Minitest/GlobalExpectations cop needs method chain support

[yahonda]

Thanks for releasing rubocop-minitest 0.7.0 which implements #60.

I'd like to apply this cop to google-cloud-storage gem and found it needs method chain support.

Expected behavior

Minitest/GlobalExpectations cop corrects method chain correctly.

Actual behavior

Minitest/GlobalExpectations cop adds _() only the last method name then the test modified is getting error as follows.

% ruby method_chain.rb
Fetching gem metadata from https://rubygems.org/..................
Resolving dependencies...
Using bundler 2.1.2
Using minitest 5.14.0
Run options: --seed 39348

# Running:

E

Finished in 0.000494s, 2024.2915 runs/s, 0.0000 assertions/s.

  1) Error:
Greeting#test_0001_must say hello world in lower case:
NameError: undefined local variable or method `downcase' for #<#<Class:0x00007f880341dce0>:0x00007f88033f45e8>
    method_chain.rb:25:in `block (2 levels) in <main>'

1 runs, 0 assertions, 0 failures, 1 errors, 0 skips
%

Steps to reproduce the problem

• Create a method_chain.rb

# frozen_string_literal: true

require 'bundler/inline'

gemfile(true) do
  source 'https://rubygems.org'
  git_source(:github) { |repo| "https:/#{repo}.git" }
  gem 'minitest'
end

# Avoid `Style/Documentation: Missing top-level class documentation comment.`
class Greeting
  def say_hello
    'Hello, World!'
  end
end

require 'minitest/autorun'
describe Greeting do
  before do
    @foo = Greeting.new
  end

  it 'must say hello world in lower case' do
    @foo.say_hello.downcase.must_equal 'hello, world!'
    # Actual auto correct result
    # @foo.say_hello._(downcase).must_equal 'hello, world!'
    #
    # Expected auto correct result
    # _(@foo.say_hello.downcase).must_equal 'hello, world!'
  end
end

• Install Ruby 2.7.0 (i.e. rbenv install 2.7.0 ; rbenv global 2.7.0)
• gem install rubocop-minitest
• Run ruby method_chain.rb to see if this file shows DEPRECATED: global use of must_equal from method_chain.rb:25. Use _(obj).must_equal instead. This will fail in Minitest 6. and finishes successfully
• rubocop --require rubocop-minitest --only Minitest/GlobalExpectations method_chain.rb -a to auto-correct Minitest/GlobalExpectations cop
• Run ruby method_chain.rb

RuboCop version

% rubocop -V
0.80.0 (using Parser 2.7.0.3, running on ruby 2.7.0 x86_64-darwin19)