diff --git a/tests/db_sync_fixture.h b/tests/db_sync_fixture.h
new file mode 100644
index 00000000..928a5b58
--- /dev/null
+++ b/tests/db_sync_fixture.h
@@ -0,0 +1,31 @@
+/* Модель истории для тестов с заранее заданными участниками, без запуска chat_sync.
+ * Общий Merkle настоящий; пустая MEMBERS-модель не реплицирует тестовые удостоверения.
+ * Если движок создан фикстурой (!chat_sync), перед destroy ядра вызвать merkle_sync_destroy. */
+#ifndef TEST_DB_SYNC_FIXTURE_H
+#define TEST_DB_SYNC_FIXTURE_H
+#include "../src/utun_instance.h"
+#include "../src/transport_layer/etcp_api.h"
+#include "../src/chat/db_sync.h"
+#include "../src/chat/merkle_sync.h"
+#include <string.h>
+
+static int fixture_member_hash(void* ctx, const char* ns, uint8_t level, uint64_t prefix, EVP_MD_CTX* hash) {
+    (void)ctx; (void)ns; (void)level; (void)prefix; (void)hash; return 0;
+}
+static int fixture_member_page(void* ctx, const char* ns, uint64_t prefix, int av, const merkle_key_t* after,
+        uint8_t* data, size_t* len, merkle_key_t* next, int* more) {
+    (void)ctx; (void)ns; (void)prefix; (void)av; (void)after; (void)data;
+    *len = 0; *more = 0; memset(next, 0, sizeof(*next)); return 0;
+}
+static int fixture_member_apply(void* ctx, const char* ns, uint64_t peer, const uint8_t* data, size_t len) {
+    (void)ctx; (void)ns; (void)peer; (void)data; return len ? -1 : 0;
+}
+/* После init ядра и регистрации таблиц; 0/-1. READY/допуск пира/подписи истории не подменяются. */
+static int setup_history_model(struct UTUN_INSTANCE* inst) {
+    static const struct merkle_sync_data_ops ops = {
+        .update_bucket_hash = fixture_member_hash, .get_page = fixture_member_page, .apply_items = fixture_member_apply
+    };
+    if (!inst->msync && merkle_sync_init(inst, ETCP_ID_MEMBER_SYNC, &ops, inst) < 0) return -1;
+    return db_sync_register_model(inst);
+}
+#endif
diff --git a/tests/test_chat_sync_stress.c b/tests/test_chat_sync_stress.c
index b632ee95..6884b926 100644
--- a/tests/test_chat_sync_stress.c
+++ b/tests/test_chat_sync_stress.c
@@ -7,6 +7,7 @@
 #include "../lib/platform_compat.h"
 #include "test_utils.h"
 #include "test_net.h"
+#include "db_sync_fixture.h"
 #ifdef _WIN32
 #include <windows.h>
 #include <direct.h>
@@ -174,6 +175,9 @@ int main(void) {
     si_a = db_sync_instance_add(inst_a, INSTANCE_NAME, INSTANCE_ID);
     si_b = db_sync_instance_add(inst_b, INSTANCE_NAME, INSTANCE_ID);
     if (!si_a || !si_b) { DEBUG_ERROR(DEBUG_CATEGORY_DEBUG, "db_sync_instance_add"); return 1; }
+    if (setup_history_model(inst_a) < 0 || setup_history_model(inst_b) < 0) {
+        DEBUG_ERROR(DEBUG_CATEGORY_DEBUG, "history model registration"); return 1;
+    }
     db_sync_instance_set_gated(si_a, 0); db_sync_instance_set_gated(si_b, 0);
     timeout_id = uasync_set_timeout(ua, TOTAL_TIMEOUT_TB, NULL, test_timeout, "total_timeout");
 
@@ -257,8 +261,8 @@ cleanup:
     if (timeout_id && ua) { uasync_cancel_timeout(ua, timeout_id); timeout_id = NULL; }
     if (si_a) { db_sync_instance_remove(si_a); si_a = NULL; }
     if (si_b) { db_sync_instance_remove(si_b); si_b = NULL; }
-    if (inst_a) { inst_a->running = 0; utun_instance_destroy(inst_a); inst_a = NULL; }
-    if (inst_b) { inst_b->running = 0; utun_instance_destroy(inst_b); inst_b = NULL; }
+    if (inst_a) { inst_a->running = 0; if (!inst_a->chat_sync) merkle_sync_destroy(inst_a); utun_instance_destroy(inst_a); inst_a = NULL; }
+    if (inst_b) { inst_b->running = 0; if (!inst_b->chat_sync) merkle_sync_destroy(inst_b); utun_instance_destroy(inst_b); inst_b = NULL; }
     if (ua) { uasync_destroy(ua, 0); ua = NULL; }
     debug_disable_file_output();
 
diff --git a/tests/test_db_sync.c b/tests/test_db_sync.c
index 60d4894d..d7943c9c 100644
--- a/tests/test_db_sync.c
+++ b/tests/test_db_sync.c
@@ -8,6 +8,7 @@
 #include "../lib/platform_compat.h"
 #include "test_utils.h"
 #include "test_net.h"
+#include "db_sync_fixture.h"
 #ifdef _WIN32
 #include <windows.h>
 #include <direct.h>
@@ -247,25 +248,6 @@ static struct DB_SYNC_INSTANCE* add_table(struct UTUN_INSTANCE* inst, const char
 }
 
 
-/* Изолируем модель истории от протокола MEMBERS; настоящие групповые READY и транспорт не подменяются. */
-static int empty_hash(void* ctx, const char* ns, uint8_t level, uint64_t prefix, EVP_MD_CTX* hash) {
-    (void)ctx; (void)ns; (void)level; (void)prefix; (void)hash; return 0;
-}
-static int empty_page(void* ctx, const char* ns, uint64_t prefix, int av, const merkle_key_t* after,
-        uint8_t* data, size_t* len, merkle_key_t* next, int* more) {
-    (void)ctx; (void)ns; (void)prefix; (void)av; (void)after; (void)data;
-    *len = 0; *more = 0; memset(next, 0, sizeof(*next)); return 0;
-}
-static int empty_apply(void* ctx, const char* ns, uint64_t peer, const uint8_t* data, size_t len) {
-    (void)ctx; (void)ns; (void)peer; (void)data; return len ? -1 : 0;
-}
-static int setup_history_model(struct UTUN_INSTANCE* inst) {
-    static const struct merkle_sync_data_ops ops = {
-        .update_bucket_hash = empty_hash, .get_page = empty_page, .apply_items = empty_apply
-    };
-    if (!inst->msync && merkle_sync_init(inst, ETCP_ID_MEMBER_SYNC, &ops, inst) < 0) return -1;
-    return db_sync_register_model(inst);
-}
 static int history_ready(struct DB_SYNC_INSTANCE* si) { uint8_t root[32]; return db_sync_read_root(si, root); }
 static int same_roots(struct DB_SYNC_INSTANCE* a, struct DB_SYNC_INSTANCE* b, struct DB_SYNC_INSTANCE* c) {
     uint8_t ra[32], rb[32], rc[32];