diff --git a/tests/configs/config-wrapper-malloc-0-null.h b/tests/configs/config-wrapper-malloc-0-null.h
new file mode 100644
index 0000000..ed74eda
--- /dev/null
+++ b/tests/configs/config-wrapper-malloc-0-null.h
@@ -0,0 +1,39 @@
+/* config.h wrapper that forces calloc(0) to return NULL.
+ * Used for testing.
+ */
+/*
+ *  Copyright (C) 2019, ARM Limited, All Rights Reserved
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *  This file is part of mbed TLS (https://tls.mbed.org)
+ */
+
+#ifndef MBEDTLS_CONFIG_H
+/* Don't #define MBEDTLS_CONFIG_H, let config.h do it. */
+
+#include "mbedtls/config.h"
+
+#include <stdlib.h>
+static inline void *custom_calloc( size_t nmemb, size_t size )
+{
+    if( nmemb == 0 || size == 0 )
+        return( NULL );
+    return( calloc( nmemb, size ) );
+}
+
+#define MBEDTLS_PLATFORM_MEMORY
+#define MBEDTLS_PLATFORM_STD_CALLOC custom_calloc
+
+#endif /* MBEDTLS_CONFIG_H */