/
let_setup.rb
64 lines (55 loc) · 1.56 KB
/
let_setup.rb
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# frozen_string_literal: true
module RuboCop
module Cop
module RSpec
# Checks unreferenced `let!` calls being used for test setup.
#
# @example
# # Bad
# let!(:my_widget) { create(:widget) }
#
# it 'counts widgets' do
# expect(Widget.count).to eq(1)
# end
#
# # Good
# it 'counts widgets' do
# create(:widget)
# expect(Widget.count).to eq(1)
# end
#
# # Good
# before { create(:widget) }
#
# it 'counts widgets' do
# expect(Widget.count).to eq(1)
# end
class LetSetup < Cop
MSG = 'Do not use `let!` to setup objects not referenced in tests.'
def_node_matcher :let_bang, <<-PATTERN
(block $(send nil? :let! (sym $_)) args ...)
PATTERN
def_node_search :method_called?, '(send nil? %)'
def on_block(node)
return unless example_group?(node)
unused_let_bang(node) do |let|
add_offense(let)
end
end
private
def unused_let_bang(node)
child_let_bang(node) do |method_send, method_name|
yield(method_send) unless method_called?(node, method_name)
end
end
def child_let_bang(block_node)
return unless block_node.body&.begin_type?
block_node.body.each_child_node(:block) do |child|
node_with_name = let_bang(child)
yield node_with_name if node_with_name
end
end
end
end
end
end