1 files changed, 123 insertions, 113 deletions
diff --git a/spec/ruby/core/string/swapcase_spec.rb b/spec/ruby/core/string/swapcase_spec.rb
index bb89dee48f..f0e6e0182c 100644
--- a/spec/ruby/core/string/swapcase_spec.rb
+++ b/spec/ruby/core/string/swapcase_spec.rb
@@ -1,171 +1,181 @@
 # -*- encoding: utf-8 -*-
+# frozen_string_literal: false
 require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
 
 describe "String#swapcase" do
   it "returns a new string with all uppercase chars from self converted to lowercase and vice versa" do
-   "Hello".swapcase.should == "hELLO"
-   "cYbEr_PuNk11".swapcase.should == "CyBeR_pUnK11"
-   "+++---111222???".swapcase.should == "+++---111222???"
+    "Hello".swapcase.should == "hELLO"
+    "cYbEr_PuNk11".swapcase.should == "CyBeR_pUnK11"
+    "+++---111222???".swapcase.should == "+++---111222???"
   end
 
-  it "taints resulting string when self is tainted" do
-    "".taint.swapcase.tainted?.should == true
-    "hello".taint.swapcase.tainted?.should == true
+  it "returns a String in the same encoding as self" do
+    "Hello".encode("US-ASCII").swapcase.encoding.should == Encoding::US_ASCII
   end
 
-  ruby_version_is ''...'2.4' do
-    it "is locale insensitive (only upcases a-z and only downcases A-Z)" do
-      "ÄÖÜ".swapcase.should == "ÄÖÜ"
-      "ärger".swapcase.should == "äRGER"
-      "BÄR".swapcase.should == "bÄr"
+  describe "full Unicode case mapping" do
+    it "works for all of Unicode with no option" do
+      "äÖü".swapcase.should == "ÄöÜ"
     end
-  end
-
-  ruby_version_is '2.4' do
-    describe "full Unicode case mapping" do
-      it "works for all of Unicode with no option" do
-        "äÖü".swapcase.should == "ÄöÜ"
-      end
 
-      it "updates string metadata" do
-        swapcased = "Aßet".swapcase
+    it "updates string metadata" do
+      swapcased = "Aßet".swapcase
 
-        swapcased.should == "aSSET"
-        swapcased.size.should == 5
-        swapcased.bytesize.should == 5
-        swapcased.ascii_only?.should be_true
-      end
+      swapcased.should == "aSSET"
+      swapcased.size.should == 5
+      swapcased.bytesize.should == 5
+      swapcased.ascii_only?.should == true
     end
+  end
 
-    describe "ASCII-only case mapping" do
-      it "does not swapcase non-ASCII characters" do
-        "aßet".swapcase(:ascii).should == "AßET"
-      end
+  describe "ASCII-only case mapping" do
+    it "does not swapcase non-ASCII characters" do
+      "aßet".swapcase(:ascii).should == "AßET"
     end
 
-    describe "full Unicode case mapping adapted for Turkic languages" do
-      it "swaps case of ASCII characters according to Turkic semantics" do
-        "aiS".swapcase(:turkic).should == "Aİs"
-      end
-
-      it "allows Lithuanian as an extra option" do
-        "aiS".swapcase(:turkic, :lithuanian).should == "Aİs"
-      end
+    it "works with substrings" do
+      "prefix aTé"[-3..-1].swapcase(:ascii).should == "Até"
+    end
+  end
 
-      it "does not allow any other additional option" do
-        lambda { "aiS".swapcase(:turkic, :ascii) }.should raise_error(ArgumentError)
-      end
+  describe "full Unicode case mapping adapted for Turkic languages" do
+    it "swaps case of ASCII characters according to Turkic semantics" do
+      "aiS".swapcase(:turkic).should == "Aİs"
     end
 
-    describe "full Unicode case mapping adapted for Lithuanian" do
-      it "currently works the same as full Unicode case mapping" do
-        "Iß".swapcase(:lithuanian).should == "iSS"
-      end
+    it "allows Lithuanian as an extra option" do
+      "aiS".swapcase(:turkic, :lithuanian).should == "Aİs"
+    end
 
-      it "allows Turkic as an extra option (and applies Turkic semantics)" do
-        "iS".swapcase(:lithuanian, :turkic).should == "İs"
-      end
+    it "does not allow any other additional option" do
+      -> { "aiS".swapcase(:turkic, :ascii) }.should.raise(ArgumentError)
+    end
+  end
 
-      it "does not allow any other additional option" do
-        lambda { "aiS".swapcase(:lithuanian, :ascii) }.should raise_error(ArgumentError)
-      end
+  describe "full Unicode case mapping adapted for Lithuanian" do
+    it "currently works the same as full Unicode case mapping" do
+      "Iß".swapcase(:lithuanian).should == "iSS"
     end
 
-    it "does not allow the :fold option for upcasing" do
-      lambda { "abc".swapcase(:fold) }.should raise_error(ArgumentError)
+    it "allows Turkic as an extra option (and applies Turkic semantics)" do
+      "iS".swapcase(:lithuanian, :turkic).should == "İs"
     end
 
-    it "does not allow invalid options" do
-      lambda { "abc".swapcase(:invalid_option) }.should raise_error(ArgumentError)
+    it "does not allow any other additional option" do
+      -> { "aiS".swapcase(:lithuanian, :ascii) }.should.raise(ArgumentError)
     end
   end
 
-  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)
+  it "does not allow the :fold option for upcasing" do
+    -> { "abc".swapcase(:fold) }.should.raise(ArgumentError)
+  end
+
+  it "does not allow invalid options" do
+    -> { "abc".swapcase(:invalid_option) }.should.raise(ArgumentError)
+  end
+
+  it "returns String instances when called on a subclass" do
+    StringSpecs::MyString.new("").swapcase.should.instance_of?(String)
+    StringSpecs::MyString.new("hello").swapcase.should.instance_of?(String)
   end
 end
 
 describe "String#swapcase!" do
   it "modifies self in place" do
     a = "cYbEr_PuNk11"
-    a.swapcase!.should equal(a)
+    a.swapcase!.should.equal?(a)
     a.should == "CyBeR_pUnK11"
   end
 
-  ruby_version_is '2.4' do
-    describe "full Unicode case mapping" do
-      it "modifies self in place for all of Unicode with no option" do
-        a = "äÖü"
-        a.swapcase!
-        a.should == "ÄöÜ"
-      end
+  it "modifies self in place for non-ascii-compatible encodings" do
+    a = "cYbEr_PuNk11".encode("utf-16le")
+    a.swapcase!
+    a.should == "CyBeR_pUnK11".encode("utf-16le")
+  end
 
-      it "updates string metadata" do
-        swapcased = "Aßet"
-        swapcased.swapcase!
+  describe "full Unicode case mapping" do
+    it "modifies self in place for all of Unicode with no option" do
+      a = "äÖü"
+      a.swapcase!
+      a.should == "ÄöÜ"
+    end
 
-        swapcased.should == "aSSET"
-        swapcased.size.should == 5
-        swapcased.bytesize.should == 5
-        swapcased.ascii_only?.should be_true
-      end
+    it "works for non-ascii-compatible encodings" do
+      a = "äÖü".encode("utf-16le")
+      a.swapcase!
+      a.should == "ÄöÜ".encode("utf-16le")
     end
 
-    describe "modifies self in place for ASCII-only case mapping" do
-      it "does not swapcase non-ASCII characters" do
-        a = "aßet"
-        a.swapcase!(:ascii)
-        a.should == "AßET"
-      end
+    it "updates string metadata" do
+      swapcased = "Aßet"
+      swapcased.swapcase!
+
+      swapcased.should == "aSSET"
+      swapcased.size.should == 5
+      swapcased.bytesize.should == 5
+      swapcased.ascii_only?.should == true
     end
+  end
 
-    describe "modifies self in place for full Unicode case mapping adapted for Turkic languages" do
-      it "swaps case of ASCII characters according to Turkic semantics" do
-        a = "aiS"
-        a.swapcase!(:turkic)
-        a.should == "Aİs"
-      end
+  describe "modifies self in place for ASCII-only case mapping" do
+    it "does not swapcase non-ASCII characters" do
+      a = "aßet"
+      a.swapcase!(:ascii)
+      a.should == "AßET"
+    end
 
-      it "allows Lithuanian as an extra option" do
-        a = "aiS"
-        a.swapcase!(:turkic, :lithuanian)
-        a.should == "Aİs"
-      end
+    it "works for non-ascii-compatible encodings" do
+      a = "aBc".encode("utf-16le")
+      a.swapcase!(:ascii)
+      a.should == "AbC".encode("utf-16le")
+    end
+  end
 
-      it "does not allow any other additional option" do
-        lambda { a = "aiS"; a.swapcase!(:turkic, :ascii) }.should raise_error(ArgumentError)
-      end
+  describe "modifies self in place for full Unicode case mapping adapted for Turkic languages" do
+    it "swaps case of ASCII characters according to Turkic semantics" do
+      a = "aiS"
+      a.swapcase!(:turkic)
+      a.should == "Aİs"
     end
 
-    describe "full Unicode case mapping adapted for Lithuanian" do
-      it "currently works the same as full Unicode case mapping" do
-        a = "Iß"
-        a.swapcase!(:lithuanian)
-        a.should == "iSS"
-      end
+    it "allows Lithuanian as an extra option" do
+      a = "aiS"
+      a.swapcase!(:turkic, :lithuanian)
+      a.should == "Aİs"
+    end
 
-      it "allows Turkic as an extra option (and applies Turkic semantics)" do
-        a = "iS"
-        a.swapcase!(:lithuanian, :turkic)
-        a.should == "İs"
-      end
+    it "does not allow any other additional option" do
+      -> { a = "aiS"; a.swapcase!(:turkic, :ascii) }.should.raise(ArgumentError)
+    end
+  end
 
-      it "does not allow any other additional option" do
-        lambda { a = "aiS"; a.swapcase!(:lithuanian, :ascii) }.should raise_error(ArgumentError)
-      end
+  describe "full Unicode case mapping adapted for Lithuanian" do
+    it "currently works the same as full Unicode case mapping" do
+      a = "Iß"
+      a.swapcase!(:lithuanian)
+      a.should == "iSS"
     end
 
-    it "does not allow the :fold option for upcasing" do
-      lambda { a = "abc"; a.swapcase!(:fold) }.should raise_error(ArgumentError)
+    it "allows Turkic as an extra option (and applies Turkic semantics)" do
+      a = "iS"
+      a.swapcase!(:lithuanian, :turkic)
+      a.should == "İs"
     end
 
-    it "does not allow invalid options" do
-      lambda { a = "abc"; a.swapcase!(:invalid_option) }.should raise_error(ArgumentError)
+    it "does not allow any other additional option" do
+      -> { a = "aiS"; a.swapcase!(:lithuanian, :ascii) }.should.raise(ArgumentError)
     end
   end
 
+  it "does not allow the :fold option for upcasing" do
+    -> { a = "abc"; a.swapcase!(:fold) }.should.raise(ArgumentError)
+  end
+
+  it "does not allow invalid options" do
+    -> { a = "abc"; a.swapcase!(:invalid_option) }.should.raise(ArgumentError)
+  end
+
   it "returns nil if no modifications were made" do
     a = "+++---111222???"
     a.swapcase!.should == nil
@@ -174,10 +184,10 @@ describe "String#swapcase!" do
     "".swapcase!.should == nil
   end
 
-  it "raises a #{frozen_error_class} when self is frozen" do
+  it "raises a FrozenError when self is frozen" do
     ["", "hello"].each do |a|
       a.freeze
-      lambda { a.swapcase! }.should raise_error(frozen_error_class)
+      -> { a.swapcase! }.should.raise(FrozenError)
     end
   end
 end