Add more database load balancing testss

ee/spec/lib/gitlab/database/load_balancing_spec.rb

@@ -583,6 +583,29 @@ RSpec.describe Gitlab::Database::LoadBalancing do
           false, [:replica, :replica]
         ],
 
+        # A custom read query inside use_replica_if_possible
+        [
+          -> {
+            ::Gitlab::Database::LoadBalancing::Session.current.use_replica_if_possible do
+              model.connection.exec_query("SELECT 1")
+            end
+          },
+          false, [:replica]
+        ],
+
+        # A custom read query inside a transaction use_replica_if_possible
+        [
+          -> {
+            ::Gitlab::Database::LoadBalancing::Session.current.use_replica_if_possible do
+              model.transaction do
+                model.connection.exec_query("SET LOCAL statement_timeout = 5000")
+                model.count
+              end
+            end
+          },
+          true, [:replica, :replica, :replica, :replica]
+        ],
+
         # use_replica_if_possible after a write
         [
           -> {

spec/models/application_record_spec.rb

@@ -120,7 +120,7 @@ RSpec.describe ApplicationRecord do
     # other way to test the timeout for sure, 10ms of waiting seems to be
     # reasonable!
     context 'when the query runs longer than configured timeout' do
-      it 'cancels the query and raiss an exception' do
+      it 'cancels the query and raises an exception' do
         expect do
           described_class.with_fast_read_statement_timeout(10) do
             described_class.connection.exec_query('SELECT pg_sleep(0.1)')