diff --git a/test/test_addition.c b/test/test_addition.c
index 51a9c46..3678b7f 100644
--- a/test/test_addition.c
+++ b/test/test_addition.c
@@ -4,7 +4,7 @@
 
 #include "addition.h"
 
-int* nullcarry = NULL;
+int carry[1];
 
 void setUp(void)
 {
@@ -19,7 +19,7 @@ void test_addition_full_adder_nullplusnullgleichnull(void)
     int result[1];
     int expected = 0;
 
-    full_adder(result, nullcarry, 0, 0, 0);
+    full_adder(result, carry, 0, 0, 0);
 
     TEST_ASSERT_EQUAL_INT(expected, result[0]);
 }
@@ -29,7 +29,7 @@ void test_addition_full_adder_nullplusnullgleichnullmituebertrag(void)
     int result[1];
     int expected = 1;
 
-    full_adder(result, nullcarry, 0, 0, 1);
+    full_adder(result, carry, 0, 0, 1);
 
     TEST_ASSERT_EQUAL_INT(expected, result[0]);
 }
@@ -39,11 +39,11 @@ void test_addition_full_adder_zahlpluszahlgleichsummeohneuebertrag(void)
     int result[5];
     int expected[5] = { 0, 1, 1, 1, 1};
 
-    full_adder((result+0), nullcarry, 1, 0, 1);
-    full_adder((result+1), nullcarry, 0, 1, 0);
-    full_adder((result+2), nullcarry, 1, 0, 0);
-    full_adder((result+3), nullcarry, 0, 0, 1);
-    full_adder((result+4), nullcarry, 1, 1, 1);
+    full_adder((result+0), carry, 1, 0, 1);
+    full_adder((result+1), carry, 0, 1, 0);
+    full_adder((result+2), carry, 1, 0, 0);
+    full_adder((result+3), carry, 0, 0, 1);
+    full_adder((result+4), carry, 1, 1, 1);
 
     TEST_ASSERT_EQUAL_INT(expected[0], result[0]);
     TEST_ASSERT_EQUAL_INT(expected[1], result[1]);