diff --git a/tests/Makefile.am b/tests/Makefile.am
index 514a8497..78608f68 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -847,7 +847,8 @@ if OS_LINUX
 test_db_sync_integrity_SOURCES = test_db_sync_integrity.c
 test_db_sync_integrity_CFLAGS = -I$(top_srcdir)/src -I$(top_srcdir)/lib
 test_db_sync_integrity_LDADD = $(LIBUTUN) $(CRYPTO_LIBS) $(COMMON_LIBS)
-test_db_sync_integrity_LDFLAGS = -Wl,--wrap=EVP_DigestVerifyInit -Wl,--wrap=sqlite3_exec -Wl,--wrap=uasync_set_timeout
+test_db_sync_integrity_LDFLAGS = -Wl,--wrap=EVP_DigestVerifyInit -Wl,--wrap=sqlite3_exec -Wl,--wrap=uasync_set_timeout \
+    -Wl,--wrap=sqlite3_column_blob -Wl,--wrap=sqlite3_errcode
 endif
 
 test_merkle_sync_SOURCES = test_merkle_sync.c $(test_clock_sources)
diff --git a/tests/test_db_sync_integrity.c b/tests/test_db_sync_integrity.c
index 27d27556..d142368b 100644
--- a/tests/test_db_sync_integrity.c
+++ b/tests/test_db_sync_integrity.c
@@ -3,7 +3,7 @@
 #include "../src/chat/db_sync.c"
 #include <assert.h>
 
-static int fail_verify, fail_commit, fail_timer;
+static int fail_verify, fail_commit, fail_timer, fail_blob, blob_nomem;
 static unsigned fault_hits;
 extern int __real_EVP_DigestVerifyInit(EVP_MD_CTX*, EVP_PKEY_CTX**, const EVP_MD*, ENGINE*, EVP_PKEY*);
 int __wrap_EVP_DigestVerifyInit(EVP_MD_CTX* ctx, EVP_PKEY_CTX** pctx, const EVP_MD* md, ENGINE* engine, EVP_PKEY* key) {
@@ -17,6 +17,17 @@ int __wrap_sqlite3_exec(sqlite3* db, const char* sql, int (*cb)(void*, int, char
     return __real_sqlite3_exec(db, sql, cb, arg, err);
 }
 
+extern const void* __real_sqlite3_column_blob(sqlite3_stmt*, int);
+const void* __wrap_sqlite3_column_blob(sqlite3_stmt* stmt, int col) {
+    if (fail_blob) { fail_blob = 0; blob_nomem = 1; fault_hits++; return NULL; }
+    return __real_sqlite3_column_blob(stmt, col);
+}
+extern int __real_sqlite3_errcode(sqlite3*);
+int __wrap_sqlite3_errcode(sqlite3* db) {
+    if (blob_nomem) { blob_nomem = 0; return SQLITE_NOMEM; }
+    return __real_sqlite3_errcode(db);
+}
+
 extern void* __real_uasync_set_timeout(struct UASYNC*, uint64_t, void*, void (*)(void*), const char*);
 void* __wrap_uasync_set_timeout(struct UASYNC* ua, uint64_t delay, void* arg, void (*cb)(void*), const char* name) {
     if (fail_timer && !strcmp(name, "db_recalc")) { fail_timer = 0; fault_hits++; return NULL; }
@@ -84,10 +95,16 @@ static void test_preservation(void) {
     assert(insert(&f, 100, "original", sig) == 0 && insert(&f, 100, "original", sig) == 1);
     fail_verify = 1; assert(insert(&f, 100, "original", sig) == -1); intact(&f, "original");
     fail_verify = 2; assert(insert(&f, 100, "original", sig) == -1); intact(&f, "original");
+    fail_blob = 1; assert(insert(&f, 100, "original", sig) == -1); intact(&f, "original");
+    fail_blob = 1;
+    assert(si_send_data_batch(&f.si, 2, 0, 1, 0, DB_WANT_FROM_NONE) == -1); intact(&f, "original");
     assert(insert(&f, 100, "modified", sig) == -2); intact(&f, "original");
     sql(&f, "UPDATE history SET node_id=99");
     assert(insert(&f, 100, "original", sig) == -1); intact(&f, "original");
     assert(si_send_data_batch(&f.si, 2, 0, 1, 0, DB_WANT_FROM_NONE) == -1); intact(&f, "original");
+    f.inst.topo_sqlite_db = f.db.db; /* Отказ SQL lookup, в отличие от ещё неизвестного ключа. */
+    assert(insert(&f, 100, "original", sig) == -1); intact(&f, "original");
+    f.inst.topo_sqlite_db = NULL;
     sql(&f, "UPDATE history SET node_id=1");
     fail_verify = 1;
     assert(si_send_data_batch(&f.si, 2, 0, 1, 0, DB_WANT_FROM_NONE) == -1); intact(&f, "original");
@@ -134,6 +151,8 @@ static void test_recalc(void) {
     struct fixture f; init(&f); uint8_t sig[64];
     for (uint64_t ts = 1; ts <= 55; ts++) { sign(&f, ts, "record", sig); assert(insert(&f, ts, "record", sig) == 0); }
     uint64_t next = f.si.next_id, hash = 0;
+    fail_blob = 1;
+    assert(db_sync_last_chain_hash8(&f.si, &hash) == -1 && db_sync_count(&f.si) == 55 && f.si.recalc.pending);
     fail_commit = 1;
     assert(db_sync_last_chain_hash8(&f.si, &hash) == -1 && f.si.recalc.pending && f.si.recalc.pos == 0);
     assert(sqlite3_get_autocommit(f.db.db));
@@ -172,7 +191,7 @@ int main(void) {
     debug_config_init(); debug_set_level(DEBUG_LEVEL_WARN); debug_set_category_level(DEBUG_CATEGORY_CHAT_SYNC, DEBUG_LEVEL_DEBUG);
     size_t baseline = u_get_allocated_count();
     test_preservation(); test_deletion(); test_recalc(); test_delivery();
+    assert(fault_hits == 10 && u_get_allocated_count() == baseline);
     DEBUG_INFO(DEBUG_CATEGORY_CHAT_SYNC, "PASS history integrity; injected failures=%u; tracked allocations restored", fault_hits);
-    assert(fault_hits == 7 && u_get_allocated_count() == baseline);
     return 0;
 }