1 files changed, 38 insertions, 16 deletions
diff --git a/spec/ruby/core/string/sub_spec.rb b/spec/ruby/core/string/sub_spec.rb
index 9effe88c27..4f9f87a433 100644
--- a/spec/ruby/core/string/sub_spec.rb
+++ b/spec/ruby/core/string/sub_spec.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
 
@@ -170,22 +171,11 @@ describe "String#sub with pattern, replacement" do
     -> { "hello".sub(/[aeiou]/, 99) }.should raise_error(TypeError)
   end
 
-  ruby_version_is ''...'3.0' do
-    it "returns subclass instances when called on a subclass" do
-      StringSpecs::MyString.new("").sub(//, "").should be_an_instance_of(StringSpecs::MyString)
-      StringSpecs::MyString.new("").sub(/foo/, "").should be_an_instance_of(StringSpecs::MyString)
-      StringSpecs::MyString.new("foo").sub(/foo/, "").should be_an_instance_of(StringSpecs::MyString)
-      StringSpecs::MyString.new("foo").sub("foo", "").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("").sub(//, "").should be_an_instance_of(String)
-      StringSpecs::MyString.new("").sub(/foo/, "").should be_an_instance_of(String)
-      StringSpecs::MyString.new("foo").sub(/foo/, "").should be_an_instance_of(String)
-      StringSpecs::MyString.new("foo").sub("foo", "").should be_an_instance_of(String)
-    end
+  it "returns String instances when called on a subclass" do
+    StringSpecs::MyString.new("").sub(//, "").should be_an_instance_of(String)
+    StringSpecs::MyString.new("").sub(/foo/, "").should be_an_instance_of(String)
+    StringSpecs::MyString.new("foo").sub(/foo/, "").should be_an_instance_of(String)
+    StringSpecs::MyString.new("foo").sub("foo", "").should be_an_instance_of(String)
   end
 
   it "sets $~ to MatchData of match and nil when there's none" do
@@ -214,6 +204,17 @@ describe "String#sub with pattern, replacement" do
     "ababa".sub(/(b)/, '\\\\\1').should == "a\\baba"
   end
 
+  it "handles a pattern in a superset encoding" do
+    result = 'abc'.force_encoding(Encoding::US_ASCII).sub('é', 'è')
+    result.should == 'abc'
+    result.encoding.should == Encoding::US_ASCII
+  end
+
+  it "handles a pattern in a subset encoding" do
+    result = 'été'.sub('t'.force_encoding(Encoding::US_ASCII), 'u')
+    result.should == 'éué'
+    result.encoding.should == Encoding::UTF_8
+  end
 end
 
 describe "String#sub with pattern and block" do
@@ -299,6 +300,27 @@ describe "String#sub! with pattern, replacement" do
     -> { s.sub!(/e/, "e")       }.should raise_error(FrozenError)
     -> { s.sub!(/[aeiou]/, '*') }.should raise_error(FrozenError)
   end
+
+  it "handles a pattern in a superset encoding" do
+    string = 'abc'.force_encoding(Encoding::US_ASCII)
+
+    result = string.sub!('é', 'è')
+
+    result.should == nil
+    string.should == 'abc'
+    string.encoding.should == Encoding::US_ASCII
+  end
+
+  it "handles a pattern in a subset encoding" do
+    string = 'été'
+    pattern = 't'.force_encoding(Encoding::US_ASCII)
+
+    result = string.sub!(pattern, 'u')
+
+    result.should == string
+    string.should == 'éué'
+    string.encoding.should == Encoding::UTF_8
+  end
 end
 
 describe "String#sub! with pattern and block" do