[rspec-users] Assumption tests
daniel.ruby at tenner.org
Fri Oct 19 09:25:33 EDT 2007
I've been thinking about the whole validator/relationship speccing
issue, and I came up with a suggestion, which I'd love to get some
The full article is available at http://www.inter-sections.net/
2007/10/19/what-to-test-and-specify-and-where-to-do-it/ , with the
relevant bit being about halfway down, but here's the gist of it:
1. "@user.new(some attr) .. @user.should_be valid" is not behaviour
specification, it's outcome specification, and as such should not be
in any spec. It also happens to be testing someone else's code (the
rails validation code), which shouldn't need to be specified since we
didn't write it.
2. The reason why people (myself included) feel compelled to include
stuff like that is, in great part, because it helps codify our
assumptions about the way ActiveRecord (or any other external
components) work, which are sometimes not clear (as with non-trivial
validations) and liable to change as Rails evolves.
Therefore, these are a new kind of beast - not a system integration
test (not system-wide or anything to do with users), not a behaviour
specification (not specifying our own code, outcome driven) - but
instead what I'm currently calling an "assumption test".
I feel that these should be formalised, because writing somethiing like:
it “should validate_presence_of digits“ do
is only meaningful as a specification if you assume that
"validates_presence of :digits" is the right syntax to use. So
therefore, it is based on an assumption about ActiveRecord, that
should be explicitly tested for at the unit level, so that if Rails
behaves in a different way, you'll know about it at the unit level.
So my suggestion would be that we create an "assumptions" folder
somewhere in the rails folder hierarchy, so that we have 3 beasts:
assumptions, specs, and stories.
Obviously this could have dire consequences that I haven't thought
of, hence why I'd like to hear what other people's opinions are about
this. I've discussed some aspects of this briefly on #rspec with
David (chelimsky) (I'm swombat), but would love more opinions about
it, and it seems that all the fun stuff happens on the mailing list :-)
Thanks for any feedback,
(swombat on freenode#rspec)
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