On Feb 13, 2009, at 10:52 AM, Nick Hoffman wrote:
On 12/02/2009, at 2:59 PM, David Chelimsky wrote:
On Feb 12, 2009, at 1:03 PM, Nick Hoffman <n...@deadorange.com>
wrote:
Does RSpec automatically call #valid? on ActiveRecord models?
For instance, when this example is run:
it 'should reject a nil value' do
@form = TimeShiftForm.new :file => nil
puts "@form.errors.count = <<#...@form.errors.count}>>"
@form.should have(1).error_on :file
This matcher, have(1).error_on, does call #valid.
puts "@form.errors.count = <<#...@form.errors.count}>>"
end
This is printed:
@form.errors.count = <<0>>
@form.errors.count = <<1>>
However, I never called @form.valid? , which leads me to believe
that RSpec called it for me.
In this case, yes, because the matcher needs that.
If RSpec does in fact call #valid? automatically, should we
refrain from manually calling #valid?
The fact that you are asking this shows that we're violating the
principle of least surprise. We could make it so it doesn't
validate, but that would pit the onus on users to validate
explicitly (not to mention the upgrade burden).
Thoughts?
David
I think it comes down to how much work you expect to have to do
yourself, versus how much "magic" you expect will, or would like to,
happen in the background.
It never crossed my mind that a matcher would call #valid? . My
impression of matchers was that they simply reported on whether or
not an object had a specific setting/property. I figured the matcher
simply checked the AR model object for the specified error,
regardless of whether or not I'd called #valid? .
Personally, I don't think that matchers should be modifying the
objects that they check. In my mind, a matcher is like an overseer:
it reads and reports, but doesn't tinker.
Another reason that I think matchers shouldn't call #valid? is
because of the inconsistencies doing so can produce between spec
examples. Examples that use have(X).errors_on won't have an explicit
call to #valid? , while examples that don't use that matcher, but
need #valid? to be called, will have an explicit called to #valid? .
That's my perspective on the matter. However, I'm not necessarily
advocating that the current behaviour change. Others have said that
they find it logical that #valid? is called for them. Who's to say
who's right?
I must say that I found it a bit surprising when I started using rspec
with rails (back in 0.8 or something like that).
It's something I figured out after a bit of head scratching, but I
think it's something my specs are better for in the long run. If it
didn't call valid?, I'd probably end up defining a helper method for
my specs that wrapped that behavior.
Scott
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