diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5063eb9..df71e4a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -70,3 +70,49 @@ jobs:
         run: "composer update --no-progress"
       - name: "Run the tests"
         run: "composer ci:tests:unit"
+
+  functional-tests:
+    name: Functional Tests
+    runs-on: ubuntu-22.04
+    needs: [ code-quality ]
+    strategy:
+      matrix:
+        php-version:
+          - '8.2'
+          - '8.3'
+    env:
+      DB_DATABASE: typo3
+      DB_USER: root
+      DB_PASSWORD: root
+      DB_HOST: 127.0.0.1
+
+    steps:
+      - name: "Checkout"
+        uses: actions/checkout@v4
+      - name: "Install PHP"
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: "${{ matrix.php-version }}"
+          coverage: none
+          tools: composer:v2.6
+      - name: "Show Composer version"
+        run: composer --version
+      - name: "Show the Composer configuration"
+        run: composer config --global --list
+      - name: "Cache dependencies installed with composer"
+        uses: actions/cache@v4
+        with:
+          key: "php${{ matrix.php-version }}-composer-${{ hashFiles('**/composer.json') }}"
+          path: ~/.cache/composer
+          restore-keys: "php${{ matrix.php-version }}-composer-\n"
+      - name: "Install Composer dependencies"
+        run: "composer update --no-progress"
+      - name: "Start MySQL"
+        run: "sudo /etc/init.d/mysql start"
+      - name: "Run the tests"
+        run: |
+          export typo3DatabaseName="$DB_DATABASE";
+          export typo3DatabaseHost="$DB_HOST";
+          export typo3DatabaseUsername="$DB_USER";
+          export typo3DatabasePassword="$DB_PASSWORD";
+          composer ci:tests:functional
diff --git a/Classes/Domain/Model/PublishedItem.php b/Classes/Domain/Model/PublishedItem.php
index df77fb3..0967e12 100755
--- a/Classes/Domain/Model/PublishedItem.php
+++ b/Classes/Domain/Model/PublishedItem.php
@@ -968,7 +968,7 @@ public function getComposers(): string
         return Collection::wrap($this->containedWorks->toArray())->
             map( function($work) { return self::getWorkComposerName($work); } )->
             unique()->
-            join(';');
+            join('; ');
     }
 
     protected static function getComposerName(GndPerson $composer): string
diff --git a/Tests/Functional/Domain/Model/PublishedItemTest.php b/Tests/Functional/Domain/Model/PublishedItemTest.php
new file mode 100644
index 0000000..d2cc768
--- /dev/null
+++ b/Tests/Functional/Domain/Model/PublishedItemTest.php
@@ -0,0 +1,141 @@
+<?php
+namespace Slub\MpdbCore\Tests\Unit\Domain\Model;
+
+use Slub\DmNorm\Domain\Model\GndPerson;
+use Slub\DmNorm\Domain\Model\GndWork;
+use Slub\MpdbCore\Domain\Model\PublishedItem;
+use Slub\MpdbCore\Domain\Model\PublishedSubitem;
+use TYPO3\CMS\Extbase\Persistence\ObjectStorage;
+use TYPO3\TestingFramework\Core\Functional\FunctionalTestCase;
+
+/**
+ * Test case.
+ *
+ * @author Matthias Richter <matthias.richter@slub-dresden.de>
+ */
+class PublishedItemTest extends FunctionalTestCase
+{
+    /**
+     * @var \Slub\PublisherDb\Domain\Model\PublishedItem
+     */
+    protected ?PublishedItem $subject = null;
+
+    /**
+     * @var \Slub\DmNorm\Domain\Model\GndPerson
+     */
+    protected ?GndPerson $composer1 = null;
+
+    /**
+     * @var \Slub\DmNorm\Domain\Model\GndPerson
+     */
+    protected ?GndPerson $composer2 = null;
+
+    /**
+     * @var \Slub\DmNorm\Domain\Model\GndWork
+     */
+    protected ?GndWork $work1 = null;
+
+    /**
+     * @var \Slub\DmNorm\Domain\Model\GndWork
+     */
+    protected ?GndWork $work2 = null;
+
+    /**
+     * @var string
+     */
+    protected string $nameComposer1 = 'Composer 1';
+
+    /**
+     * @var string
+     */
+    protected string $nameComposer2 = 'Composer 2';
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->subject = new PublishedItem();
+
+        $this->composer1 = new GndPerson();
+        $this->composer2 = new GndPerson();
+        $this->composer1->setName($this->nameComposer1);
+        $this->composer2->setName($this->nameComposer2);
+
+        $this->work1 = new GndWork();
+        $this->work2 = new GndWork();
+        $this->work1->setFirstComposer($this->composer1);
+        $this->work2->setFirstComposer($this->composer2);
+    }
+
+    protected function tearDown(): void
+    {
+        parent::tearDown();
+    }
+
+    /**
+     * @test
+     */
+    public function publishedItemWithOneComposerReturnsComposer()
+    {
+        $this->subject->addFirstComposer($this->composer1);
+
+        self::assertSame(
+            $this->nameComposer1,
+            $this->subject->getComposers()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function publishedItemWithManyComposersReturnsComposers()
+    {
+        $this->subject->addFirstComposer($this->composer1);
+        $this->subject->addFirstComposer($this->composer2);
+        $namesString = implode('; ', [$this->nameComposer1, $this->nameComposer2]);
+
+        self::assertSame(
+            $namesString,
+            $this->subject->getComposers()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function publishedItemWithoutComposersReturnsOneWorkComposer()
+    {
+        $this->subject->addContainedWork($this->work1);
+
+        self::assertSame(
+            $this->nameComposer1,
+            $this->subject->getComposers()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function publishedItemWithoutComposerReturnsManyWorkComposers()
+    {
+        $this->subject->addContainedWork($this->work1);
+        $this->subject->addContainedWork($this->work2);
+        $namesString = implode('; ', [$this->nameComposer1, $this->nameComposer2]);
+
+        self::assertSame(
+            $namesString,
+            $this->subject->getComposers()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function publishedItemWithoutComposerWithoutWorkcomposersReturnsString()
+    {
+        self::assertSame(
+            '',
+            $this->subject->getComposers()
+        );
+    }
+
+}
diff --git a/composer.json b/composer.json
index 73a53db..107dd39 100755
--- a/composer.json
+++ b/composer.json
@@ -47,8 +47,9 @@
         "ci": [ "@ci:php", "@ci:tests" ],
         "ci:php": [ "@ci:php:stan" ],
         "ci:php:stan": [ "phpstan analyse Classes" ],
-        "ci:tests": [ "@ci:tests:unit" ],
-        "ci:tests:unit": [ "phpunit -c config/UnitTests.xml" ]
+        "ci:tests": [ "@ci:tests:unit", "@ci:tests:functional" ],
+        "ci:tests:unit": [ "phpunit -c config/UnitTests.xml" ],
+        "ci:tests:functional": [ "phpunit -c config/FunctionalTests.xml" ]
     },
     "extra": {
         "typo3/cms": {
diff --git a/config/FunctionalTests.xml b/config/FunctionalTests.xml
new file mode 100644
index 0000000..8fbde7e
--- /dev/null
+++ b/config/FunctionalTests.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.4/phpunit.xsd"
+         backupGlobals="true"
+         beStrictAboutTestsThatDoNotTestAnything="false"
+         bootstrap="../.Build/vendor/typo3/testing-framework/Resources/Core/Build/UnitTestsBootstrap.php"
+         cacheResult="false"
+         colors="true"
+         failOnRisky="true"
+         failOnWarning="true"
+>
+    <testsuites>
+        <testsuite name="MpdbCore">
+            <directory>../Tests/Functional</directory>
+        </testsuite>
+    </testsuites>
+
+    <php>
+        <!--
+            @deprecated: Set this to not suppress warnings, notices and deprecations in functional tests
+                         with TYPO3 core v11 and up.
+                         Will always be done with next major version.
+                         To still suppress warnings, notices and deprecations, do NOT define the constant at all.
+         -->
+        <const name="TYPO3_TESTING_FUNCTIONAL_REMOVE_ERROR_HANDLER" value="true"/>
+        <ini name="display_errors" value="1"/>
+        <env name="TYPO3_CONTEXT" value="Testing"/>
+    </php>
+</phpunit>
diff --git a/config/UnitTests.xml b/config/UnitTests.xml
index a644f4f..81d74fd 100644
--- a/config/UnitTests.xml
+++ b/config/UnitTests.xml
@@ -8,7 +8,6 @@
          colors="true"
          failOnRisky="true"
          failOnWarning="true"
-         requireCoverageMetadata="true"
 >
     <testsuites>
         <testsuite name="MpdbCore">
@@ -16,12 +15,6 @@
         </testsuite>
     </testsuites>
 
-    <source>
-        <include>
-            <directory>../Classes</directory>
-        </include>
-    </source>
-
     <php>
         <ini name="display_errors" value="1"/>
         <env name="TYPO3_CONTEXT" value="Testing"/>