Implement Complex#<=>

Implement Complex#<=> so that it is usable as an argument when
calling <=> on objects of other classes (since #coerce will coerce
such numbers to Complex).  If the complex number has a zero imaginary
part, and the other argument is a real number (or complex number with
zero imaginary part), return -1, 0, or 1.  Otherwise, return nil,
indicating the objects are not comparable.

Fixes [Bug #15857]

1 files changed, 10 insertions, 4 deletions

diff --git a/test/ruby/test_complex.rb b/test/ruby/test_complex.rb
index 3da66890c1..60a46d737d 100644
--- a/test/ruby/test_complex.rb
+++ b/test/ruby/test_complex.rb
@@ -518,9 +518,16 @@ class Complex_Test < Test::Unit::TestCase
   end
 
   def test_cmp
-    assert_raise(NoMethodError){1 <=> Complex(1,1)}
-    assert_raise(NoMethodError){Complex(1,1) <=> 1}
-    assert_raise(NoMethodError){Complex(1,1) <=> Complex(1,1)}
+    assert_nil(Complex(5, 1) <=> Complex(2))
+    assert_nil(5 <=> Complex(2, 1))
+
+    assert_equal(1, Complex(5) <=> Complex(2))
+    assert_equal(-1, Complex(2) <=> Complex(3))
+    assert_equal(0, Complex(2) <=> Complex(2))
+
+    assert_equal(1, Complex(5) <=> 2)
+    assert_equal(-1, Complex(2) <=> 3)
+    assert_equal(0, Complex(2) <=> 2)
   end
 
   def test_eqeq
@@ -891,7 +898,6 @@ class Complex_Test < Test::Unit::TestCase
   def test_respond
     c = Complex(1,1)
     assert_not_respond_to(c, :%)
-    assert_not_respond_to(c, :<=>)
     assert_not_respond_to(c, :div)
     assert_not_respond_to(c, :divmod)
     assert_not_respond_to(c, :floor)