5 files changed, 5 insertions, 5 deletions
diff --git a/railties/test/console_helpers.rb b/railties/test/console_helpers.rb
index 8350fce5ee..67f55fdc45 100644
--- a/railties/test/console_helpers.rb
+++ b/railties/test/console_helpers.rb
@@ -9,7 +9,7 @@ module ConsoleHelpers
   def assert_output(expected, io, timeout = 10)
     timeout = Time.now + timeout
 
-    output = "".dup
+    output = +""
     until output.include?(expected) || Time.now > timeout
       if IO.select([io], [], [], 0.1)
         output << io.read(1)
diff --git a/railties/test/generators/app_generator_test.rb b/railties/test/generators/app_generator_test.rb
index 14cdd8b5c9..1169633244 100644
--- a/railties/test/generators/app_generator_test.rb
+++ b/railties/test/generators/app_generator_test.rb
@@ -964,7 +964,7 @@ class AppGeneratorTest < Rails::Generators::TestCase
 
   def test_after_bundle_callback
     path = "http://example.org/rails_template"
-    template = %{ after_bundle { run 'echo ran after_bundle' } }.dup
+    template = +%{ after_bundle { run 'echo ran after_bundle' } }
     template.instance_eval "def read; self; end" # Make the string respond to read
 
     check_open = -> *args do
diff --git a/railties/test/generators/plugin_generator_test.rb b/railties/test/generators/plugin_generator_test.rb
index 20acd23329..468a9c9e89 100644
--- a/railties/test/generators/plugin_generator_test.rb
+++ b/railties/test/generators/plugin_generator_test.rb
@@ -737,7 +737,7 @@ class PluginGeneratorTest < Rails::Generators::TestCase
 
   def test_after_bundle_callback
     path = "http://example.org/rails_template"
-    template = %{ after_bundle { run "echo ran after_bundle" } }.dup
+    template = +%{ after_bundle { run "echo ran after_bundle" } }
     template.instance_eval "def read; self; end" # Make the string respond to read
 
     check_open = -> *args do
diff --git a/railties/test/generators/shared_generator_tests.rb b/railties/test/generators/shared_generator_tests.rb
index aa577e4234..5a1257e5c1 100644
--- a/railties/test/generators/shared_generator_tests.rb
+++ b/railties/test/generators/shared_generator_tests.rb
@@ -83,7 +83,7 @@ module SharedGeneratorTests
 
   def test_template_is_executed_when_supplied_an_https_path
     path = "https://gist.github.com/josevalim/103208/raw/"
-    template = %{ say "It works!" }.dup
+    template = +%{ say "It works!" }
     template.instance_eval "def read; self; end" # Make the string respond to read
 
     check_open = -> *args do
diff --git a/railties/test/isolation/abstract_unit.rb b/railties/test/isolation/abstract_unit.rb
index 96d21b3ae2..2a8c6d8f97 100644
--- a/railties/test/isolation/abstract_unit.rb
+++ b/railties/test/isolation/abstract_unit.rb
@@ -71,7 +71,7 @@ module TestHelpers
     end
 
     def extract_body(response)
-      "".dup.tap do |body|
+      (+"").tap do |body|
         response[2].each { |chunk| body << chunk }
       end
     end