Spec-ing a nested object is saved on the specs of the object it is nested into

Testing RSpec
1

hi there,
I have a Rails model A, that has_one model B, model A have a method
called
save_nested_b that:

  • context ‘invalid B params’
    ** context ‘no nested B exists’ => do nothing
    ** context ‘nested B exists’ => remove it

  • context ‘valid B params’
    ** context ‘no nested B exists’ => create it
    ** context ‘nested B exists’ => remove it and create new one (or edit
    attributes linking to A)

the save_nested_b method implementation should not be problematic. My
question is:

on A specs I want to make sure all above on the list happens but not
having
to repeat all B validations on making ‘invalid B params’ examples,
because B
have its own specs, and also the A specs for save_nested_b will be
brittle
when B validations change (not to mention the combinations of invalid
fields
can be long)

how would you do this? would you do a loose thing like:

context ‘invalid B params’ do
…
a.save_nested_b nil
a.should have_no_b
…
end

giving it a more thought after writing this email I guess I would go for
this approach, what do you think?

greetings,
joaquin

2

On Fri, Mar 12, 2010 at 7:45 AM, Joaquin Rivera P.
[email protected] wrote:

attributes linking to A)
how would you do this? would you do a loose thing like:

context ‘invalid B params’ do
…
a.save_nested_b nil
a.should have_no_b
…
end

giving it a more thought after writing this email I guess I would go for this approach, what do you think?

Depends on who is calling save_nested_b. I usually save associations
via callbacks as part of the save operation, and wouldn’t call
save_nested_b from outside the A object. In that case, I’d treat
save_nested_b as a private method and likely not spec it directly.
i.e.

a = A.create!(valid_a_attributes, :b => valid_b_attributes)
a.should have_a_b

a = A.create!(valid_a_attributes, :b => invalid_b_attributes)
a.should have_no_b

etc

WDYT?

David

3

thanks for your reply David,
what worried me (well, got me thinking) was having to put on A’s specs
too
much knowledge about when B’s attributes were valid or not. I ended up
doing
more or less what you expose, but only:

  • using nil as the invalid input
  • using one valid combination for the valid ones

greetings,
joaquin

2010/3/15 David C. [email protected]