Add a test case for OOM while allocating memory

test/suites/api/test_memory_funcs.c

@@ -5,8 +5,9 @@
 
 static int malloc_called = 0;
 static int free_called = 0;
+static size_t malloc_used = 0;
 
-/* helper */
+/* helpers */
 static void create_and_free_complex_object()
 {
     json_t *obj;
@@ -22,6 +23,20 @@ static void create_and_free_complex_object()
     json_decref(obj);
 }
 
+static void create_and_free_object_with_oom()
+{
+    json_t *obj = json_object();
+
+    for (int i = 0; i < 10; i++)
+    {
+        char key[4];
+        snprintf(key, sizeof key, "%d", i);
+        json_object_set_new(obj, key, json_integer(i));
+    }
+
+    json_decref(obj);
+}
+
 static void *my_malloc(size_t size)
 {
     malloc_called = 1;
@@ -49,6 +64,32 @@ static void test_simple()
 }
 
 
+static void *oom_malloc(size_t size)
+{
+    if (malloc_used + size > 800)
+        return NULL;
+
+    malloc_used += size;
+    return malloc(size);
+}
+
+static void oom_free(void *ptr)
+{
+    free_called++;
+    free(ptr);
+}
+
+static void test_oom()
+{
+    free_called = 0;
+    json_set_alloc_funcs(oom_malloc, oom_free);
+    create_and_free_object_with_oom();
+
+    if (free_called == 0)
+        fail("Allocation with OOM failed");
+}
+
+
 /*
   Test the secure memory functions code given in the API reference
   documentation, but by using plain memset instead of
@@ -84,4 +125,5 @@ static void run_tests()
 {
     test_simple();
     test_secure_funcs();
+    test_oom();
 }