fix incorrect group ids in test (#14775)

Author: vporyadke

ydb/core/mind/hive/hive_ut.cpp

@@ -3000,14 +3000,6 @@ Y_UNIT_TEST_SUITE(THiveTest) {
 
     // Incorrect test, muted
     Y_UNIT_TEST(TestReassignUseRelativeSpace) {
-        // TODO: Remove this code after issue https://github.com/ydb-platform/ydb/issues/12255 will be resolved
-        ui64 prevSeed = NActors::DefaultRandomSeed;
-        NActors::DefaultRandomSeed = 42;
-        Y_SCOPE_EXIT(prevSeed) {
-            NActors::DefaultRandomSeed = prevSeed;
-        };
-        // TODO: Remove this code after issue https://github.com/ydb-platform/ydb/issues/12255 will be resolved
-
         TTestBasicRuntime runtime(1, false);
         Setup(runtime, true, 5);
         const ui64 hiveTablet = MakeDefaultHiveID();
@@ -3020,7 +3012,7 @@ Y_UNIT_TEST_SUITE(THiveTest) {
         MakeSureTabletIsUp(runtime, tabletId, 0);
 
         TActorId sender = runtime.AllocateEdgeActor();
-        std::unordered_set<ui32> otherPoolGroops;
+        std::unordered_set<ui32> unusedGroups;
         auto getGroup = [&runtime, sender, hiveTablet](ui64 tabletId) {
             runtime.SendToPipe(hiveTablet, sender, new TEvHive::TEvRequestHiveInfo({
                 .TabletId = tabletId,
@@ -3039,31 +3031,28 @@ Y_UNIT_TEST_SUITE(THiveTest) {
             THolder<TEvBlobStorage::TEvControllerSelectGroups> selectGroups = MakeHolder<TEvBlobStorage::TEvControllerSelectGroups>();
             NKikimrBlobStorage::TEvControllerSelectGroups& record = selectGroups->Record;
             record.SetReturnAllMatchingGroups(true);
-            std::vector<TString> storagePools = {"def2", "def3"}; // we will work with pool def1, so we want to avoid messing with other pools
-            for (const auto& pool : storagePools) {
-                record.AddGroupParameters()->MutableStoragePoolSpecifier()->SetName(pool);
-            }
+            record.AddGroupParameters()->MutableStoragePoolSpecifier()->SetName("def1");
             runtime.SendToPipe(MakeBSControllerID(), sender, selectGroups.Release());
             TAutoPtr<IEventHandle> handle;
             TEvBlobStorage::TEvControllerSelectGroupsResult* response = runtime.GrabEdgeEventRethrow<TEvBlobStorage::TEvControllerSelectGroupsResult>(handle);
             for (const auto& matchingGroups : response->Record.GetMatchingGroups()) {
                 for (const auto& group : matchingGroups.GetGroups()) {
-                    otherPoolGroops.insert(group.GetGroupID());
+                    unusedGroups.insert(group.GetGroupID());
                 }
             }
         }
 
-        auto getFreshGroup = [&otherPoolGroops](ui32 start) {
-            for (ui32 groupId = start + 1;; ++groupId) {
-                if (!otherPoolGroops.contains(groupId)) {
-                    return groupId;
-                }
-            }
+        auto getFreshGroup = [&unusedGroups]() {
+            UNIT_ASSERT(!unusedGroups.empty());
+            ui32 group = *unusedGroups.begin();
+            unusedGroups.erase(unusedGroups.begin());
+            return group;
         };
 
         ui32 initialGroup = getGroup(tabletId);
-        ui32 badGroup = getFreshGroup(initialGroup);
-        ui32 goodGroup = getFreshGroup(badGroup);
+        unusedGroups.erase(initialGroup);
+        ui32 badGroup = getFreshGroup();
+        ui32 goodGroup = getFreshGroup();
         Ctest << "Tablet is now in group " << initialGroup << ", should later move to " << goodGroup << Endl;
 
         struct TTestGroupInfo {