1 files changed, 38 insertions, 0 deletions
diff --git a/activemodel/test/cases/type/string_test.rb b/activemodel/test/cases/type/string_test.rb
new file mode 100644
index 0000000000..2d85556d20
--- /dev/null
+++ b/activemodel/test/cases/type/string_test.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveModel
+  module Type
+    class StringTest < ActiveModel::TestCase
+      test "type casting" do
+        type = Type::String.new
+        assert_equal "t", type.cast(true)
+        assert_equal "f", type.cast(false)
+        assert_equal "123", type.cast(123)
+      end
+
+      test "cast strings are mutable" do
+        type = Type::String.new
+
+        s = +"foo"
+        assert_equal false, type.cast(s).frozen?
+        assert_equal false, s.frozen?
+
+        f = -"foo"
+        assert_equal false, type.cast(f).frozen?
+        assert_equal true, f.frozen?
+      end
+
+      test "values are duped coming out" do
+        type = Type::String.new
+
+        s = "foo"
+        assert_not_same s, type.cast(s)
+        assert_equal s, type.cast(s)
+        assert_not_same s, type.deserialize(s)
+        assert_equal s, type.deserialize(s)
+      end
+    end
+  end
+end