[Python-Dev] How far to go with user-friendliness

[Robert Collins]

On 15 July 2015 at 09:41, A.M. Kuchling <amk at amk.ca> wrote:
> On Tue, Jul 14, 2015 at 09:53:33AM -0700, Ethan Furman wrote:
>> Part of writing tests is making sure they fail (and for the right reason) -- proper testing of the tests would reveal such a typo.
>
> And there are other failure modes for writing tests that succeed but
> are not testing what you think.  For example, you might re-use the
> same method name:
>
>    def test_connection(self):
>        # Never executed
>        ...
>
>    ... 200 lines and 10 other test methods later ...
>
>    def test_connection(self):
>        ...
>
> Or misuse assertRaises:
>
>    with self.assertRaises(TypeError):
>        1 + "a"
>        # Second statement never reached
>        [] + 'b'
>
> I don't think unittest can protect its users from such things.

It can't, but there is a sliding scale of API usability, and we should
try to be up the good end of that :).

http://sweng.the-davies.net/Home/rustys-api-design-manifesto

-Rob

-- 
Robert Collins <rbtcollins at hp.com>
Distinguished Technologist
HP Converged Cloud