3 files changed, 6 insertions, 6 deletions
diff --git a/activesupport/test/cache/behaviors/cache_store_behavior.rb b/activesupport/test/cache/behaviors/cache_store_behavior.rb
index e17c09ba39..f7c750c08e 100644
--- a/activesupport/test/cache/behaviors/cache_store_behavior.rb
+++ b/activesupport/test/cache/behaviors/cache_store_behavior.rb
@@ -319,7 +319,7 @@ module CacheStoreBehavior
   end
 
   def test_original_store_objects_should_not_be_immutable
-    bar = "bar".dup
+    bar = +"bar"
     @cache.write("foo", bar)
     assert_nothing_raised { bar.gsub!(/.*/, "baz") }
   end
diff --git a/activesupport/test/cache/behaviors/encoded_key_cache_behavior.rb b/activesupport/test/cache/behaviors/encoded_key_cache_behavior.rb
index da16142496..842400f4a3 100644
--- a/activesupport/test/cache/behaviors/encoded_key_cache_behavior.rb
+++ b/activesupport/test/cache/behaviors/encoded_key_cache_behavior.rb
@@ -6,7 +6,7 @@
 module EncodedKeyCacheBehavior
   Encoding.list.each do |encoding|
     define_method "test_#{encoding.name.underscore}_encoded_values" do
-      key = "foo".dup.force_encoding(encoding)
+      key = (+"foo").force_encoding(encoding)
       assert @cache.write(key, "1", raw: true)
       assert_equal "1", @cache.read(key)
       assert_equal "1", @cache.fetch(key)
@@ -18,7 +18,7 @@ module EncodedKeyCacheBehavior
   end
 
   def test_common_utf8_values
-    key = "\xC3\xBCmlaut".dup.force_encoding(Encoding::UTF_8)
+    key = (+"\xC3\xBCmlaut").force_encoding(Encoding::UTF_8)
     assert @cache.write(key, "1", raw: true)
     assert_equal "1", @cache.read(key)
     assert_equal "1", @cache.fetch(key)
@@ -29,7 +29,7 @@ module EncodedKeyCacheBehavior
   end
 
   def test_retains_encoding
-    key = "\xC3\xBCmlaut".dup.force_encoding(Encoding::UTF_8)
+    key = (+"\xC3\xBCmlaut").force_encoding(Encoding::UTF_8)
     assert @cache.write(key, "1", raw: true)
     assert_equal Encoding::UTF_8, key.encoding
   end
diff --git a/activesupport/test/cache/cache_key_test.rb b/activesupport/test/cache/cache_key_test.rb
index 84e656f504..c2240d03c2 100644
--- a/activesupport/test/cache/cache_key_test.rb
+++ b/activesupport/test/cache/cache_key_test.rb
@@ -47,7 +47,7 @@ class CacheKeyTest < ActiveSupport::TestCase
   end
 
   def test_expand_cache_key_respond_to_cache_key
-    key = "foo".dup
+    key = +"foo"
     def key.cache_key
       :foo_key
     end
@@ -55,7 +55,7 @@ class CacheKeyTest < ActiveSupport::TestCase
   end
 
   def test_expand_cache_key_array_with_something_that_responds_to_cache_key
-    key = "foo".dup
+    key = +"foo"
     def key.cache_key
       :foo_key
     end