Issue #6100 has been reported by Heesob Park.

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Bug #6100: Unexpected value of Time#iso8601 with floating point argument.
https://bugs.ruby-lang.org/issues/6100

Author: Heesob Park
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 
ruby -v: ruby 2.0.0dev (2012-02-21 trunk 34712) [i386-mswin32_100]


I found Time#iso8601 returns unexpected value in case of floating point argument.

C:\>irb
irb(main):001:0> require 'time'
=> true
irb(main):002:0> a = Time.now
=> 2012-02-28 16:12:18 +0900
irb(main):003:0> a.iso8601(10)
=> "2012-02-28T16:12:18.3203750000+09:00"
irb(main):004:0> a.iso8601(1)
=> "2012-02-28T16:12:18.3+09:00"
irb(main):005:0> a.iso8601(1.5)
=> "2012-02-28T16:12:18.10+09:00"
irb(main):006:0> a.iso8601(1.6)
=> "2012-02-28T16:12:18.12+09:00"
irb(main):007:0> a.iso8601(1.7)
=> "2012-02-28T16:12:18.16+09:00"
irb(main):008:0> a.iso8601(1.8)
=> "2012-02-28T16:12:18.20+09:00"
irb(main):009:0> a.iso8601(2)
=> "2012-02-28T16:12:18.32+09:00"
irb(main):010:0> a.iso8601(2.1)
=> "2012-02-28T16:12:18.40+09:00"

By the way, In ruby 1.8.7, it works as expected.

$ irb
irb(main):001:0> require 'time'
=> true
irb(main):002:0> a = Time.now
=> Tue Feb 28 16:14:07 +0900 2012
irb(main):003:0> a.iso8601(10)
=> "2012-02-28T16:14:07.3405450000+09:00"
irb(main):004:0> a.iso8601(1)
=> "2012-02-28T16:14:07.3+09:00"
irb(main):005:0> a.iso8601(1.1)
=> "2012-02-28T16:14:07.3+09:00"
irb(main):006:0> a.iso8601(1.5)
=> "2012-02-28T16:14:07.3+09:00"
irb(main):007:0> a.iso8601(1.9)
=> "2012-02-28T16:14:07.3+09:00"
irb(main):008:0> a.iso8601(2)
=> "2012-02-28T16:14:07.34+09:00"
irb(main):010:0> a.iso8601(2.1)
=> "2012-02-28T16:14:07.34+09:00"




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