does lack of type declarations make Python unsafe?

David Bolen db3l at
Wed Jun 18 00:31:25 CEST 2003

Moshe Zadka <m at> writes:

> It's better to teach people the truth, no? Instead of teaching them
> about some rosy place which doesn't exist. I feel you are doing
> unit-testing a disservice: if someone buys into it, and finds that
> it isn't a win always, he'll just assume that it is worth nothing.
> In fact, I assumed tests are worth nothing after finding some glaring
> holes in XP's logic, and it took me a long time to be convinced that
> they are ever helpful. Assuming there are others like me, it is better
> to be honest about the limitations of technology first :)

One thing that made a big difference for me when I was doing my own
investigation of XP practices was the point when I realized that
equating TDD with unit testing was a disservice (probably to both
concepts), at least to my own conceptual model of things.

There have been several threads on the XP lists (at Yahoo I think)
with respect to TDD being test-driven-development, or even more
properly, test-driven-design.  That it is also close to traditional
unit tests, and that it often gives you reasonable coverage testing,
is a secondary effect.  It's primary effect is that you are using the
tests as an act of "design," and through the growing base of tests
letting your design evolve and emerge.  It doesn't preclude other
manners of testing (or not doing them at all) and of course XP even
has an extra level in the assurance tests.

At least for me, seeing TDD really as a "design" methodology and not
just unit testing (which I can easily see being done both before and
after the fact) was a significant change.  YMMV.

-- David

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