If you don’t know about FactoryGirl’s traits, here’s a quick primer:
They allow you to specify groups of attributes and callbacks that can be applied when you create the Factory in your tests. For example:
A regular factory with a sub_referral 1
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FactoryGirl . define do
factory :referral do
name 'A referral'
trait :with_sub_referrals do
after ( :create ) do | referral |
5 . times { create ( :sub_referral , referral : ref ) }
end
end
end
end
This lets you do something like
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FactoryGirl . create ( :referral , :with_sub_referrals )
But wait, I hear you say – why not just define a new factory, like so:
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FactoryGirl . define do
factory :referral do
name 'A referral'
factory :referral_with_sub_referrals do
after ( :create ) do | referral |
5 . times { create ( :sub_referral , referral : ref ) }
end
end
end
end
Sure, this works, but what if I have two traits?
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FactoryGirl . define do
factory :referral do
name 'A referral'
trait :with_sub_referrals do
after ( :create ) do | referral |
5 . times { create ( :sub_referral , referral : ref ) }
end
end
trait :with_rating do
rating 5
end
end
end
Now, this lets you do
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FactoryGirl . create ( :referral , :with_sub_referrals , :with_rating )
Now you could do this by creating multiple factories, but it ends up remarkably ugly, and there’s a tonne of code repetition (ew).
However, what if I want to specify how many sent_referrals I have in the above example. Unfortunately, you can’t pass arguments into traits. Enter ignored attributes:
An ignored attribute is exactly what it sounds like – an attribute that’s ignored when the object is created.
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FactoryGirl . define do
factory :referral do
name 'A referral'
trait :with_sub_referrals do
ignore do
sent_referrals_count 5
end
after ( :create ) do | referral , eval |
eval . sent_referral_count . times { create ( :sub_referral , referral : ref ) }
end
end
trait :with_rating do
rating 5
end
end
end
So now, to set the number of sent_referrals that are created, I can do this:
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FactoryGirl . create ( :referral , :with_sent_referrals , sent_referral_count : 3 )
Beautiful, isn’t it?
