Just some examples of me using factory_bot wrong

implicit_override.rb

# Traits can be used as implicit factory attributes but if a value is set in a
# a factory, a trait cannot override that value. If you explicitely pass the trait,
# it overrides as expected.

require 'factory_bot'

FactoryBot.define do
  factory :foobot do
    foo { "parent" }
    override

    trait :override do
      foo { "not actually an override" }
    end
  end
end

puts FactoryBot.build(:foobot).foo # expected "not actually an override", got "parent"
puts FactoryBot.build(:foobot, :override).foo # "not actually an override", as expected

# But if no value is set in the parent things work as expected

FactoryBot.define do
  factory :foobot2, class: "Foobot" do
    # foo { "parent" }
    override

    trait :override do
      foo { "technically not an override bc no default value" }
    end
  end
end

puts FactoryBot.build(:foobot2).foo # technically not an override bc no default value
puts FactoryBot.build(:foobot2, :override).foo # technically not an override bc no default value

implicit_transient.rb

# Implicit traits in factories cannot override transient attributes default values

require 'factory_bot'

class Foobot
  attr_accessor :foo
end

FactoryBot.define do
  factory :foobot do
    asdfify

    trait :asdfify do
      asdf { false }
    end

    factory :asdfify2 do
      asdf { false }
    end

    transient do
      asdf { true }
    end

    after(:build) do |foo, evaluator|
      puts evaluator.asdf
    end
  end
end

puts FactoryBot.build(:foobot) # true, like the default (implicit trait ignored)
puts FactoryBot.build(:foobot, :asdfify) # false, like the trait override
puts FactoryBot.build(:asdfify2) # false, like the factory override