From: Eric Hodel <drbrain@...7.net>
Date: 2006-01-12T14:17:03+09:00
Subject: Re: unit tests and string comparisons

On Jan 11, 2006, at 5:14 PM, Joe Van Dyk wrote:

> On 1/12/06, ara.t.howard@noaa.gov <ara.t.howard@noaa.gov> wrote:
>> On Thu, 12 Jan 2006, Joe Van Dyk wrote:
>>
>>> Hi,
>>>
>>> I'm testing the equality of two rather large strings.  They look the
>>> same to me, but doing
>>>
>>> assert_equal "big ass long string", "big ass long string"
>>>
>>> says that they're different.  And they look very similar to me.  I
>>> know that they're different though, as doing "big ass long  
>>> string".sum
>>> gives a different checksum than the other one.
>>>
>>> Any ideas on how I can easily view the differences between two  
>>> long strings?
>>
>> stupid - but works:
>>
>>    harp:~ > cat a.rb
>>    a = "foobar"
>>    b = "foobaz"
>>
>>    def sdiff a, b
>>      a = a.split //
>>      b = b.split //
>>      a.zip(b).each_with_index{|cc,idx| printf "%d: %s\n", idx,  
>> cc.inspect unless cc.uniq.size == 1}
>>    end
>>
>>    sdiff a, b
>>
>>
>>    harp:~ > ruby a.rb
>>    5: ["r", "z"]
>>
>> or just dump them to two files using 'od -c' and then use 'diff -u'.
>
> Thanks, I ended up doing something similar.  I thought I recalled
> reading a post here (or maybe on the Rails mailing list) about some
> guy who was comparing large hashes and was having difficulties seeing
> the differences between the two in the unit test output.  This is sort
> of a related problem, I guess.

uh, unit_diff, from ZenTest.

http://rubyforge.org/frs/?group_id=419&release_id=3133

No, really.

-- 
Eric Hodel - drbrain@segment7.net - http://segment7.net
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