Add a new QA::ElementWithPattern cop

This cop forbids the use of `element :foo, 'pattern'` and
`element :bar, /pattern/` in QA files.

Signed-off-by: Rémy Coutable <remy@rymai.me>

3 files changed, 51 insertions, 0 deletions

diff --git a/rubocop/cop/qa/element_with_pattern.rb b/rubocop/cop/qa/element_with_pattern.rb
new file mode 100644
index 00000000000..9d80946f1ba
--- /dev/null
+++ b/rubocop/cop/qa/element_with_pattern.rb
@@ -0,0 +1,39 @@
+require_relative '../../qa_helpers'
+
+module RuboCop
+  module Cop
+    module QA
+      # This cop checks for the usage of factories in migration specs
+      #
+      # @example
+      #
+      #   # bad
+      #   let(:user) { create(:user) }
+      #
+      #   # good
+      #   let(:users) { table(:users) }
+      #   let(:user) { users.create!(name: 'User 1', username: 'user1') }
+      class ElementWithPattern < RuboCop::Cop::Cop
+        include QAHelpers
+
+        MESSAGE = "Don't use a pattern for element, create a corresponding `%s` instead.".freeze
+
+        def on_send(node)
+          return unless in_qa_file?(node)
+          return unless method_name(node).to_s == 'element'
+
+          element_name, pattern = node.arguments
+          return unless pattern
+
+          add_offense(node, location: pattern.source_range, message: MESSAGE % "qa-#{element_name.value.to_s.tr('_', '-')}")
+        end
+
+        private
+
+        def method_name(node)
+          node.children[1]
+        end
+      end
+    end
+  end
+end
diff --git a/rubocop/qa_helpers.rb b/rubocop/qa_helpers.rb
new file mode 100644
index 00000000000..f4adf7f4e9f
--- /dev/null
+++ b/rubocop/qa_helpers.rb
@@ -0,0 +1,11 @@
+module RuboCop
+  # Module containing helper methods for writing QA cops.
+  module QAHelpers
+    # Returns true if the given node originated from the qa/ directory.
+    def in_qa_file?(node)
+      path = node.location.expression.source_buffer.name
+
+      path.start_with?(File.join(Dir.pwd, 'qa'))
+    end
+  end
+end
diff --git a/rubocop/rubocop.rb b/rubocop/rubocop.rb
index 76d6037706e..6c9b8753c1a 100644
--- a/rubocop/rubocop.rb
+++ b/rubocop/rubocop.rb
@@ -29,6 +29,7 @@ require_relative 'cop/migration/update_large_table'
 require_relative 'cop/project_path_helper'
 require_relative 'cop/rspec/env_assignment'
 require_relative 'cop/rspec/factories_in_migration_specs'
+require_relative 'cop/qa/element_with_pattern'
 require_relative 'cop/sidekiq_options_queue'
 require_relative 'cop/destroy_all'
 require_relative 'cop/ruby_interpolation_in_translation'