Add Find Or Create A Record With FactoryBot as a Rails til

Author: jbranchaud

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
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-_1138 TILs and counting..._
+_1139 TILs and counting..._
 
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@@ -692,6 +692,7 @@ _1138 TILs and counting..._
 - [Different Ways To Add A Foreign Key Reference](rails/different-ways-to-add-a-foreign-key-reference.md)
 - [Disambiguate Where In A Joined Relation](rails/disambiguate-where-in-a-joined-relation.md)
 - [Ensure Migrations Use The Latest Schema](rails/ensure-migrations-use-the-latest-schema.md)
+- [Find Or Create A Record With FactoryBot](rails/find-or-create-a-record-with-factory-bot.md)
 - [Force All Users To Sign Out](rails/force-all-users-to-sign-out.md)
 - [Generating And Executing SQL](rails/generating-and-executing-sql.md)
 - [Get An Array Of Values From The Database](rails/get-an-array-of-values-from-the-database.md)

rails/find-or-create-a-record-with-factory-bot.md

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+# Find Or Create A Record With FactoryBot
+
+I have a bunch of tests throughout my test suite that rely on a particular kind
+of unique record. Let's say it is a special admin user.
+
+```ruby
+admin = FactoryBot.create(:user, email: 'admin@company.com')
+```
+
+If this user has already been created then trying to re-create it with
+[FactoryBot](https://github.com/thoughtbot/factory_bot) will result in a unique
+email validation error.
+
+Another way to approach this would be to either find or create the admin user.
+In some standard Rails code that might look like this:
+
+```ruby
+admin =
+  User.find_by(email: 'admin@company.com') ||
+  FactoryBot.create(:user, email: 'admin@company.com')
+```
+
+There is some repetitiveness to this that I'd like to avoid. FactoryBot doesn't
+have an equivalent to ActiveRecord's `find_and_create_by`, but we can work
+around this.
+
+We can add an `initialize_with` directive to the `User` factory.
+
+```ruby
+FactoryBot.define do
+  factory :user do
+    sequence(:email) { |n| 'user#{n}@example.com' }
+
+    # a bunch of other attributes
+
+    initialize_with { User.find_or_create_by(email: email) }
+  end
+end
+```
+
+With this in place, we can call `FactoryBot.create` with the already existing
+_admin_ user and it will look up the record instead of raising a validation
+error.
+
+[source](https://stackoverflow.com/a/11799674/535590)