1 files changed, 19 insertions, 0 deletions
diff --git a/activerecord/test/cases/custom_locking_test.rb b/activerecord/test/cases/custom_locking_test.rb
new file mode 100644
index 0000000000..f52b26e9ec
--- /dev/null
+++ b/activerecord/test/cases/custom_locking_test.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/person"
+
+module ActiveRecord
+  class CustomLockingTest < ActiveRecord::TestCase
+    fixtures :people
+
+    def test_custom_lock
+      if current_adapter?(:Mysql2Adapter)
+        assert_match "SHARE MODE", Person.lock("LOCK IN SHARE MODE").to_sql
+        assert_sql(/LOCK IN SHARE MODE/) do
+          Person.all.merge!(lock: "LOCK IN SHARE MODE").find(1)
+        end
+      end
+    end
+  end
+end