language/python: syntax and style cleanup

Co-authored-by: Kevin <[email protected]>
Co-authored-by: Mike McQuaid <[email protected]>

Library/Homebrew/language/python.rb

@@ -232,11 +232,11 @@ def virtualenv_install_with_resources(using: nil, system_site_packages: true, wi
  python = "python3" if python == "python"
  end
 
- venv_resources = if without.blank? && start_with.blank? && end_with.blank?
+ venv_resources = if without.nil? && start_with.nil? && end_with.nil?
  resources
  else
  remaining_resources = resources.to_h { |resource| [resource.name, resource] }
- unless (unknown_resource = Array(without).find { |r| remaining_resources.delete(r).nil? }).nil?
+ if (unknown_resource = Array(without).find { |r| remaining_resources.delete(r).nil? })
  raise ArgumentError, "#{__method__} `without` includes unknown resource \"#{unknown_resource}\""
  end
 
@@ -246,10 +246,9 @@ def virtualenv_install_with_resources(using: nil, system_site_packages: true, wi
  raise ArgumentError, "#{__method__} `start_with` includes unknown resource \"#{start_with[index]}\""
  end
 
- end_with = Array(end_with)
- end_with_resources = end_with.map { |r| remaining_resources.delete(r) }
- unless (index = end_with_resources.find_index(nil)).nil?
- raise ArgumentError, "#{__method__} `end_with` includes unknown resource \"#{end_with[index]}\""
+ end_with_resources = Array(end_with).map do |r|
+ remaining_resources.delete(r) ||
+ raise(ArgumentError, "#{__method__} `end_with` includes unknown resource \"#{r}\"")
  end
 
  start_with_resources + remaining_resources.values + end_with_resources

Library/Homebrew/test/language/python/virtualenv_spec.rb

@@ -8,7 +8,10 @@
  let(:venv) { instance_double(Language::Python::Virtualenv::Virtualenv) }
  let(:f) do
  formula "foo" do
- include Language::Python::Virtualenv # rubocop:disable RSpec/DescribedClass
+ # Couldn't find a way to get described_class to work inside formula do
+ # rubocop:disable RSpec/DescribedClass
+ include Language::Python::Virtualenv
+ # rubocop:enable RSpec/DescribedClass
 
  url "https://brew.sh/foo-1.0.tgz"