diff --git a/test/models/room/messages_count_lifecycle_test.rb b/test/models/room/messages_count_lifecycle_test.rb
new file mode 100644
index 0000000..295e178
--- /dev/null
+++ b/test/models/room/messages_count_lifecycle_test.rb
@@ -0,0 +1,102 @@
+require "test_helper"
+require "sqlite3"
+
+# Destructive trigger DDL and foreign connections need their own file so parallel
+# workers (and transactional tests in messages_count_test) keep a stable trigger set.
+class Room::MessagesCountLifecycleTest < ActiveSupport::TestCase
+  self.use_transactional_tests = false
+
+  setup do
+    Room::MessagesCount.ensure!
+    @room = rooms(:designers)
+    @other_room = rooms(:pets)
+    Room::MessagesCount.backfill!
+    @room.reload
+    @other_room.reload
+  end
+
+  teardown do
+    Message.where("client_message_id LIKE ?", "count-%").delete_all
+    Room::MessagesCount.ensure!
+    Room::MessagesCount.backfill!
+  end
+
+  test "ensure! installs missing triggers without changing existing counts" do
+    before = @room.reload.messages_count
+    Room::MessagesCount.uninstall!
+
+    assert_not Room::MessagesCount.trigger_installed?(ActiveRecord::Base.connection, Room::MessagesCount::INSERT_TRIGGER)
+
+    Room::MessagesCount.ensure!
+
+    assert Room::MessagesCount::TRIGGERS.all? { |name|
+      Room::MessagesCount.trigger_installed?(ActiveRecord::Base.connection, name)
+    }
+    assert_equal before, @room.reload.messages_count
+
+    assert_difference -> { @room.reload.messages_count }, +1 do
+      @room.messages.create!(creator: users(:jason), body: "After ensure", client_message_id: "count-ensure")
+    end
+  end
+
+  test "ensure! repairs a partial trigger install" do
+    Room::MessagesCount.uninstall!
+    ActiveRecord::Base.connection.execute <<~SQL
+      CREATE TRIGGER #{Room::MessagesCount::INSERT_TRIGGER} AFTER INSERT ON messages
+      BEGIN
+        UPDATE rooms SET messages_count = messages_count + 1 WHERE id = NEW.room_id;
+      END
+    SQL
+
+    assert Room::MessagesCount.trigger_installed?(ActiveRecord::Base.connection, Room::MessagesCount::INSERT_TRIGGER)
+    assert_not Room::MessagesCount.trigger_installed?(ActiveRecord::Base.connection, Room::MessagesCount::DELETE_TRIGGER)
+
+    Room::MessagesCount.ensure!
+
+    assert Room::MessagesCount::TRIGGERS.all? { |name|
+      Room::MessagesCount.trigger_installed?(ActiveRecord::Base.connection, name)
+    }
+  end
+
+  test "foreign SQLite connections keep the counter in step" do
+    path = File.expand_path(ActiveRecord::Base.connection_db_config.database)
+    now = Time.current.utc.strftime("%Y-%m-%d %H:%M:%S.%6N")
+    before = @room.reload.messages_count
+    other_before = @other_room.reload.messages_count
+
+    ActiveRecord::Base.connection_pool.release_connection
+
+    SQLite3::Database.new(path) do |db|
+      db.busy_timeout = 5_000
+      db.execute(
+        "INSERT INTO messages (room_id, creator_id, client_message_id, created_at, updated_at) VALUES (?, ?, ?, ?, ?)",
+        [ @room.id, users(:david).id, "count-foreign-insert", now, now ]
+      )
+    end
+
+    assert_equal before + 1, @room.reload.messages_count
+    assert_equal @room.messages.count, @room.messages_count
+
+    foreign_id = Message.find_by!(client_message_id: "count-foreign-insert").id
+
+    ActiveRecord::Base.connection_pool.release_connection
+
+    SQLite3::Database.new(path) do |db|
+      db.busy_timeout = 5_000
+      db.execute("UPDATE messages SET room_id = ? WHERE id = ?", [ @other_room.id, foreign_id ])
+    end
+
+    assert_equal before, @room.reload.messages_count
+    assert_equal other_before + 1, @other_room.reload.messages_count
+
+    ActiveRecord::Base.connection_pool.release_connection
+
+    SQLite3::Database.new(path) do |db|
+      db.busy_timeout = 5_000
+      db.execute("DELETE FROM messages WHERE id = ?", [ foreign_id ])
+    end
+
+    assert_equal before, @room.reload.messages_count
+    assert_equal other_before, @other_room.reload.messages_count
+  end
+end
diff --git a/test/models/room/messages_count_test.rb b/test/models/room/messages_count_test.rb
index 911b21e..3b0e447 100644
--- a/test/models/room/messages_count_test.rb
+++ b/test/models/room/messages_count_test.rb
@@ -1,5 +1,4 @@
 require "test_helper"
-require "sqlite3"
 
 class Room::MessagesCountTest < ActiveSupport::TestCase
   setup do
@@ -85,102 +84,3 @@ class Room::MessagesCountTest < ActiveSupport::TestCase
     assert_not reflection.counter_cache_column
   end
 end
-
-# Destructive trigger DDL and foreign connections need a committed DB.
-class Room::MessagesCountLifecycleTest < ActiveSupport::TestCase
-  self.use_transactional_tests = false
-
-  setup do
-    Room::MessagesCount.ensure!
-    @room = rooms(:designers)
-    @other_room = rooms(:pets)
-    Room::MessagesCount.backfill!
-    @room.reload
-    @other_room.reload
-  end
-
-  teardown do
-    Message.where("client_message_id LIKE ?", "count-%").delete_all
-    Room::MessagesCount.ensure!
-    Room::MessagesCount.backfill!
-  end
-
-  test "ensure! installs missing triggers without changing existing counts" do
-    before = @room.reload.messages_count
-    Room::MessagesCount.uninstall!
-
-    assert_not Room::MessagesCount.trigger_installed?(ActiveRecord::Base.connection, Room::MessagesCount::INSERT_TRIGGER)
-
-    Room::MessagesCount.ensure!
-
-    assert Room::MessagesCount::TRIGGERS.all? { |name|
-      Room::MessagesCount.trigger_installed?(ActiveRecord::Base.connection, name)
-    }
-    assert_equal before, @room.reload.messages_count
-
-    assert_difference -> { @room.reload.messages_count }, +1 do
-      @room.messages.create!(creator: users(:jason), body: "After ensure", client_message_id: "count-ensure")
-    end
-  end
-
-  test "ensure! repairs a partial trigger install" do
-    Room::MessagesCount.uninstall!
-    ActiveRecord::Base.connection.execute <<~SQL
-      CREATE TRIGGER #{Room::MessagesCount::INSERT_TRIGGER} AFTER INSERT ON messages
-      BEGIN
-        UPDATE rooms SET messages_count = messages_count + 1 WHERE id = NEW.room_id;
-      END
-    SQL
-
-    assert Room::MessagesCount.trigger_installed?(ActiveRecord::Base.connection, Room::MessagesCount::INSERT_TRIGGER)
-    assert_not Room::MessagesCount.trigger_installed?(ActiveRecord::Base.connection, Room::MessagesCount::DELETE_TRIGGER)
-
-    Room::MessagesCount.ensure!
-
-    assert Room::MessagesCount::TRIGGERS.all? { |name|
-      Room::MessagesCount.trigger_installed?(ActiveRecord::Base.connection, name)
-    }
-  end
-
-  test "foreign SQLite connections keep the counter in step" do
-    path = File.expand_path(ActiveRecord::Base.connection_db_config.database)
-    now = Time.current.utc.strftime("%Y-%m-%d %H:%M:%S.%6N")
-    before = @room.reload.messages_count
-    other_before = @other_room.reload.messages_count
-
-    ActiveRecord::Base.connection_pool.release_connection
-
-    SQLite3::Database.new(path) do |db|
-      db.busy_timeout = 5_000
-      db.execute(
-        "INSERT INTO messages (room_id, creator_id, client_message_id, created_at, updated_at) VALUES (?, ?, ?, ?, ?)",
-        [ @room.id, users(:david).id, "count-foreign-insert", now, now ]
-      )
-    end
-
-    assert_equal before + 1, @room.reload.messages_count
-    assert_equal @room.messages.count, @room.messages_count
-
-    foreign_id = Message.find_by!(client_message_id: "count-foreign-insert").id
-
-    ActiveRecord::Base.connection_pool.release_connection
-
-    SQLite3::Database.new(path) do |db|
-      db.busy_timeout = 5_000
-      db.execute("UPDATE messages SET room_id = ? WHERE id = ?", [ @other_room.id, foreign_id ])
-    end
-
-    assert_equal before, @room.reload.messages_count
-    assert_equal other_before + 1, @other_room.reload.messages_count
-
-    ActiveRecord::Base.connection_pool.release_connection
-
-    SQLite3::Database.new(path) do |db|
-      db.busy_timeout = 5_000
-      db.execute("DELETE FROM messages WHERE id = ?", [ foreign_id ])
-    end
-
-    assert_equal before, @room.reload.messages_count
-    assert_equal other_before, @other_room.reload.messages_count
-  end
-end
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 6e3fa8b..30b87be 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -6,31 +6,15 @@ require "mocha/minitest"
 require "webmock/minitest"
 require "turbo/broadcastable/test_helper"
 
-# maintain_test_schema! may reload schema.rb after after_initialize; triggers are
-# not dumped, so ensure they exist before fixtures insert messages.
-Room::MessagesCount.ensure!
-
 WebMock.enable!
 
-module RoomMessagesCountFixtures
-  # Fixture YAML still inserts messages before rooms via some load paths, so
-  # INSERT triggers can update zero room rows. Reconcile once after load.
-  def load_fixtures(config)
-    fixtures = super
-    Room::MessagesCount.backfill!
-    fixtures
-  end
-end
-
 class ActiveSupport::TestCase
   include ActiveJob::TestHelper
-  prepend RoomMessagesCountFixtures
 
   parallelize(workers: :number_of_processors)
 
-  # Prefer rooms before messages when the loader honors declaration order.
-  fixtures :accounts, :users, :rooms, :memberships, :messages, "action_text/rich_texts",
-           :boosts, :searches, :sessions, :webhooks, "push/subscriptions"
+  # Setup all fixtures in test/fixtures/*.yml for all tests in alphabetical order.
+  fixtures :all
 
   include SessionTestHelper, MentionTestHelper, TurboTestHelper, DnsTestHelper
 
@@ -49,4 +33,13 @@ class ActiveSupport::TestCase
   teardown do
     WebMock.reset!
   end
+
+  # fixtures :all inserts messages before rooms, so INSERT triggers cannot count
+  # yet. Backfill once after load; ensure! covers schema.rb (triggers not dumped).
+  def load_fixtures(config)
+    fixtures = super
+    Room::MessagesCount.ensure!
+    Room::MessagesCount.backfill!
+    fixtures
+  end
 end