numeric.c: round to nearest even

* numeric.c (flo_round, int_round): support round-to-nearest-even
  semantics of IEEE 754 to match sprintf behavior, and add `half:`
  optional keyword argument for the old behavior.
  [ruby-core:76273] [Bug #12548]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56590 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 13 insertions, 10 deletions

diff --git a/test/ruby/test_rational.rb b/test/ruby/test_rational.rb
index 387f4121cf..d65c292970 100644
--- a/test/ruby/test_rational.rb
+++ b/test/ruby/test_rational.rb
@@ -597,17 +597,20 @@ class Rational_Test < Test::Unit::TestCase
   end
 
   def test_trunc
-    [[Rational(13, 5),  [ 2,  3,  2,  3]], #  2.6
-     [Rational(5, 2),   [ 2,  3,  2,  3]], #  2.5
-     [Rational(12, 5),  [ 2,  3,  2,  2]], #  2.4
-     [Rational(-12,5),  [-3, -2, -2, -2]], # -2.4
-     [Rational(-5, 2),  [-3, -2, -2, -3]], # -2.5
-     [Rational(-13, 5), [-3, -2, -2, -3]], # -2.6
+    [[Rational(13, 5),  [ 2,  3,  2,  3,  3,  3]], #  2.6
+     [Rational(5, 2),   [ 2,  3,  2,  2,  2,  3]], #  2.5
+     [Rational(12, 5),  [ 2,  3,  2,  2,  2,  2]], #  2.4
+     [Rational(-12,5),  [-3, -2, -2, -2, -2, -2]], # -2.4
+     [Rational(-5, 2),  [-3, -2, -2, -2, -2, -3]], # -2.5
+     [Rational(-13, 5), [-3, -2, -2, -3, -3, -3]], # -2.6
     ].each do |i, a|
-      assert_equal(a[0], i.floor)
-      assert_equal(a[1], i.ceil)
-      assert_equal(a[2], i.truncate)
-      assert_equal(a[3], i.round)
+      s = proc {i.inspect}
+      assert_equal(a[0], i.floor, s)
+      assert_equal(a[1], i.ceil, s)
+      assert_equal(a[2], i.truncate, s)
+      assert_equal(a[3], i.round, s)
+      assert_equal(a[4], i.round(half: :even), s)
+      assert_equal(a[5], i.round(half: :up), s)
     end
   end