diff --git a/tests/Models/NullCollectionTest.php b/tests/Models/NullCollectionTest.php
index 9fe93dd..703fcd6 100755
--- a/tests/Models/NullCollectionTest.php
+++ b/tests/Models/NullCollectionTest.php
@@ -23,7 +23,7 @@ final class NullCollectionTest extends \PHPUnit\Framework\TestCase
 {
     /**
      * @covers Modules\Media\Models\NullCollection
-     * @group framework
+     * @group module
      */
     public function testNull() : void
     {
@@ -32,11 +32,21 @@ final class NullCollectionTest extends \PHPUnit\Framework\TestCase
 
     /**
      * @covers Modules\Media\Models\NullCollection
-     * @group framework
+     * @group module
      */
     public function testId() : void
     {
         $null = new NullCollection(2);
         self::assertEquals(2, $null->id);
     }
+
+    /**
+     * @covers Modules\Media\Models\NullCollection
+     * @group module
+     */
+    public function testJsonSerialize() : void
+    {
+        $null = new NullCollection(2);
+        self::assertEquals(['id' => 2], $null);
+    }
 }
diff --git a/tests/Models/NullMediaContentTest.php b/tests/Models/NullMediaContentTest.php
index 9dad8c5..e1103ea 100644
--- a/tests/Models/NullMediaContentTest.php
+++ b/tests/Models/NullMediaContentTest.php
@@ -23,7 +23,7 @@ final class NullMediaContentTest extends \PHPUnit\Framework\TestCase
 {
     /**
      * @covers Modules\Media\Models\NullMediaContent
-     * @group framework
+     * @group module
      */
     public function testNull() : void
     {
@@ -32,7 +32,7 @@ final class NullMediaContentTest extends \PHPUnit\Framework\TestCase
 
     /**
      * @covers Modules\Media\Models\NullMediaContent
-     * @group framework
+     * @group module
      */
     public function testId() : void
     {
@@ -42,7 +42,7 @@ final class NullMediaContentTest extends \PHPUnit\Framework\TestCase
 
     /**
      * @covers Modules\Media\Models\NullMediaContent
-     * @group framework
+     * @group module
      */
     public function testJsonSerialize() : void
     {
diff --git a/tests/Models/NullMediaTest.php b/tests/Models/NullMediaTest.php
index e7a54da..9ef8cd1 100755
--- a/tests/Models/NullMediaTest.php
+++ b/tests/Models/NullMediaTest.php
@@ -23,7 +23,7 @@ final class NullMediaTest extends \PHPUnit\Framework\TestCase
 {
     /**
      * @covers Modules\Media\Models\NullMedia
-     * @group framework
+     * @group module
      */
     public function testNull() : void
     {
@@ -32,11 +32,21 @@ final class NullMediaTest extends \PHPUnit\Framework\TestCase
 
     /**
      * @covers Modules\Media\Models\NullMedia
-     * @group framework
+     * @group module
      */
     public function testId() : void
     {
         $null = new NullMedia(2);
         self::assertEquals(2, $null->id);
     }
+
+    /**
+     * @covers Modules\Media\Models\NullMedia
+     * @group module
+     */
+    public function testJsonSerialize() : void
+    {
+        $null = new NullMedia(2);
+        self::assertEquals(['id' => 2], $null);
+    }
 }
diff --git a/tests/Models/NullMediaTypeTest.php b/tests/Models/NullMediaTypeTest.php
index eb0089b..fa8d631 100755
--- a/tests/Models/NullMediaTypeTest.php
+++ b/tests/Models/NullMediaTypeTest.php
@@ -23,7 +23,7 @@ final class NullMediaTypeTest extends \PHPUnit\Framework\TestCase
 {
     /**
      * @covers Modules\Media\Models\NullMediaType
-     * @group framework
+     * @group module
      */
     public function testNull() : void
     {
@@ -32,11 +32,21 @@ final class NullMediaTypeTest extends \PHPUnit\Framework\TestCase
 
     /**
      * @covers Modules\Media\Models\NullMediaType
-     * @group framework
+     * @group module
      */
     public function testId() : void
     {
         $null = new NullMediaType(2);
         self::assertEquals(2, $null->id);
     }
+
+    /**
+     * @covers Modules\Media\Models\NullMediaType
+     * @group module
+     */
+    public function testJsonSerialize() : void
+    {
+        $null = new NullMediaType(2);
+        self::assertEquals(['id' => 2], $null);
+    }
 }
diff --git a/tests/Models/NullReferenceTest.php b/tests/Models/NullReferenceTest.php
index 1ea9ef3..232f7cc 100644
--- a/tests/Models/NullReferenceTest.php
+++ b/tests/Models/NullReferenceTest.php
@@ -23,7 +23,7 @@ final class NullReferenceTest extends \PHPUnit\Framework\TestCase
 {
     /**
      * @covers Modules\Media\Models\NullReference
-     * @group framework
+     * @group module
      */
     public function testNull() : void
     {
@@ -32,7 +32,7 @@ final class NullReferenceTest extends \PHPUnit\Framework\TestCase
 
     /**
      * @covers Modules\Media\Models\NullReference
-     * @group framework
+     * @group module
      */
     public function testId() : void
     {
@@ -42,7 +42,7 @@ final class NullReferenceTest extends \PHPUnit\Framework\TestCase
 
     /**
      * @covers Modules\Media\Models\NullReference
-     * @group framework
+     * @group module
      */
     public function testJsonSerialize() : void
     {