1 files changed, 21 insertions, 0 deletions
diff --git a/spec/ruby/core/string/uminus_spec.rb b/spec/ruby/core/string/uminus_spec.rb
new file mode 100644
index 0000000000..53e73b7e67
--- /dev/null
+++ b/spec/ruby/core/string/uminus_spec.rb
@@ -0,0 +1,21 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+
+ruby_version_is "2.3" do
+  describe 'String#-@' do
+    it 'returns self if the String is frozen' do
+      input  = 'foo'.freeze
+      output = -input
+
+      output.equal?(input).should == true
+      output.frozen?.should == true
+    end
+
+    it 'returns a frozen copy if the String is not frozen' do
+      input  = 'foo'
+      output = -input
+
+      output.frozen?.should == true
+      output.should == 'foo'
+    end
+  end
+end