Fix `Rational#<=>(Numeric)`

Reported by Sergey Ukrainskiy: https://github.com/mruby/mruby/commit/f5fb1307b017fb972c12b4ec4b1866d789b0ca09#r33590698

mrbgems/mruby-rational/mrblib/rational.rb

@@ -58,11 +58,12 @@ class Rational < Numeric
     when Float
       return to_f <=> rhs
     end
+
     case rhs
     when Rational
       (numerator * rhs.denominator - denominator * rhs.numerator) <=> 0
     when Numeric
-      return rhs <=> self
+      (rhs <=> self)&.-@
     else
       nil
     end

mrbgems/mruby-rational/test/rational.rb

@@ -3,13 +3,21 @@ def assert_rational(real, exp)
   assert_float real.denominator, exp.denominator
 end
 
-def assert_equal_rational(exp, r1, r2)
+def assert_equal_rational(exp, o1, o2)
   if exp
-    assert_operator(r1, :==, r2)
-    assert_not_operator(r1, :!=, r2)
+    assert_operator(o1, :==, o2)
+    assert_not_operator(o1, :!=, o2)
   else
-    assert_not_operator(r1, :==, r2)
-    assert_operator(r1, :!=, r2)
+    assert_not_operator(o1, :==, o2)
+    assert_operator(o1, :!=, o2)
+  end
+end
+
+def assert_cmp(exp, o1, o2)
+  if exp == (o1 <=> o2)
+    pass
+  else
+    flunk "", "    Expected #{o1.inspect} <=> #{o2.inspect} to be #{exp}"
   end
 end
 
@@ -101,6 +109,156 @@ assert 'Float#==(Rational), Float#!=(Rational)' do
   assert_equal_rational(false, 3.3, Rational(13,4))
 end
 
+assert 'Rational#<=>' do
+  num = Class.new(Numeric) do
+    def initialize(n)
+      @n = n
+    end
+
+    def <=>(rhs)
+      rhs = rhs.to_i
+      rhs < 0 ? nil : @n <=> rhs
+    end
+
+    def inspect
+      "num(#{@n})"
+    end
+  end
+
+  assert_cmp(-1, Rational(-1), Rational(0))
+  assert_cmp(0, Rational(0), Rational(0))
+  assert_cmp(1, Rational(1), Rational(0))
+  assert_cmp(-1, Rational(-1), 0)
+  assert_cmp(0, Rational(0), 0)
+  assert_cmp(1, Rational(1), 0)
+  assert_cmp(-1, Rational(-1), 0.0)
+  assert_cmp(0, Rational(0), 0.0)
+  assert_cmp(1, Rational(1), 0.0)
+  assert_cmp(-1, Rational(1,2), Rational(2,3))
+  assert_cmp(0, Rational(2,3), Rational(2,3))
+  assert_cmp(1, Rational(2,3), Rational(1,2))
+  assert_cmp(1, Rational(2,3), Rational(1,2))
+  assert_cmp(1, Rational(0), Rational(-1))
+  assert_cmp(-1, Rational(0), Rational(1))
+  assert_cmp(1, Rational(2,3), Rational(1,2))
+  assert_cmp(0, Rational(2,3), Rational(2,3))
+  assert_cmp(-1, Rational(1,2), Rational(2,3))
+  assert_cmp(-1, Rational(1,2), Rational(2,3))
+  assert_cmp(nil, 3r, "3")
+  assert_cmp(1, 3r, num.new(2))
+  assert_cmp(0, 3r, num.new(3))
+  assert_cmp(-1, 3r, num.new(4))
+  assert_cmp(nil, Rational(-3), num.new(5))
+end
+
+assert 'Fixnum#<=>(Rational)' do
+  assert_cmp(-1, -2, Rational(-9,5))
+  assert_cmp(0, 5, 5r)
+  assert_cmp(1, 3, Rational(8,3))
+end
+
+assert 'Float#<=>(Rational)' do
+  assert_cmp(-1, -2.1, Rational(-9,5))
+  assert_cmp(0, 5.0, 5r)
+  assert_cmp(1, 2.7, Rational(8,3))
+end
+
+assert 'Rational#<' do
+  assert_operator(Rational(1,2), :<, Rational(2,3))
+  assert_not_operator(Rational(2,3), :<, Rational(2,3))
+  assert_operator(Rational(2,3), :<, 1)
+  assert_not_operator(2r, :<, 2)
+  assert_not_operator(Rational(2,3), :<, -3)
+  assert_operator(Rational(-4,3), :<, -0.3)
+  assert_not_operator(Rational(13,4), :<, 3.25)
+  assert_not_operator(Rational(2,3), :<, 0.6)
+  assert_raise(ArgumentError) { 1r < "2" }
+end
+
+assert 'Fixnum#<(Rational)' do
+  assert_not_operator(1, :<, Rational(2,3))
+  assert_not_operator(2, :<, 2r)
+  assert_operator(-3, :<, Rational(2,3))
+end
+
+assert 'Float#<(Rational)' do
+  assert_not_operator(-0.3, :<, Rational(-4,3))
+  assert_not_operator(3.25, :<, Rational(13,4))
+  assert_operator(0.6, :<, Rational(2,3))
+end
+
+assert 'Rational#<=' do
+  assert_operator(Rational(1,2), :<=, Rational(2,3))
+  assert_operator(Rational(2,3), :<=, Rational(2,3))
+  assert_operator(Rational(2,3), :<=, 1)
+  assert_operator(2r, :<=, 2)
+  assert_not_operator(Rational(2,3), :<=, -3)
+  assert_operator(Rational(-4,3), :<=, -0.3)
+  assert_operator(Rational(13,4), :<=, 3.25)
+  assert_not_operator(Rational(2,3), :<=, 0.6)
+  assert_raise(ArgumentError) { 1r <= "2" }
+end
+
+assert 'Fixnum#<=(Rational)' do
+  assert_not_operator(1, :<=, Rational(2,3))
+  assert_operator(2, :<=, 2r)
+  assert_operator(-3, :<=, Rational(2,3))
+end
+
+assert 'Float#<=(Rational)' do
+  assert_not_operator(-0.3, :<=, Rational(-4,3))
+  assert_operator(3.25, :<=, Rational(13,4))
+  assert_operator(0.6, :<=, Rational(2,3))
+end
+
+assert 'Rational#>' do
+  assert_not_operator(Rational(1,2), :>, Rational(2,3))
+  assert_not_operator(Rational(2,3), :>, Rational(2,3))
+  assert_not_operator(Rational(2,3), :>, 1)
+  assert_not_operator(2r, :>, 2)
+  assert_operator(Rational(2,3), :>, -3)
+  assert_not_operator(Rational(-4,3), :>, -0.3)
+  assert_not_operator(Rational(13,4), :>, 3.25)
+  assert_operator(Rational(2,3), :>, 0.6)
+  assert_raise(ArgumentError) { 1r > "2" }
+end
+
+assert 'Fixnum#>(Rational)' do
+  assert_operator(1, :>, Rational(2,3))
+  assert_not_operator(2, :>, 2r)
+  assert_not_operator(-3, :>, Rational(2,3))
+end
+
+assert 'Float#>(Rational)' do
+  assert_operator(-0.3, :>, Rational(-4,3))
+  assert_not_operator(3.25, :>, Rational(13,4))
+  assert_not_operator(0.6, :>, Rational(2,3))
+end
+
+assert 'Rational#>=' do
+  assert_not_operator(Rational(1,2), :>=, Rational(2,3))
+  assert_operator(Rational(2,3), :>=, Rational(2,3))
+  assert_not_operator(Rational(2,3), :>=, 1)
+  assert_operator(2r, :>=, 2)
+  assert_operator(Rational(2,3), :>=, -3)
+  assert_not_operator(Rational(-4,3), :>=, -0.3)
+  assert_operator(Rational(13,4), :>=, 3.25)
+  assert_operator(Rational(2,3), :>=, 0.6)
+  assert_raise(ArgumentError) { 1r >= "2" }
+end
+
+assert 'Fixnum#>=(Rational)' do
+  assert_operator(1, :>=, Rational(2,3))
+  assert_operator(2, :>=, 2r)
+  assert_not_operator(-3, :>=, Rational(2,3))
+end
+
+assert 'Float#>=(Rational)' do
+  assert_operator(-0.3, :>=, Rational(-4,3))
+  assert_operator(3.25, :>=, Rational(13,4))
+  assert_not_operator(0.6, :>=, Rational(2,3))
+end
+
 assert 'Rational#negative?' do
   assert_predicate(Rational(-2,3), :negative?)
   assert_predicate(Rational(2,-3), :negative?)