diff --git a/src/main/java/de/joethei/hs/java2/praktikum/praktikum2/CharCollection.java b/src/main/java/de/joethei/hs/java2/praktikum/praktikum2/CharCollection.java
index 753a973..481faaf 100644
--- a/src/main/java/de/joethei/hs/java2/praktikum/praktikum2/CharCollection.java
+++ b/src/main/java/de/joethei/hs/java2/praktikum/praktikum2/CharCollection.java
@@ -34,7 +34,7 @@ public class CharCollection {
     }
 
     public int different() {
-        Set<Character> set = (Set<Character>) this.list;
+        Set<Character> set = new HashSet<>(list);
         return set.size();
     }
 
diff --git a/src/test/java/de/joethei/hs/java2/tests/CharCollectionTest.java b/src/test/java/de/joethei/hs/java2/tests/CharCollectionTest.java
new file mode 100644
index 0000000..b76b11d
--- /dev/null
+++ b/src/test/java/de/joethei/hs/java2/tests/CharCollectionTest.java
@@ -0,0 +1,56 @@
+package de.joethei.hs.java2.tests;
+
+import de.joethei.hs.java2.praktikum.praktikum2.CharCollection;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class CharCollectionTest {
+
+    @Test
+    public void constructors() {
+        assertEquals(new CharCollection("Hallo"), new CharCollection('H', 'a', 'l', 'l', 'o'));
+    }
+
+    @Test
+    public void size() {
+        assertEquals(5, new CharCollection("Hallo").size());
+    }
+
+    @Test
+    public void count() {
+        assertEquals(2, new CharCollection("Hallo").count('l'));
+    }
+
+    @Test
+    public void different() {
+        assertEquals(4, new CharCollection("Hallo").different());
+    }
+
+    /*
+    @Test
+    public void top() {
+        assertEquals('l', new CharCollection("Hallo").top());
+    }
+
+    @Test
+    public void toStringTest() {
+        assertEquals("HalloWelt", new CharCollection("HalloWelt").toString());
+    }
+
+    @Test
+    public void moreThan() {
+        assertEquals(new CharCollection("ll"), new CharCollection("Hallo").moreThan(2));
+    }
+
+    @Test
+    public void except() {
+        assertEquals(new CharCollection("Hao"), new CharCollection("Hallo").except("l"));
+    }
+
+    @Test
+    public void isSubsect() {
+        assertTrue(new CharCollection("Hallo").isSubset("Hao"));
+    }
+    */
+ }
\ No newline at end of file