add unit/integrted tests for dpc

Yes, I’m considering to remove the exceptions here.

> On Dec 2, 2014, at 3:47 PM, Li Li <notifications@github.com> wrote:
> 
> In skxray/dpc.py:
> 
> > +
> > +    """
> > +
> > +    if bad_pixels is not None:
> > +        for x, y in bad_pixels:
> > +            try:
> > +                im[x, y] = 0
> > +            except IndexError:
> > +                raise
> > +
> > +    if roi is not None:
> > +        try:
> > +            x, y, w, l = roi
> > +        except IndexError:
> > +            raise
> > +        else:
> else should be aligned with if?
> 
> —
> Reply to this email directly or view it on GitHub <https://github.com/Nikea/scikit-xray/pull/177/files#r21189924>.
> 

--
Best Regards,

  Cheng Chang 
  Computer Engineering, Stony Brook University
  Computer Science Group, Computational Science Center, Brookhaven National Laboratory
  Tel：(001) 631-885-4922