unit test strategy

[Steven D'Aprano]

On Fri, 14 Sep 2012 19:59:29 -0700, Aaron Brady wrote:

> Hello,
> 
> I've developing a test script.  There's a lot of repetition.  I want to
> introduce a strategy for approaching it, but I don't want the program to
> be discredited because of the test script.

Test scripts should be simple enough that they don't require test scripts 
of their own. Or at least, not too many "test-the-test" tests. It is 
possible to avoid repetition without making convoluted, hard to 
understand code. Based on the tiny code fragments you give below, I 
suspect that your test script will need more testing than the code it 
tests!


> Therefore, I'd like to know
> what people's reactions to and thoughts about it are.

I'd love to make some suggestions, but I have *no idea* what you are 
talking about. See further comments below:


> The first strategy I used created an iterator and advanced it between
> each step:

What are you using an iterator for? What does this have to do with unit 
testing?

So far, your explanation is rather lacking. It's a bit like:

"I want to create an alarm system for my home, so I put in a screw and 
tightened it after each step."

Doesn't really help us understand what you are doing.


> 	self.op_chain(range(5), ('add', 5))
> 	self.op_chain(range(5), ('add', -2), ('add', -1))
> 	self.op_chain(range(5), ('discard', -1), ('add', 5))
> 	self.op_chain_ok(range(5), ('update', [0, 1]))
> Etc.

Where is the iterator you created? Where are you advancing it? What's 
op_chain do?


> I'm considering something more complicated.  'iN' creates iterator N,
> 'nN' advances iterator N, an exception calls 'assertRaises', and the
> rest are function calls.
[...]

You've proven that even in Python people can write obfuscated code.


> Do you think the 2nd version is legible?

Neither version is even close to legible.


> Could it interfere with the accuracy of the test?

Who knows? I have no clue what your code is doing, it could be doing 
*anything*.



-- 
Steven