tests: Verify the right implementation is used

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Sahana Prasad <sahana@redhat.com>

tests/external_override/sntrup761_override.c

@@ -0,0 +1,73 @@
+/*
+ * This file is part of the SSH Library
+ *
+ * Copyright (c) 2021 - 2025 Red Hat, Inc.
+ *
+ * Authors: Anderson Toshiyuki Sasaki
+ *          Jakub Jelen <jjelen@redhat.com>
+ *
+ * The SSH Library is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * The SSH Library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with the SSH Library; see the file COPYING. If not,
+ * see <https://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <libssh/priv.h>
+#include <libssh/sntrup761.h>
+
+#include "sntrup761_override.h"
+
+static bool internal_function_called = false;
+
+void __wrap_sntrup761_keypair(uint8_t *pk,
+                              uint8_t *sk,
+                              void *random_ctx,
+                              sntrup761_random_func *random)
+{
+    fprintf(stderr, "%s: Internal implementation was called\n", __func__);
+    internal_function_called = true;
+    return sntrup761_keypair(pk, sk, random_ctx, random);
+}
+
+void __wrap_sntrup761_enc(uint8_t *c,
+                          uint8_t *k,
+                          const uint8_t *pk,
+                          void *random_ctx,
+                          sntrup761_random_func *random)
+{
+    fprintf(stderr, "%s: Internal implementation was called\n", __func__);
+    internal_function_called = true;
+    return sntrup761_enc(c, k, pk, random_ctx, random);
+}
+
+void __wrap_sntrup761_dec(uint8_t *k, const uint8_t *c, const uint8_t *sk)
+{
+    fprintf(stderr, "%s: Internal implementation was called\n", __func__);
+    internal_function_called = true;
+    return sntrup761_dec(k, c, sk);
+}
+
+bool internal_sntrup761_function_called(void)
+{
+    return internal_function_called;
+}
+
+void reset_sntrup761_function_called(void)
+{
+    internal_function_called = false;
+}