class RuboCop::Cop::RSpec::NamedSubject

end
it { should be_valid }
subject(:user) { described_class.new }
RSpec.describe Foo do
# also good
end
end
expect(user.valid?).to be(true)
it ‘is valid’ do
subject(:user) { described_class.new }
RSpec.describe Foo do
# good
end
end
expect(subject.valid?).to be(true)
it ‘is valid’ do
subject { described_class.new }
RSpec.describe User do
# bad
@example
name.
the most important object in your tests so they deserve a descriptive
`subject(:your_subject_name) { … }‘. Your test subjects should be
reference your test subject you should explicitly name it using
which allows for tests like `it { should be_valid }`. If you need to
RSpec lets you declare an “implicit subject” using `subject { … }`
Checks for explicitly referenced test subjects.

def on_block(node) 

def on_block(node)
  return unless rspec_block?(node)
  subject_usage(node) do |subject_node|
    add_offense(subject_node, location: :selector)
  end
end

def subject_usage(node, &block) 

def subject_usage(node, &block)
  unnamed_subject(node, &block)
  node.each_child_node do |child|
    subject_usage(child, &block)
  end
end