1 files changed, 108 insertions, 0 deletions
diff --git a/spec/rubyspec/core/string/comparison_spec.rb b/spec/rubyspec/core/string/comparison_spec.rb
new file mode 100644
index 0000000000..5a0e7fabc3
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+++ b/spec/rubyspec/core/string/comparison_spec.rb
@@ -0,0 +1,108 @@
+# -*- encoding: utf-8 -*-
+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes.rb', __FILE__)
+
+describe "String#<=> with String" do
+  it "compares individual characters based on their ascii value" do
+    ascii_order = Array.new(256) { |x| x.chr }
+    sort_order = ascii_order.sort
+    sort_order.should == ascii_order
+  end
+
+  it "returns -1 when self is less than other" do
+    ("this" <=> "those").should == -1
+  end
+
+  it "returns 0 when self is equal to other" do
+    ("yep" <=> "yep").should == 0
+  end
+
+  it "returns 1 when self is greater than other" do
+    ("yoddle" <=> "griddle").should == 1
+  end
+
+  it "considers string that comes lexicographically first to be less if strings have same size" do
+    ("aba" <=> "abc").should == -1
+    ("abc" <=> "aba").should == 1
+  end
+
+  it "doesn't consider shorter string to be less if longer string starts with shorter one" do
+    ("abc" <=> "abcd").should == -1
+    ("abcd" <=> "abc").should == 1
+  end
+
+  it "compares shorter string with corresponding number of first chars of longer string" do
+    ("abx" <=> "abcd").should == 1
+    ("abcd" <=> "abx").should == -1
+  end
+
+  it "ignores subclass differences" do
+    a = "hello"
+    b = StringSpecs::MyString.new("hello")
+
+    (a <=> b).should == 0
+    (b <=> a).should == 0
+  end
+
+  it "returns 0 if self and other are bytewise identical and have the same encoding" do
+    ("ÄÖÜ" <=> "ÄÖÜ").should == 0
+  end
+
+  it "returns 0 if self and other are bytewise identical and have the same encoding" do
+    ("ÄÖÜ" <=> "ÄÖÜ").should == 0
+  end
+
+  it "returns -1 if self is bytewise less than other" do
+    ("ÄÖÛ" <=> "ÄÖÜ").should == -1
+  end
+
+  it "returns 1 if self is bytewise greater than other" do
+    ("ÄÖÜ" <=> "ÄÖÛ").should == 1
+  end
+
+  it "ignores encoding difference" do
+    ("ÄÖÛ".force_encoding("utf-8") <=> "ÄÖÜ".force_encoding("iso-8859-1")).should == -1
+    ("ÄÖÜ".force_encoding("utf-8") <=> "ÄÖÛ".force_encoding("iso-8859-1")).should == 1
+  end
+
+  it "returns 0 with identical ASCII-compatible bytes of different encodings" do
+    ("abc".force_encoding("utf-8") <=> "abc".force_encoding("iso-8859-1")).should == 0
+  end
+
+  it "compares the indices of the encodings when the strings have identical non-ASCII-compatible bytes" do
+    xff_1 = [0xFF].pack('C').force_encoding("utf-8")
+    xff_2 = [0xFF].pack('C').force_encoding("iso-8859-1")
+    (xff_1 <=> xff_2).should == -1
+    (xff_2 <=> xff_1).should ==  1
+  end
+end
+
+# Note: This is inconsistent with Array#<=> which calls #to_ary instead of
+# just using it as an indicator.
+describe "String#<=>" do
+  it "returns nil if its argument provides neither #to_str nor #<=>" do
+    ("abc" <=> mock('x')).should be_nil
+  end
+
+  it "uses the result of calling #to_str for comparison when #to_str is defined" do
+    obj = mock('x')
+    obj.should_receive(:to_str).and_return("aaa")
+
+    ("abc" <=> obj).should == 1
+  end
+
+  it "uses the result of calling #<=> on its argument when #<=> is defined but #to_str is not" do
+    obj = mock('x')
+    obj.should_receive(:<=>).and_return(-1)
+
+    ("abc" <=> obj).should == 1
+  end
+
+  it "returns nil if argument also uses an inverse comparison for <=>" do
+    obj = mock('x')
+    def obj.<=>(other); other <=> self; end
+    obj.should_receive(:<=>).once
+
+    ("abc" <=> obj).should be_nil
+  end
+end