diff --git a/tests/unit/test_composites.c b/tests/unit/test_composites.c
index a7f54d186..c135d5fb7 100644
--- a/tests/unit/test_composites.c
+++ b/tests/unit/test_composites.c
@@ -43,7 +43,7 @@
  */
 
 #define NC 4
-#define NT 11
+#define NT 12
 
 // fixed label array
 static elabel_t label[NT];
@@ -59,6 +59,7 @@ static eterm_t g = 7;
 static eterm_t h = 8;
 static eterm_t i = 9;
 static eterm_t j = 10;
+static eterm_t k = 11;
 
 
 #define NCMP 50
@@ -88,6 +89,8 @@ static void init_labels(void) {
   label[h] = pos_label(3);
   label[i] = pos_label(3);
   label[j] = pos_label(3);
+
+  label[k] = pos_label(4);
 };
 
 /*
diff --git a/tests/unit/test_concrete_values3.c b/tests/unit/test_concrete_values3.c
index 57d112136..62d499f2c 100644
--- a/tests/unit/test_concrete_values3.c
+++ b/tests/unit/test_concrete_values3.c
@@ -226,7 +226,7 @@ static void init_buffer1(void) {
   for (i=0; i<BUFFER_SIZE; i++) {
     buffer1[i] = val[j];
     j ++;
-    if (j > NVALS) j = 0;
+    if (j >= NVALS) j = 0;
   }
 }