1 files changed, 70 insertions, 0 deletions
diff --git a/spec/ruby/core/string/reverse_spec.rb b/spec/ruby/core/string/reverse_spec.rb
new file mode 100644
index 0000000000..aa6abe6036
--- /dev/null
+++ b/spec/ruby/core/string/reverse_spec.rb
@@ -0,0 +1,70 @@
+# encoding: utf-8
+# frozen_string_literal: false
+
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+describe "String#reverse" do
+  it "returns a new string with the characters of self in reverse order" do
+    "stressed".reverse.should == "desserts"
+    "m".reverse.should == "m"
+    "".reverse.should == ""
+  end
+
+  it "returns String instances when called on a subclass" do
+    StringSpecs::MyString.new("stressed").reverse.should be_an_instance_of(String)
+    StringSpecs::MyString.new("m").reverse.should be_an_instance_of(String)
+    StringSpecs::MyString.new("").reverse.should be_an_instance_of(String)
+  end
+
+  it "reverses a string with multi byte characters" do
+    "微軟正黑體".reverse.should == "體黑正軟微"
+  end
+
+  it "works with a broken string" do
+    str = "微軟\xDF\xDE正黑體".force_encoding(Encoding::UTF_8)
+
+    str.valid_encoding?.should be_false
+
+    str.reverse.should == "體黑正\xDE\xDF軟微"
+  end
+
+  it "returns a String in the same encoding as self" do
+    "stressed".encode("US-ASCII").reverse.encoding.should == Encoding::US_ASCII
+  end
+end
+
+describe "String#reverse!" do
+  it "reverses self in place and always returns self" do
+    a = "stressed"
+    a.reverse!.should equal(a)
+    a.should == "desserts"
+
+    "".reverse!.should == ""
+  end
+
+  it "raises a FrozenError on a frozen instance that is modified" do
+    -> { "anna".freeze.reverse!  }.should raise_error(FrozenError)
+    -> { "hello".freeze.reverse! }.should raise_error(FrozenError)
+  end
+
+  # see [ruby-core:23666]
+  it "raises a FrozenError on a frozen instance that would not be modified" do
+    -> { "".freeze.reverse! }.should raise_error(FrozenError)
+  end
+
+  it "reverses a string with multi byte characters" do
+    str = "微軟正黑體"
+    str.reverse!
+    str.should == "體黑正軟微"
+  end
+
+  it "works with a broken string" do
+    str = "微軟\xDF\xDE正黑體".force_encoding(Encoding::UTF_8)
+
+    str.valid_encoding?.should be_false
+    str.reverse!
+
+    str.should == "體黑正\xDE\xDF軟微"
+  end
+end