adapted bintreeTest to nex nextTreeData Function

bintreeTests.c

@@ -115,7 +115,7 @@ void test_nextTreeDataReturnsNextDataCorrectly(void)
     // check if nextTreeData returns Data correctly
     TEST_ASSERT_NOT_NULL(entry);
 
-    TEST_ASSERT_EQUAL(score7, *(int *)nextTreeData(NULL));
+    TEST_ASSERT_EQUAL(score7, *(int *)entry);
     TEST_ASSERT_EQUAL(score3, *(int *)nextTreeData(NULL));
     TEST_ASSERT_EQUAL(score6, *(int *)nextTreeData(NULL));
     TEST_ASSERT_EQUAL(score1, *(int *)nextTreeData(NULL));