1 files changed, 109 insertions, 0 deletions
diff --git a/rubocop/cop/rspec/factory_bot/inline_association.rb b/rubocop/cop/rspec/factory_bot/inline_association.rb
new file mode 100644
index 00000000000..1c2b8b55b46
--- /dev/null
+++ b/rubocop/cop/rspec/factory_bot/inline_association.rb
@@ -0,0 +1,109 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module RSpec
+      module FactoryBot
+        # This cop encourages the use of inline associations in FactoryBot.
+        # The explicit use of `create` and `build` is discouraged.
+        #
+        # See https://github.com/thoughtbot/factory_bot/blob/master/GETTING_STARTED.md#inline-definition
+        #
+        # @example
+        #
+        # Context:
+        #
+        #   Factory.define do
+        #     factory :project, class: 'Project'
+        #       # EXAMPLE below
+        #     end
+        #   end
+        #
+        # # bad
+        # creator { create(:user) }
+        # creator { create(:user, :admin) }
+        # creator { build(:user) }
+        # creator { FactoryBot.build(:user) }
+        # creator { ::FactoryBot.build(:user) }
+        # add_attribute(:creator) { build(:user) }
+        #
+        # # good
+        # creator { association(:user) }
+        # creator { association(:user, :admin) }
+        # add_attribute(:creator) { association(:user) }
+        #
+        # # Accepted
+        # after(:build) do |instance|
+        #   instance.creator = create(:user)
+        # end
+        #
+        # initialize_with do
+        #   create(:project)
+        # end
+        #
+        # creator_id { create(:user).id }
+        #
+        class InlineAssociation < RuboCop::Cop::Cop
+          MSG = 'Prefer inline `association` over `%{type}`. ' \
+            'See https://docs.gitlab.com/ee/development/testing_guide/best_practices.html#factories'
+
+          REPLACEMENT = 'association'
+
+          def_node_matcher :create_or_build, <<~PATTERN
+            (
+              send
+              ${ nil? (const { nil? (cbase) } :FactoryBot) }
+              ${ :create :build }
+              (sym _)
+              ...
+            )
+          PATTERN
+
+          def_node_matcher :association_definition, <<~PATTERN
+            (block
+              {
+                (send nil? $_)
+                (send nil? :add_attribute (sym $_))
+              }
+              ...
+            )
+          PATTERN
+
+          def_node_matcher :chained_call?, <<~PATTERN
+            (send _ _)
+          PATTERN
+
+          SKIP_NAMES = %i[initialize_with].to_set.freeze
+
+          def on_send(node)
+            _receiver, type = create_or_build(node)
+            return unless type
+            return if chained_call?(node.parent)
+            return unless inside_assocation_definition?(node)
+
+            add_offense(node, message: format(MSG, type: type))
+          end
+
+          def autocorrect(node)
+            lambda do |corrector|
+              receiver, type = create_or_build(node)
+              receiver = "#{receiver.source}." if receiver
+              expression = "#{receiver}#{type}"
+              replacement = node.source.sub(expression, REPLACEMENT)
+              corrector.replace(node.source_range, replacement)
+            end
+          end
+
+          private
+
+          def inside_assocation_definition?(node)
+            node.each_ancestor(:block).any? do |parent|
+              name = association_definition(parent)
+              name && !SKIP_NAMES.include?(name)
+            end
+          end
+        end
+      end
+    end
+  end
+end