[Python-Dev] Fwd: Change in repr of Decimal in 2.6

Sun Jul 20 04:52:21 CEST 2008

Karen Tracey wrote:
> Yeah, but the testcases are not quite that simple. They're often 
> testing return values from functions and as much verifying that the type 
> is correct as the value, so I think I'd have to change stuff like:
>> >>> f.clean('1')
> Decimal("1")
>> to:
>> >>> x = f.clean('1')
> >>> print type(x), x
> <class 'decimal.Decimal'> 1
>> right? 

 >>> f.clean('1') == Decimal('1')
True
Since 'True' is a keyword, and Guido is *very* reluctant to even add 
keywords, let alone change their spelling, I think you can depend on 
that working indefinitely. Similarly, if you now have
 >>> type(a)
<type 'int'>
you test will fail in 3.0 which instead prints '<class 'int'>. But
 >>>type(a) is int
True
will continue working.
Doctest has two quite different uses. One is to check text with 
interactive examples to make sure there are no mistakes in the examples. 
 For that, printing representations is usually the natural style. Then 
one must accept that representations change faster that object behavior.
The other use is to check code. For that, the more stilted style is 
more future-proof. For text doing double duty as a formal reference and 
code test, I would go for cross-version dependability.
Terry Jan Reedy