<?php
+
+namespace D3\LinkmobilityClient\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 = array()): 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)
+    {
+        $reflection = new ReflectionClass($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/ClientTest.php b/Tests/ClientTest.php
new file mode 100644
index 0000000..c92ceda
--- /dev/null
+++ b/Tests/ClientTest.php
@@ -0,0 +1,28 @@
+<?php
+
+namespace D3\LinkmobilityClient\Tests;
+
+use D3\LinkmobilityClient\Client;
+
+class ApiClientTest extends ApiTestCase
+{
+    public string $fixtureApiKey = 'fixtureApiKey';
+    /** @var ApiClient */
+    public Client $api;
+    public string $jsonFixture = 'json_content';
+
+    public function setUp():void
+    {
+        parent::setUp();
+
+        $this->api = new Client($this->fixtureApiKey);
+    }
+    
+    /**
+     * @test
+     */
+    public function testRun()
+    {
+        $this->assertTrue(true);
+    }
+}
diff --git a/Tests/README.md b/Tests/README.md
new file mode 100644
index 0000000..656b7db
--- /dev/null
+++ b/Tests/README.md
@@ -0,0 +1,11 @@
+# Installation
+
+```
+composer create-project -s dev --prefer-source --repository="{\"url\": \"gitfhfac@git.d3data.de:D3Private/linkmobility-php-client.git\", \"type\": \"vcs\"}" d3/linkmobility-php-client .
+```
+
+# Run tests
+
+```
+./vendor/bin/phpunit [--no-coverage]
+```
diff --git a/composer.json b/composer.json
index e23b90a..9131273 100644
--- a/composer.json
+++ b/composer.json
@@ -28,12 +28,14 @@
         "ext-json": "*"
     },
     "require-dev": {
-        "phpunit/phpunit" : "~5.7||~6.0",
+    	"php": "^7.2",
+        "phpunit/phpunit" : "^8.0",
         "friendsofphp/php-cs-fixer": "^2.0"
     },
     "autoload": {
         "psr-4": {
-            "D3\\LinkmobilityClient\\": "src"
+            "D3\\LinkmobilityClient\\": "src",
+            "D3\\LinkmobilityClient\\Tests\\": "Tests"
         }
     },
     "scripts": {
diff --git a/phpunit.xml b/phpunit.xml
new file mode 100644
index 0000000..14a145c
--- /dev/null
+++ b/phpunit.xml
@@ -0,0 +1,22 @@
+
+<phpunit
+    bootstrap="vendor/autoload.php"
+    convertErrorsToExceptions="true"
+    convertNoticesToExceptions="true"
+    convertWarningsToExceptions="true">
+
+    <testsuite name="tankerkoenig">
+        <directory>./Tests</directory>
+    </testsuite>
+
+    <filter>
+        <whitelist>
+            <directory suffix=".php">src</directory>
+        </whitelist>
+    </filter>
+
+    <logging>
+        <log type="coverage-clover" target="build/logs/clover.xml"/>
+    </logging>
+
+</phpunit>