13 files changed, 27 insertions, 14 deletions
diff --git a/activemodel/test/cases/type/big_integer_test.rb b/activemodel/test/cases/type/big_integer_test.rb
index 56002b7cc6..0fa0200df4 100644
--- a/activemodel/test/cases/type/big_integer_test.rb
+++ b/activemodel/test/cases/type/big_integer_test.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
+
 require "cases/helper"
-require "active_model/type"
 
 module ActiveModel
   module Type
diff --git a/activemodel/test/cases/type/binary_test.rb b/activemodel/test/cases/type/binary_test.rb
index e9c2ccfca4..3221a73e49 100644
--- a/activemodel/test/cases/type/binary_test.rb
+++ b/activemodel/test/cases/type/binary_test.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
+
 require "cases/helper"
-require "active_model/type"
 
 module ActiveModel
   module Type
diff --git a/activemodel/test/cases/type/boolean_test.rb b/activemodel/test/cases/type/boolean_test.rb
index 92e5aebfb7..2d33579595 100644
--- a/activemodel/test/cases/type/boolean_test.rb
+++ b/activemodel/test/cases/type/boolean_test.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
+
 require "cases/helper"
-require "active_model/type"
 
 module ActiveModel
   module Type
diff --git a/activemodel/test/cases/type/date_test.rb b/activemodel/test/cases/type/date_test.rb
index 0cc90e99d3..e8cf178612 100644
--- a/activemodel/test/cases/type/date_test.rb
+++ b/activemodel/test/cases/type/date_test.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
+
 require "cases/helper"
-require "active_model/type"
 
 module ActiveModel
   module Type
diff --git a/activemodel/test/cases/type/date_time_test.rb b/activemodel/test/cases/type/date_time_test.rb
index 75a7fc686e..60f62becc2 100644
--- a/activemodel/test/cases/type/date_time_test.rb
+++ b/activemodel/test/cases/type/date_time_test.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
+
 require "cases/helper"
-require "active_model/type"
 
 module ActiveModel
   module Type
diff --git a/activemodel/test/cases/type/decimal_test.rb b/activemodel/test/cases/type/decimal_test.rb
index c3b43725cc..b91d67f95f 100644
--- a/activemodel/test/cases/type/decimal_test.rb
+++ b/activemodel/test/cases/type/decimal_test.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
+
 require "cases/helper"
-require "active_model/type"
 
 module ActiveModel
   module Type
diff --git a/activemodel/test/cases/type/float_test.rb b/activemodel/test/cases/type/float_test.rb
index 8026d63ad5..28318e06f8 100644
--- a/activemodel/test/cases/type/float_test.rb
+++ b/activemodel/test/cases/type/float_test.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
+
 require "cases/helper"
-require "active_model/type"
 
 module ActiveModel
   module Type
diff --git a/activemodel/test/cases/type/immutable_string_test.rb b/activemodel/test/cases/type/immutable_string_test.rb
index 23e58974fb..751f753ddb 100644
--- a/activemodel/test/cases/type/immutable_string_test.rb
+++ b/activemodel/test/cases/type/immutable_string_test.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
+
 require "cases/helper"
-require "active_model/type"
 
 module ActiveModel
   module Type
diff --git a/activemodel/test/cases/type/integer_test.rb b/activemodel/test/cases/type/integer_test.rb
index a91144036b..8c5d18c9b3 100644
--- a/activemodel/test/cases/type/integer_test.rb
+++ b/activemodel/test/cases/type/integer_test.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
+
 require "cases/helper"
-require "active_model/type"
 require "active_support/core_ext/numeric/time"
 
 module ActiveModel
diff --git a/activemodel/test/cases/type/registry_test.rb b/activemodel/test/cases/type/registry_test.rb
index 927b6d0307..0633ea2538 100644
--- a/activemodel/test/cases/type/registry_test.rb
+++ b/activemodel/test/cases/type/registry_test.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
+
 require "cases/helper"
-require "active_model/type"
 
 module ActiveModel
   module Type
diff --git a/activemodel/test/cases/type/string_test.rb b/activemodel/test/cases/type/string_test.rb
index 47d412e27e..825c8bb246 100644
--- a/activemodel/test/cases/type/string_test.rb
+++ b/activemodel/test/cases/type/string_test.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
+
 require "cases/helper"
-require "active_model/type"
 
 module ActiveModel
   module Type
@@ -14,7 +15,7 @@ module ActiveModel
       test "cast strings are mutable" do
         type = Type::String.new
 
-        s = "foo"
+        s = "foo".dup
         assert_equal false, type.cast(s).frozen?
         assert_equal false, s.frozen?
 
diff --git a/activemodel/test/cases/type/time_test.rb b/activemodel/test/cases/type/time_test.rb
index 0cc4d33caa..f7102d1e97 100644
--- a/activemodel/test/cases/type/time_test.rb
+++ b/activemodel/test/cases/type/time_test.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
+
 require "cases/helper"
-require "active_model/type"
 
 module ActiveModel
   module Type
diff --git a/activemodel/test/cases/type/value_test.rb b/activemodel/test/cases/type/value_test.rb
index d8b3e7f164..55b5d9d584 100644
--- a/activemodel/test/cases/type/value_test.rb
+++ b/activemodel/test/cases/type/value_test.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
+
 require "cases/helper"
-require "active_model/type"
 
 module ActiveModel
   module Type