diff --git a/src/main/c/Tim/SchereSteinPapier.c b/src/main/c/Tim/SchereSteinPapier.c
index 3b71014..12b9735 100644
--- a/src/main/c/Tim/SchereSteinPapier.c
+++ b/src/main/c/Tim/SchereSteinPapier.c
@@ -43,7 +43,9 @@ void schereSteinPapier()
     }
 }
 
-
+//Berechnung,welche Auswahl gewinnt.
+//@return: 0 = unentschieden; 1 = gewonnen; -1 = verloren; 3 = Fehler bei der Wertübergabe
+//@param x = UserChoice; y = COMChoice
 int calculateWinner(int x, int y)
 {
     switch (x)
@@ -78,5 +80,7 @@ int calculateWinner(int x, int y)
 
                 default: return 3;
             }
+        default: return 3;
     }
+
 }
\ No newline at end of file
diff --git a/src/test/c/Tim/test_SchereSteinPapier.c b/src/test/c/Tim/test_SchereSteinPapier.c
index bbe81fe..2b1d348 100644
--- a/src/test/c/Tim/test_SchereSteinPapier.c
+++ b/src/test/c/Tim/test_SchereSteinPapier.c
@@ -1,5 +1,6 @@
 #include "SchereSteinPapier.h"
 #include "unity.h"
+#include <stdlib.h>
 
 void setUp(void)
 {
@@ -88,5 +89,42 @@ void test_Win_USER_Paper_COM_Rock()
 
     int actualResult = calculateWinner(3,2);
 
+    TEST_ASSERT_EQUAL_INT(expectedResult, actualResult);
+}
+
+
+void test_USER_unknownParameter_Rock_randomChoice()
+{
+    int expectedResult = 3;
+
+    int actualResult = calculateWinner(5,rand() % 3 + 1);
+
+    TEST_ASSERT_EQUAL_INT(expectedResult, actualResult);
+}
+
+void test_USER_randomChoice_Rock_unknownParameter()
+{
+    int expectedResult = 3;
+
+    int actualResult = calculateWinner(rand() % 3 + 1, 5);
+
+    TEST_ASSERT_EQUAL_INT(expectedResult, actualResult);
+}
+
+void test_USER_randomChoice_Rock_zero()
+{
+    int expectedResult = 3;
+
+    int actualResult = calculateWinner(rand() % 3 + 1, 0);
+
+    TEST_ASSERT_EQUAL_INT(expectedResult, actualResult);
+}
+
+void test_USER_zero_Rock_randomChoice()
+{
+    int expectedResult = 3;
+
+    int actualResult = calculateWinner(0, rand() % 3 + 1);
+
     TEST_ASSERT_EQUAL_INT(expectedResult, actualResult);
 }
\ No newline at end of file