diff options
Diffstat (limited to 'spec/ruby/core/enumerable/sum_spec.rb')
-rw-r--r-- | spec/ruby/core/enumerable/sum_spec.rb | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/spec/ruby/core/enumerable/sum_spec.rb b/spec/ruby/core/enumerable/sum_spec.rb index c9d7017b45..2eb74db6ac 100644 --- a/spec/ruby/core/enumerable/sum_spec.rb +++ b/spec/ruby/core/enumerable/sum_spec.rb @@ -22,7 +22,29 @@ describe 'Enumerable#sum' do @enum.sum.should == 5/3r end - it 'takes a block to transform the elements' do - @enum.sum { |element| element * 2 }.should == 10/3r + context 'with a block' do + it 'transforms the elements' do + @enum.sum { |element| element * 2 }.should == 10/3r + end + + it 'does not destructure array elements' do + class << @enum + def each + yield [1,2] + yield [3] + end + end + + @enum.sum(&:last).should == 5 + end + end + + # https://bugs.ruby-lang.org/issues/12217 + # https://github.com/ruby/ruby/blob/master/doc/ChangeLog/ChangeLog-2.4.0#L6208-L6214 + it "uses Kahan's compensated summation algorithm for precise sum of float numbers" do + floats = [2.7800000000000002, 5.0, 2.5, 4.44, 3.89, 3.89, 4.44, 7.78, 5.0, 2.7800000000000002, 5.0, 2.5].to_enum + naive_sum = floats.reduce { |sum, e| sum + e } + naive_sum.should == 50.00000000000001 + floats.sum.should == 50.0 end end |