1 files changed, 32 insertions, 17 deletions

diff --git a/spec/ruby/core/string/downcase_spec.rb b/spec/ruby/core/string/downcase_spec.rb
index 9d57ea8e25..2d260f23f1 100644
--- a/spec/ruby/core/string/downcase_spec.rb
+++ b/spec/ruby/core/string/downcase_spec.rb
@@ -1,4 +1,5 @@
 # -*- encoding: utf-8 -*-
+# frozen_string_literal: false
 require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
 
@@ -8,6 +9,10 @@ describe "String#downcase" do
     "hello".downcase.should == "hello"
   end
 
+  it "returns a String in the same encoding as self" do
+    "hELLO".encode("US-ASCII").downcase.encoding.should == Encoding::US_ASCII
+  end
+
   describe "full Unicode case mapping" do
     it "works for all of Unicode with no option" do
       "ÄÖÜ".downcase.should == "äöü"
@@ -27,6 +32,10 @@ describe "String#downcase" do
     it "does not downcase non-ASCII characters" do
       "CÅR".downcase(:ascii).should == "cÅr"
     end
+
+    it "works with substrings" do
+      "prefix TÉ"[-2..-1].downcase(:ascii).should == "tÉ"
+    end
   end
 
   describe "full Unicode case mapping adapted for Turkic languages" do
@@ -39,7 +48,7 @@ describe "String#downcase" do
     end
 
     it "does not allow any other additional option" do
-      lambda { "İ".downcase(:turkic, :ascii) }.should raise_error(ArgumentError)
+      -> { "İ".downcase(:turkic, :ascii) }.should raise_error(ArgumentError)
     end
   end
 
@@ -53,7 +62,7 @@ describe "String#downcase" do
     end
 
     it "does not allow any other additional option" do
-      lambda { "İS".downcase(:lithuanian, :ascii) }.should raise_error(ArgumentError)
+      -> { "İS".downcase(:lithuanian, :ascii) }.should raise_error(ArgumentError)
     end
   end
 
@@ -65,17 +74,11 @@ describe "String#downcase" do
   end
 
   it "does not allow invalid options" do
-    lambda { "ABC".downcase(:invalid_option) }.should raise_error(ArgumentError)
-  end
-
-  it "taints result when self is tainted" do
-    "".taint.downcase.tainted?.should == true
-    "x".taint.downcase.tainted?.should == true
-    "X".taint.downcase.tainted?.should == true
+    -> { "ABC".downcase(:invalid_option) }.should raise_error(ArgumentError)
   end
 
-  it "returns a subclass instance for subclasses" do
-    StringSpecs::MyString.new("FOObar").downcase.should be_an_instance_of(StringSpecs::MyString)
+  it "returns a String instance for subclasses" do
+    StringSpecs::MyString.new("FOObar").downcase.should be_an_instance_of(String)
   end
 end
 
@@ -86,6 +89,12 @@ describe "String#downcase!" do
     a.should == "hello"
   end
 
+  it "modifies self in place for non-ascii-compatible encodings" do
+    a = "HeLlO".encode("utf-16le")
+    a.downcase!
+    a.should == "hello".encode("utf-16le")
+  end
+
   describe "full Unicode case mapping" do
     it "modifies self in place for all of Unicode with no option" do
       a = "ÄÖÜ"
@@ -110,6 +119,12 @@ describe "String#downcase!" do
       a.downcase!(:ascii)
       a.should == "cÅr"
     end
+
+    it "works for non-ascii-compatible encodings" do
+      a = "ABC".encode("utf-16le")
+      a.downcase!(:ascii)
+      a.should == "abc".encode("utf-16le")
+    end
   end
 
   describe "full Unicode case mapping adapted for Turkic languages" do
@@ -126,7 +141,7 @@ describe "String#downcase!" do
     end
 
     it "does not allow any other additional option" do
-      lambda { a = "İ"; a.downcase!(:turkic, :ascii) }.should raise_error(ArgumentError)
+      -> { a = "İ"; a.downcase!(:turkic, :ascii) }.should raise_error(ArgumentError)
     end
   end
 
@@ -144,7 +159,7 @@ describe "String#downcase!" do
     end
 
     it "does not allow any other additional option" do
-      lambda { a = "İS"; a.downcase!(:lithuanian, :ascii) }.should raise_error(ArgumentError)
+      -> { a = "İS"; a.downcase!(:lithuanian, :ascii) }.should raise_error(ArgumentError)
     end
   end
 
@@ -160,7 +175,7 @@ describe "String#downcase!" do
   end
 
   it "does not allow invalid options" do
-    lambda { a = "ABC"; a.downcase!(:invalid_option) }.should raise_error(ArgumentError)
+    -> { a = "ABC"; a.downcase!(:invalid_option) }.should raise_error(ArgumentError)
   end
 
   it "returns nil if no modifications were made" do
@@ -169,9 +184,9 @@ describe "String#downcase!" do
     a.should == "hello"
   end
 
-  it "raises a #{frozen_error_class} when self is frozen" do
-    lambda { "HeLlo".freeze.downcase! }.should raise_error(frozen_error_class)
-    lambda { "hello".freeze.downcase! }.should raise_error(frozen_error_class)
+  it "raises a FrozenError when self is frozen" do
+    -> { "HeLlo".freeze.downcase! }.should raise_error(FrozenError)
+    -> { "hello".freeze.downcase! }.should raise_error(FrozenError)
   end
 
   it "sets the result String encoding to the source String encoding" do