Bug #15432
closedFloat の NaN のみを含む配列比較のテスト
Description
Float の NaN のみを含む配列比較のテストが以下にあります。
## spec/ruby/core/array/equal_value_spec.rb:47
# As per bug #1720
it "returns false for [NaN] == [NaN]" do
[nan_value].should_not == [nan_value]
end
しかし、これは #1720 で未定義動作とするとなったと思うので不要ではないでしょうか。
現状では以下のようになるので意味のないテストだと思います。
[Float::NAN] == [Float::NAN] #=> true
[Float::NAN] == [0/0.0] #=> false
Updated by jeremyevans0 (Jeremy Evans) over 5 years ago
I agree that keeping this spec does not make sense. If nobody objects within the next week, I will delete the spec.
Updated by jeremyevans (Jeremy Evans) over 5 years ago
- Status changed from Open to Closed
Applied in changeset git|a0af60c7f2d852faa6d3263874224dd7950bda43.
Remove spec testing undefined behavior
Fixes [Bug #15432]
Updated by Eregon (Benoit Daloze) over 5 years ago
It makes sense in the context of #1720.
I.e., all Ruby implementations behave that way, because Float::NAN.equal? Float::NAN
must be true, and Array#== uses an #equal? + a #== check, not just #==. I want to restore the spec and add that explanation.
IMHO there is no "undefined behavior" in Ruby, there is MRI behavior and that's what other Ruby implementations have to comply to, unless proven a bug or desirable to differ.
Updated by Eregon (Benoit Daloze) over 5 years ago
Actually, the should_not
above indeed doesn't make much sense, because it relies on nan_value
returning different NaNs, which is probably platform-specific.
I added a spec for this case: [Float::NAN].should == [Float::NAN]
.