Enforce frozen string in Rubocop

68 files changed, 68 insertions, 0 deletions

diff --git a/activerecord/test/cases/adapters/mysql2/active_schema_test.rb b/activerecord/test/cases/adapters/mysql2/active_schema_test.rb
index 67e1efde27..fdf83aaf88 100644
--- a/activerecord/test/cases/adapters/mysql2/active_schema_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/active_schema_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/connection_helper"
 
diff --git a/activerecord/test/cases/adapters/mysql2/bind_parameter_test.rb b/activerecord/test/cases/adapters/mysql2/bind_parameter_test.rb
index 8f7c803a21..9f3d1459f7 100644
--- a/activerecord/test/cases/adapters/mysql2/bind_parameter_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/bind_parameter_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "models/topic"
 
diff --git a/activerecord/test/cases/adapters/mysql2/boolean_test.rb b/activerecord/test/cases/adapters/mysql2/boolean_test.rb
index 58698d59db..9267d15def 100644
--- a/activerecord/test/cases/adapters/mysql2/boolean_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/boolean_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 class Mysql2BooleanTest < ActiveRecord::Mysql2TestCase
diff --git a/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb b/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb
index 50ba9ab831..65dc369213 100644
--- a/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 class Mysql2CaseSensitivityTest < ActiveRecord::Mysql2TestCase
diff --git a/activerecord/test/cases/adapters/mysql2/charset_collation_test.rb b/activerecord/test/cases/adapters/mysql2/charset_collation_test.rb
index e4a6ed5482..e77f4a90d4 100644
--- a/activerecord/test/cases/adapters/mysql2/charset_collation_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/charset_collation_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/mysql2/connection_test.rb b/activerecord/test/cases/adapters/mysql2/connection_test.rb
index a2faf43b0d..c5ff145e74 100644
--- a/activerecord/test/cases/adapters/mysql2/connection_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/connection_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/connection_helper"
 
diff --git a/activerecord/test/cases/adapters/mysql2/datetime_precision_quoting_test.rb b/activerecord/test/cases/adapters/mysql2/datetime_precision_quoting_test.rb
index c131a5169c..86e72c149c 100644
--- a/activerecord/test/cases/adapters/mysql2/datetime_precision_quoting_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/datetime_precision_quoting_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 class Mysql2DatetimePrecisionQuotingTest < ActiveRecord::Mysql2TestCase
diff --git a/activerecord/test/cases/adapters/mysql2/enum_test.rb b/activerecord/test/cases/adapters/mysql2/enum_test.rb
index 7ad3e3ca2d..b811179c1b 100644
--- a/activerecord/test/cases/adapters/mysql2/enum_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/enum_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 class Mysql2EnumTest < ActiveRecord::Mysql2TestCase
diff --git a/activerecord/test/cases/adapters/mysql2/explain_test.rb b/activerecord/test/cases/adapters/mysql2/explain_test.rb
index 7916921e5a..84c15af08d 100644
--- a/activerecord/test/cases/adapters/mysql2/explain_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/explain_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "models/developer"
 require "models/computer"
diff --git a/activerecord/test/cases/adapters/mysql2/json_test.rb b/activerecord/test/cases/adapters/mysql2/json_test.rb
index 26c69edc7b..2d39db4ce2 100644
--- a/activerecord/test/cases/adapters/mysql2/json_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/json_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "cases/json_shared_test_cases"
 
diff --git a/activerecord/test/cases/adapters/mysql2/mysql2_adapter_test.rb b/activerecord/test/cases/adapters/mysql2/mysql2_adapter_test.rb
index 565130c38f..7ba388bee1 100644
--- a/activerecord/test/cases/adapters/mysql2/mysql2_adapter_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/mysql2_adapter_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/ddl_helper"
 
diff --git a/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb b/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb
index 251a50e41e..4a421e2b91 100644
--- a/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 class SchemaMigrationsTest < ActiveRecord::Mysql2TestCase
diff --git a/activerecord/test/cases/adapters/mysql2/schema_test.rb b/activerecord/test/cases/adapters/mysql2/schema_test.rb
index 1fad5585de..c4bf58c13e 100644
--- a/activerecord/test/cases/adapters/mysql2/schema_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/schema_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "models/post"
 require "models/comment"
diff --git a/activerecord/test/cases/adapters/mysql2/sp_test.rb b/activerecord/test/cases/adapters/mysql2/sp_test.rb
index 4182532535..d4c4d02f79 100644
--- a/activerecord/test/cases/adapters/mysql2/sp_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/sp_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "models/topic"
 require "models/reply"
diff --git a/activerecord/test/cases/adapters/mysql2/sql_types_test.rb b/activerecord/test/cases/adapters/mysql2/sql_types_test.rb
index d6e7f29a5c..c412166451 100644
--- a/activerecord/test/cases/adapters/mysql2/sql_types_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/sql_types_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 class Mysql2SqlTypesTest < ActiveRecord::Mysql2TestCase
diff --git a/activerecord/test/cases/adapters/mysql2/table_options_test.rb b/activerecord/test/cases/adapters/mysql2/table_options_test.rb
index 61a8ce9bc0..54da2195d1 100644
--- a/activerecord/test/cases/adapters/mysql2/table_options_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/table_options_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/mysql2/transaction_test.rb b/activerecord/test/cases/adapters/mysql2/transaction_test.rb
index 16101e38cb..e447e6ec83 100644
--- a/activerecord/test/cases/adapters/mysql2/transaction_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/transaction_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/connection_helper"
 
diff --git a/activerecord/test/cases/adapters/mysql2/unsigned_type_test.rb b/activerecord/test/cases/adapters/mysql2/unsigned_type_test.rb
index 71dcfaa241..1703e8fef7 100644
--- a/activerecord/test/cases/adapters/mysql2/unsigned_type_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/unsigned_type_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/mysql2/virtual_column_test.rb b/activerecord/test/cases/adapters/mysql2/virtual_column_test.rb
index 442a4fb7b5..85e283bfe1 100644
--- a/activerecord/test/cases/adapters/mysql2/virtual_column_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/virtual_column_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/active_schema_test.rb b/activerecord/test/cases/adapters/postgresql/active_schema_test.rb
index b787de8453..441e84a117 100644
--- a/activerecord/test/cases/adapters/postgresql/active_schema_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/active_schema_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 class PostgresqlActiveSchemaTest < ActiveRecord::PostgreSQLTestCase
diff --git a/activerecord/test/cases/adapters/postgresql/array_test.rb b/activerecord/test/cases/adapters/postgresql/array_test.rb
index 121c62dadf..a642145726 100644
--- a/activerecord/test/cases/adapters/postgresql/array_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/array_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/bit_string_test.rb b/activerecord/test/cases/adapters/postgresql/bit_string_test.rb
index 7712e809a2..d7ed0aa8dd 100644
--- a/activerecord/test/cases/adapters/postgresql/bit_string_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/bit_string_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/connection_helper"
 require "support/schema_dumping_helper"
diff --git a/activerecord/test/cases/adapters/postgresql/bytea_test.rb b/activerecord/test/cases/adapters/postgresql/bytea_test.rb
index 539c90f0bc..7cb5c2442c 100644
--- a/activerecord/test/cases/adapters/postgresql/bytea_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/bytea_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/case_insensitive_test.rb b/activerecord/test/cases/adapters/postgresql/case_insensitive_test.rb
index 03b44feab6..b6db6e5e28 100644
--- a/activerecord/test/cases/adapters/postgresql/case_insensitive_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/case_insensitive_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 class PostgresqlCaseInsensitiveTest < ActiveRecord::PostgreSQLTestCase
diff --git a/activerecord/test/cases/adapters/postgresql/change_schema_test.rb b/activerecord/test/cases/adapters/postgresql/change_schema_test.rb
index ea642069d2..9d7fddfc02 100644
--- a/activerecord/test/cases/adapters/postgresql/change_schema_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/change_schema_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 module ActiveRecord
diff --git a/activerecord/test/cases/adapters/postgresql/cidr_test.rb b/activerecord/test/cases/adapters/postgresql/cidr_test.rb
index 52f2a0096c..fccd8b3c7b 100644
--- a/activerecord/test/cases/adapters/postgresql/cidr_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/cidr_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "ipaddr"
 
diff --git a/activerecord/test/cases/adapters/postgresql/citext_test.rb b/activerecord/test/cases/adapters/postgresql/citext_test.rb
index ca95e4b626..ffdd2983c6 100644
--- a/activerecord/test/cases/adapters/postgresql/citext_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/citext_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/collation_test.rb b/activerecord/test/cases/adapters/postgresql/collation_test.rb
index a603221d8f..2929c9ad94 100644
--- a/activerecord/test/cases/adapters/postgresql/collation_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/collation_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/composite_test.rb b/activerecord/test/cases/adapters/postgresql/composite_test.rb
index 1da2a9e2ac..9eb422a8a3 100644
--- a/activerecord/test/cases/adapters/postgresql/composite_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/composite_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/connection_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/connection_test.rb b/activerecord/test/cases/adapters/postgresql/connection_test.rb
index 32afe331fa..3adae7e146 100644
--- a/activerecord/test/cases/adapters/postgresql/connection_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/connection_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/connection_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/datatype_test.rb b/activerecord/test/cases/adapters/postgresql/datatype_test.rb
index 0725fde5ae..f947868898 100644
--- a/activerecord/test/cases/adapters/postgresql/datatype_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/datatype_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/ddl_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/domain_test.rb b/activerecord/test/cases/adapters/postgresql/domain_test.rb
index f1eb8adb15..b16e0f9265 100644
--- a/activerecord/test/cases/adapters/postgresql/domain_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/domain_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/connection_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/enum_test.rb b/activerecord/test/cases/adapters/postgresql/enum_test.rb
index 5e5a3158ba..0f8ab8ab23 100644
--- a/activerecord/test/cases/adapters/postgresql/enum_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/enum_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/connection_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/explain_test.rb b/activerecord/test/cases/adapters/postgresql/explain_test.rb
index d79fbccf47..8a0cf440fd 100644
--- a/activerecord/test/cases/adapters/postgresql/explain_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/explain_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "models/developer"
 require "models/computer"
diff --git a/activerecord/test/cases/adapters/postgresql/extension_migration_test.rb b/activerecord/test/cases/adapters/postgresql/extension_migration_test.rb
index b56c226763..ba2b4e1fbf 100644
--- a/activerecord/test/cases/adapters/postgresql/extension_migration_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/extension_migration_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 class PostgresqlExtensionMigrationTest < ActiveRecord::PostgreSQLTestCase
diff --git a/activerecord/test/cases/adapters/postgresql/full_text_test.rb b/activerecord/test/cases/adapters/postgresql/full_text_test.rb
index 5ddfe32007..fa8aadd224 100644
--- a/activerecord/test/cases/adapters/postgresql/full_text_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/full_text_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/geometric_test.rb b/activerecord/test/cases/adapters/postgresql/geometric_test.rb
index 3b6840a1c9..34836b2421 100644
--- a/activerecord/test/cases/adapters/postgresql/geometric_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/geometric_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/connection_helper"
 require "support/schema_dumping_helper"
diff --git a/activerecord/test/cases/adapters/postgresql/hstore_test.rb b/activerecord/test/cases/adapters/postgresql/hstore_test.rb
index f9cce10fb8..b547868b57 100644
--- a/activerecord/test/cases/adapters/postgresql/hstore_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/hstore_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/infinity_test.rb b/activerecord/test/cases/adapters/postgresql/infinity_test.rb
index b9e177e6ec..df5c688881 100644
--- a/activerecord/test/cases/adapters/postgresql/infinity_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/infinity_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 class PostgresqlInfinityTest < ActiveRecord::PostgreSQLTestCase
diff --git a/activerecord/test/cases/adapters/postgresql/integer_test.rb b/activerecord/test/cases/adapters/postgresql/integer_test.rb
index b4e55964b9..5557e869ad 100644
--- a/activerecord/test/cases/adapters/postgresql/integer_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/integer_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "active_support/core_ext/numeric/bytes"
 
diff --git a/activerecord/test/cases/adapters/postgresql/json_test.rb b/activerecord/test/cases/adapters/postgresql/json_test.rb
index 6aa60630c2..4438f349cc 100644
--- a/activerecord/test/cases/adapters/postgresql/json_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/json_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "cases/json_shared_test_cases"
 
diff --git a/activerecord/test/cases/adapters/postgresql/ltree_test.rb b/activerecord/test/cases/adapters/postgresql/ltree_test.rb
index 2b5ac1cac6..447d68316c 100644
--- a/activerecord/test/cases/adapters/postgresql/ltree_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/ltree_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/money_test.rb b/activerecord/test/cases/adapters/postgresql/money_test.rb
index 1b5d8362af..530aeb0c29 100644
--- a/activerecord/test/cases/adapters/postgresql/money_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/money_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/network_test.rb b/activerecord/test/cases/adapters/postgresql/network_test.rb
index a33b0ef8a7..2bbfb292c4 100644
--- a/activerecord/test/cases/adapters/postgresql/network_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/network_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/numbers_test.rb b/activerecord/test/cases/adapters/postgresql/numbers_test.rb
index bfb2b7c27a..82edf7db3f 100644
--- a/activerecord/test/cases/adapters/postgresql/numbers_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/numbers_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 class PostgresqlNumberTest < ActiveRecord::PostgreSQLTestCase
diff --git a/activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb b/activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb
index 76e0ad60fe..7c7bb0a942 100644
--- a/activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/ddl_helper"
 require "support/connection_helper"
diff --git a/activerecord/test/cases/adapters/postgresql/prepared_statements_disabled_test.rb b/activerecord/test/cases/adapters/postgresql/prepared_statements_disabled_test.rb
index 8c62690866..0120e33f70 100644
--- a/activerecord/test/cases/adapters/postgresql/prepared_statements_disabled_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/prepared_statements_disabled_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "models/computer"
 require "models/developer"
diff --git a/activerecord/test/cases/adapters/postgresql/quoting_test.rb b/activerecord/test/cases/adapters/postgresql/quoting_test.rb
index a1e966b915..1205559558 100644
--- a/activerecord/test/cases/adapters/postgresql/quoting_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/quoting_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 module ActiveRecord
diff --git a/activerecord/test/cases/adapters/postgresql/range_test.rb b/activerecord/test/cases/adapters/postgresql/range_test.rb
index f411884dfd..8de162a8a1 100644
--- a/activerecord/test/cases/adapters/postgresql/range_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/range_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/connection_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/referential_integrity_test.rb b/activerecord/test/cases/adapters/postgresql/referential_integrity_test.rb
index 0ff04bfa27..0b17c141c8 100644
--- a/activerecord/test/cases/adapters/postgresql/referential_integrity_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/referential_integrity_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/connection_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/rename_table_test.rb b/activerecord/test/cases/adapters/postgresql/rename_table_test.rb
index e9e7f717ac..5b253999d5 100644
--- a/activerecord/test/cases/adapters/postgresql/rename_table_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/rename_table_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 class PostgresqlRenameTableTest < ActiveRecord::PostgreSQLTestCase
diff --git a/activerecord/test/cases/adapters/postgresql/schema_authorization_test.rb b/activerecord/test/cases/adapters/postgresql/schema_authorization_test.rb
index f86a76e08a..db7d8ba751 100644
--- a/activerecord/test/cases/adapters/postgresql/schema_authorization_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/schema_authorization_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 class SchemaThing < ActiveRecord::Base
diff --git a/activerecord/test/cases/adapters/postgresql/schema_test.rb b/activerecord/test/cases/adapters/postgresql/schema_test.rb
index f6b957476b..5438665d42 100644
--- a/activerecord/test/cases/adapters/postgresql/schema_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/schema_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "models/default"
 require "support/schema_dumping_helper"
diff --git a/activerecord/test/cases/adapters/postgresql/serial_test.rb b/activerecord/test/cases/adapters/postgresql/serial_test.rb
index d711b3b729..4930d3f67a 100644
--- a/activerecord/test/cases/adapters/postgresql/serial_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/serial_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/statement_pool_test.rb b/activerecord/test/cases/adapters/postgresql/statement_pool_test.rb
index 146b619a4b..73cf91425b 100644
--- a/activerecord/test/cases/adapters/postgresql/statement_pool_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/statement_pool_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 module ActiveRecord
diff --git a/activerecord/test/cases/adapters/postgresql/timestamp_test.rb b/activerecord/test/cases/adapters/postgresql/timestamp_test.rb
index 962450aada..c7dec25f3a 100644
--- a/activerecord/test/cases/adapters/postgresql/timestamp_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/timestamp_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "models/developer"
 require "models/topic"
diff --git a/activerecord/test/cases/adapters/postgresql/transaction_test.rb b/activerecord/test/cases/adapters/postgresql/transaction_test.rb
index 9b42d0383d..c1b19c11f5 100644
--- a/activerecord/test/cases/adapters/postgresql/transaction_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/transaction_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/connection_helper"
 require "concurrent/atomic/cyclic_barrier"
diff --git a/activerecord/test/cases/adapters/postgresql/type_lookup_test.rb b/activerecord/test/cases/adapters/postgresql/type_lookup_test.rb
index 784d77a8d1..688117722b 100644
--- a/activerecord/test/cases/adapters/postgresql/type_lookup_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/type_lookup_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 class PostgresqlTypeLookupTest < ActiveRecord::PostgreSQLTestCase
diff --git a/activerecord/test/cases/adapters/postgresql/utils_test.rb b/activerecord/test/cases/adapters/postgresql/utils_test.rb
index 9f9e3bda2f..1a655d7843 100644
--- a/activerecord/test/cases/adapters/postgresql/utils_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/utils_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "active_record/connection_adapters/postgresql/utils"
 
diff --git a/activerecord/test/cases/adapters/postgresql/uuid_test.rb b/activerecord/test/cases/adapters/postgresql/uuid_test.rb
index 8eddd81c38..49c570c917 100644
--- a/activerecord/test/cases/adapters/postgresql/uuid_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/uuid_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/postgresql/xml_test.rb b/activerecord/test/cases/adapters/postgresql/xml_test.rb
index 826b384fb3..b0720b5a6e 100644
--- a/activerecord/test/cases/adapters/postgresql/xml_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/xml_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/sqlite3/collation_test.rb b/activerecord/test/cases/adapters/sqlite3/collation_test.rb
index dd88ed3656..f3cbb408f1 100644
--- a/activerecord/test/cases/adapters/sqlite3/collation_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/collation_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "support/schema_dumping_helper"
 
diff --git a/activerecord/test/cases/adapters/sqlite3/copy_table_test.rb b/activerecord/test/cases/adapters/sqlite3/copy_table_test.rb
index e1cfd703e8..cc1f74ed41 100644
--- a/activerecord/test/cases/adapters/sqlite3/copy_table_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/copy_table_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 class CopyTableTest < ActiveRecord::SQLite3TestCase
diff --git a/activerecord/test/cases/adapters/sqlite3/explain_test.rb b/activerecord/test/cases/adapters/sqlite3/explain_test.rb
index 29d97ae78c..a3f6299756 100644
--- a/activerecord/test/cases/adapters/sqlite3/explain_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/explain_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "models/developer"
 require "models/computer"
diff --git a/activerecord/test/cases/adapters/sqlite3/quoting_test.rb b/activerecord/test/cases/adapters/sqlite3/quoting_test.rb
index aefbb309e6..0a5bf7754c 100644
--- a/activerecord/test/cases/adapters/sqlite3/quoting_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/quoting_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "bigdecimal"
 require "securerandom"
diff --git a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
index 9a812e325e..7adba54836 100644
--- a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "models/owner"
 require "tempfile"
diff --git a/activerecord/test/cases/adapters/sqlite3/sqlite3_create_folder_test.rb b/activerecord/test/cases/adapters/sqlite3/sqlite3_create_folder_test.rb
index b1b4463bf1..d23a7ac532 100644
--- a/activerecord/test/cases/adapters/sqlite3/sqlite3_create_folder_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/sqlite3_create_folder_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 require "models/owner"
 
diff --git a/activerecord/test/cases/adapters/sqlite3/statement_pool_test.rb b/activerecord/test/cases/adapters/sqlite3/statement_pool_test.rb
index 37ff973397..76841c235a 100644
--- a/activerecord/test/cases/adapters/sqlite3/statement_pool_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/statement_pool_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cases/helper"
 
 class SQLite3StatementPoolTest < ActiveRecord::SQLite3TestCase