diff --git a/org.eclipse.scout.rt.platform.test/src/test/java/org/eclipse/scout/rt/platform/resource/MimeTypesTest.java b/org.eclipse.scout.rt.platform.test/src/test/java/org/eclipse/scout/rt/platform/resource/MimeTypesTest.java
index bed78e99675..2b7dcdabba5 100644
--- a/org.eclipse.scout.rt.platform.test/src/test/java/org/eclipse/scout/rt/platform/resource/MimeTypesTest.java
+++ b/org.eclipse.scout.rt.platform.test/src/test/java/org/eclipse/scout/rt/platform/resource/MimeTypesTest.java
@@ -18,8 +18,11 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.util.Collections;
+import java.util.List;
 import java.util.function.Consumer;
 
+import org.eclipse.scout.rt.platform.util.CollectionUtility;
 import org.eclipse.scout.rt.platform.util.HexUtility;
 import org.eclipse.scout.rt.platform.util.IOUtility;
 import org.eclipse.scout.rt.testing.platform.runner.PlatformTestRunner;
@@ -27,7 +30,7 @@
 import org.junit.runner.RunWith;
 
 /**
- * Test cases for {@link MimeTypes} and {@link IMimeMagic}.
+ * Test cases for {@link MimeType}, {@link MimeTypes} and {@link IMimeMagic}.
  */
 @RunWith(PlatformTestRunner.class)
 public class MimeTypesTest {
@@ -95,6 +98,34 @@ protected void runJpegTest(String content) {
     assertTrue(verifyMagic(binRes));
   }
 
+  @Test
+  public void testToFileExtensionsNullEmpty() {
+    assertTrue(MimeType.toFileExtensions(null).isEmpty());
+    assertTrue(MimeType.toFileExtensions(Collections.emptyList()).isEmpty());
+  }
+
+  @Test
+  public void testToFileExtensions() {
+    List<String> fileExtensions = MimeType.toFileExtensions(CollectionUtility.arrayList(MimeType.CSS, MimeType.BMP));
+    assertEquals(2, fileExtensions.size());
+    assertTrue(fileExtensions.contains(MimeType.CSS.getFileExtension()));
+    assertTrue(fileExtensions.contains(MimeType.BMP.getFileExtension()));
+  }
+
+  @Test
+  public void testToStringTypesNullEmpty() {
+    assertTrue(MimeType.toStringTypes(null).isEmpty());
+    assertTrue(MimeType.toStringTypes(Collections.emptyList()).isEmpty());
+  }
+
+  @Test
+  public void testToStringTypes() {
+    List<String> stringTypes = MimeType.toStringTypes(CollectionUtility.arrayList(MimeType.CSS, MimeType.BMP));
+    assertEquals(2, stringTypes.size());
+    assertTrue(stringTypes.contains(MimeType.CSS.getType()));
+    assertTrue(stringTypes.contains(MimeType.BMP.getType()));
+  }
+
   @Test
   public void testWave() {
     runWaveTest("5249 4646 2e2e 2e2e 5741 5645", true); // RIFF....WAVE