[Numpy-discussion] Test fails for rev. 2473

[Albert Strasheim]

Hello Tim

> -----Original Message-----
> From: Tim Hochberg [mailto:tim.hochberg at cox.net]
> Sent: 03 May 2006 18:21
> To: Albert Strasheim
> Cc: numpy-discussion at lists.sourceforge.net
> Subject: Re: [Numpy-discussion] Test fails for rev. 2473
> 
> Albert Strasheim wrote:

<snip>

> >I prepared two patches to turn the existing doctests into "normal" tests:
> >
> >http://projects.scipy.org/scipy/numpy/ticket/87
> >http://projects.scipy.org/scipy/numpy/ticket/88
> >
> >
> >
> In general, I'm not a big fan of turning doctests into "normal" tests.
> Any time you muck with a working test you have to worry about
> introducing bugs into the test suite. In addition doctests are
> frequently, although certainly not always. clearer than their unit test
> counterparts. It seems that the time would be better spent fixing trace
> to do the right thing in the presence of doctests. Then again, you've
> already spent the time so it's to late to unspend it I suppose.

I agree with you -- rewriting tests is suboptimal. However, in the presence
of not-perfect-yet tools I prefer to adapt my way of working so that I can
still use the tool instead of hoping that the tool will get fixed at some
undefined time in the future.

Anyway, as I noted in ticket #87, the last doctest in test_ufunclike might
be hiding a bug or there might be floating point math issues I'm unaware of.
When I run my "normal" tests for log2, I get:

Traceback (most recent call last):
  File "numpybug3.py", line 7, in ?
    assert_array_equal(b, array([2.169925, 1.20163386, 2.70043972]))
  File "C:\Python24\Lib\site-packages\numpy\testing\utils.py", line 204, in
assert_array_equal
    assert cond,\
AssertionError:
Arrays are not equal (mismatch 100.0%):
        Array 1: [ 2.1699250014423126  1.2016338611696504
2.7004397181410922]
        Array 2: [ 2.1699250000000001  1.2016338600000001
2.7004397199999999]

Is this the expected behaviour?

Regards,

Albert