unittest - what is the best way to reuse test data?

[Mike]

On Thu, Jun 4, 2009 at 4:40 AM, Terry Reedy <tjreedy at udel.edu> wrote:

> Mike wrote:
>
>> Hello,
>>
>> I'm writing an application that needs to fetch a json file from a
>> webserver. I'm writing the tests and have a question:
>>
>> if I have the following methods:
>>
>> def test_headers(self):
>>    headers = libary.get_data(data)
>>    check header status
>>
>
> With no json experience specifically....
>
> Checking I/O is nasty since the test running correctly depends on external
> resources running correctly and not just your program.  I would separate I/O
> tests from 'process the data' checks and do the latter with canned data.  If
> the canned data built into the test is the same as that on the test server,
> then testing the fetch is an equality test.
>
> Thanks, I think I need to separate the tests.

The way JSON works is: Open a url with a request <- this returns a file like
object, the JSON libary reads the file like object and returns a list of
dictionary objects.

So first I want to make sure when I do the request I get a 200 OK response,
second I want to make sure the JSON object matches my predefined object for
it (to ensure no API changes).

I think I'll have an external test, which will do two calls (unless I can
use the result of the response check test). And if this test passes I will
then run my mock test which tests for functionality (and can be run
offline). If the first fails then its an indication that the api may have
changed and I need to change my mocks.

Is this a good testing method/ approach?
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