diff --git a/activerecord/test/cases/encryption/extended_deterministic_queries_test.rb b/activerecord/test/cases/encryption/extended_deterministic_queries_test.rb
index fa4873faf5509..c7a3f984301e8 100644
--- a/activerecord/test/cases/encryption/extended_deterministic_queries_test.rb
+++ b/activerecord/test/cases/encryption/extended_deterministic_queries_test.rb
@@ -30,7 +30,7 @@ class ActiveRecord::Encryption::ExtendedDeterministicQueriesTest < ActiveRecord:
     assert EncryptedBook.find_by("name" => "Dune")
   end
 
-  test "find_or_create works" do
+  test "find_or_create_by works" do
     EncryptedBook.find_or_create_by!(name: "Dune")
     assert EncryptedBook.find_by(name: "Dune")
 
@@ -38,6 +38,13 @@ class ActiveRecord::Encryption::ExtendedDeterministicQueriesTest < ActiveRecord:
     assert EncryptedBook.find_by(name: "Dune")
   end
 
+  test "does not mutate arguments" do
+    props = { name: "Dune" }
+
+    assert_equal "Dune", EncryptedBook.find_or_initialize_by(props).name
+    assert_equal "Dune", props[:name]
+  end
+
   test "where(...).first_or_create works" do
     EncryptedBook.where(name: "Dune").first_or_create
     assert EncryptedBook.exists?(name: "Dune")