1 files changed, 12 insertions, 12 deletions
diff --git a/spec/ruby/core/string/swapcase_spec.rb b/spec/ruby/core/string/swapcase_spec.rb
index 417f6c6d8d..7f4c68366d 100644
--- a/spec/ruby/core/string/swapcase_spec.rb
+++ b/spec/ruby/core/string/swapcase_spec.rb
@@ -1,4 +1,5 @@
 # -*- encoding: utf-8 -*-
+# frozen_string_literal: false
 require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
 
@@ -9,6 +10,10 @@ describe "String#swapcase" do
    "+++---111222???".swapcase.should == "+++---111222???"
   end
 
+  it "returns a String in the same encoding as self" do
+    "Hello".encode("US-ASCII").swapcase.encoding.should == Encoding::US_ASCII
+  end
+
   describe "full Unicode case mapping" do
     it "works for all of Unicode with no option" do
       "äÖü".swapcase.should == "ÄöÜ"
@@ -28,6 +33,10 @@ describe "String#swapcase" do
     it "does not swapcase non-ASCII characters" do
       "aßet".swapcase(:ascii).should == "AßET"
     end
+
+    it "works with substrings" do
+      "prefix aTé"[-3..-1].swapcase(:ascii).should == "Até"
+    end
   end
 
   describe "full Unicode case mapping adapted for Turkic languages" do
@@ -66,18 +75,9 @@ describe "String#swapcase" do
     -> { "abc".swapcase(:invalid_option) }.should raise_error(ArgumentError)
   end
 
-  ruby_version_is ''...'3.0' do
-    it "returns subclass instances when called on a subclass" do
-      StringSpecs::MyString.new("").swapcase.should be_an_instance_of(StringSpecs::MyString)
-      StringSpecs::MyString.new("hello").swapcase.should be_an_instance_of(StringSpecs::MyString)
-    end
-  end
-
-  ruby_version_is '3.0' do
-    it "returns String instances when called on a subclass" do
-      StringSpecs::MyString.new("").swapcase.should be_an_instance_of(String)
-      StringSpecs::MyString.new("hello").swapcase.should be_an_instance_of(String)
-    end
+  it "returns String instances when called on a subclass" do
+    StringSpecs::MyString.new("").swapcase.should be_an_instance_of(String)
+    StringSpecs::MyString.new("hello").swapcase.should be_an_instance_of(String)
   end
 end