diff -r db8299984bfe -r 6a842bd49fea tests/test_hash_map.c
--- a/tests/test_hash_map.c	Mon Dec 22 15:47:59 2025 +0100
+++ b/tests/test_hash_map.c	Mon Dec 22 16:12:20 2025 +0100
@@ -1611,7 +1611,8 @@
         CX_TEST_ASSERT(keyiter.index == map->collection.size);
         // verify that all keys are mapped to values in reference map
         for (size_t i = 0 ; i < map->collection.size ; i++) {
-            cxmutstr ksz = cx_strdup(cx_strn(keys[i].data, keys[i].len));
+            // need to create a zero-terminated string from the key
+            cxmutstr ksz = cx_strdup(cx_hash_key_as_string(&keys[i]));
             CX_TEST_ASSERT(test_map_reference_get(ksz.ptr) != NULL);
             cx_strfree(&ksz);
         }
@@ -1652,7 +1653,7 @@
         struct test_map_kv *pairs = calloc(map->collection.size, sizeof(struct test_map_kv));
         cx_foreach(CxMapEntry*, entry, pairiter) {
             const CxHashKey *key = entry->key;
-            pairs[pairiter.index].key = cx_strdup(cx_strn(key->data, key->len)).ptr;
+            pairs[pairiter.index].key = cx_strdup(cx_hash_key_as_string(key)).ptr;
             pairs[pairiter.index].value = entry->value;
         }
         CX_TEST_ASSERT(pairiter.index == map->collection.size);