1 files changed, 24 insertions, 0 deletions
diff --git a/spec/ruby/core/string/uplus_spec.rb b/spec/ruby/core/string/uplus_spec.rb
new file mode 100644
index 0000000000..eafa721903
--- /dev/null
+++ b/spec/ruby/core/string/uplus_spec.rb
@@ -0,0 +1,24 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+
+ruby_version_is "2.3" do
+  describe 'String#+@' do
+    it 'returns an unfrozen copy of a frozen String' do
+      input  = 'foo'.freeze
+      output = +input
+
+      output.frozen?.should == false
+      output.should == 'foo'
+    end
+
+    it 'returns self if the String is not frozen' do
+      input  = 'foo'
+      output = +input
+
+      output.equal?(input).should == true
+    end
+
+    it 'returns mutable copy despite freeze-magic-comment in file' do
+      ruby_exe(fixture(__FILE__, "freeze_magic_comment.rb")).should == 'mutable'
+    end
+  end
+end