diff -r 244fb8bc3584 -r 6986e9ed70f3 tests/test_hash_map.c
--- a/tests/test_hash_map.c	Fri Oct 24 20:52:10 2025 +0200
+++ b/tests/test_hash_map.c	Fri Oct 24 21:15:14 2025 +0200
@@ -513,8 +513,11 @@
     cx_testing_allocator_destroy(&talloc);
 }
 
+static unsigned test_hash_map_clone_func_max_clones;
 static void *test_hash_map_clone_func(void *dst, const void *src,
         const CxAllocator *al, void *data) {
+    if (test_hash_map_clone_func_max_clones == 0) return NULL;
+    test_hash_map_clone_func_max_clones--;
     if (dst == NULL) {
         dst = cxMalloc(al, sizeof(int));
     }
@@ -535,6 +538,7 @@
     }
     CX_TEST_DO {
         int c = 4;
+        test_hash_map_clone_func_max_clones = 100; // no limit
         size_t cloned = cxMapClone(dst, src, test_hash_map_clone_func, NULL, &c);
         CX_TEST_ASSERT(cloned == 3);
         CX_TEST_ASSERT(cxMapSize(dst) == 5);
@@ -552,6 +556,38 @@
     cxMapFree(src);
 }
 
+CX_TEST(test_hash_map_clone_alloc_fail) {
+    CxMap *dst = cxHashMapCreateSimple(sizeof(int));
+    CxMap *src = cxHashMapCreateSimple(sizeof(int));
+    const char *exist_keys[] = {"k1", "k2", "k3"};
+    int exists[] = {1, 3, 4};
+    const char *source_keys[] = {"k4", "k2", "k5"};
+    int source[] = {7, 9, 15};
+    for (unsigned int i = 0 ; i < 3 ; i++) {
+        cxMapPut(dst, exist_keys[i], &exists[i]);
+        cxMapPut(src, source_keys[i], &source[i]);
+    }
+    CX_TEST_DO {
+        int c = 4;
+        test_hash_map_clone_func_max_clones = 2;
+        size_t cloned = cxMapClone(dst, src, test_hash_map_clone_func, NULL, &c);
+        CX_TEST_ASSERT(cloned == 2);
+        CX_TEST_ASSERT(cxMapSize(dst) == 4);
+        CX_TEST_ASSERT(*((int*)cxMapGet(dst, "k1")) == 1);
+        CX_TEST_ASSERT(*((int*)cxMapGet(dst, "k2")) == 13);
+        CX_TEST_ASSERT(*((int*)cxMapGet(dst, "k3")) == 4);
+        // the concrete element which is affected might change when the hash function changes
+        CX_TEST_ASSERT(cxMapGet(dst, "k4") == NULL);
+        CX_TEST_ASSERT(*((int*)cxMapGet(dst, "k5")) == 19);
+        CX_TEST_ASSERT(cxMapSize(src) == 3);
+        CX_TEST_ASSERT(*((int*)cxMapGet(src, "k4")) == 7);
+        CX_TEST_ASSERT(*((int*)cxMapGet(src, "k2")) == 9);
+        CX_TEST_ASSERT(*((int*)cxMapGet(src, "k5")) == 15);
+    }
+    cxMapFree(dst);
+    cxMapFree(src);
+}
+
 CX_TEST(test_hash_map_clone_ptr) {
     CxTestingAllocator talloc;
     cx_testing_allocator_init(&talloc);
@@ -571,6 +607,7 @@
     }
     CX_TEST_DO {
         int c = 4;
+        test_hash_map_clone_func_max_clones = 100; // no limit
         size_t cloned = cxMapClone(dst, src, test_hash_map_clone_func, allocator, &c);
         CX_TEST_ASSERT(cloned == 3);
         CX_TEST_ASSERT(cxMapSize(dst) == 5);
@@ -938,6 +975,7 @@
     cx_test_register(suite, test_hash_map_simple_destructor_pointers);
     cx_test_register(suite, test_hash_map_advanced_destructor_pointers);
     cx_test_register(suite, test_hash_map_clone);
+    cx_test_register(suite, test_hash_map_clone_alloc_fail);
     cx_test_register(suite, test_hash_map_clone_ptr);
     cx_test_register(suite, test_empty_map_no_ops);
     cx_test_register(suite, test_empty_map_size);