1 files changed, 193 insertions, 0 deletions
diff --git a/spec/ruby/core/string/swapcase_spec.rb b/spec/ruby/core/string/swapcase_spec.rb
new file mode 100644
index 0000000000..f0e6e0182c
--- /dev/null
+++ b/spec/ruby/core/string/swapcase_spec.rb
@@ -0,0 +1,193 @@
+# -*- 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???"
+  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"
+    end
+
+    it "updates string metadata" do
+      swapcased = "Aßet".swapcase
+
+      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
+
+    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
+    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 "does not allow any other additional option" do
+      -> { "aiS".swapcase(:turkic, :ascii) }.should.raise(ArgumentError)
+    end
+  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 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(:lithuanian, :ascii) }.should.raise(ArgumentError)
+    end
+  end
+
+  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.should == "CyBeR_pUnK11"
+  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
+
+  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 "works for non-ascii-compatible encodings" do
+      a = "äÖü".encode("utf-16le")
+      a.swapcase!
+      a.should == "ÄöÜ".encode("utf-16le")
+    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 ASCII-only case mapping" do
+    it "does not swapcase non-ASCII characters" do
+      a = "aßet"
+      a.swapcase!(:ascii)
+      a.should == "AßET"
+    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
+
+  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
+
+    it "allows Lithuanian as an extra option" do
+      a = "aiS"
+      a.swapcase!(:turkic, :lithuanian)
+      a.should == "Aİs"
+    end
+
+    it "does not allow any other additional option" do
+      -> { a = "aiS"; a.swapcase!(:turkic, :ascii) }.should.raise(ArgumentError)
+    end
+  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 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!(: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
+    a.should == "+++---111222???"
+
+    "".swapcase!.should == nil
+  end
+
+  it "raises a FrozenError when self is frozen" do
+    ["", "hello"].each do |a|
+      a.freeze
+      -> { a.swapcase! }.should.raise(FrozenError)
+    end
+  end
+end