For https://github.com/rspec/rspec-core/issues/1639

.gitignore

bin
bundle
.bundle

backtick_spec.rb

class Example
  def self.doecho
    `sudo echo 1`
  end
end

RSpec.describe "Issue 1639" do
  it '#doecho' do
    expect(Example.doecho).to include("1")
  end
end

Gemfile

# A sample Gemfile
source "https://rubygems.org"

gem 'rspec'

Gemfile.lock

GEM
  remote: https://rubygems.org/
  specs:
    diff-lcs (1.2.5)
    rspec (3.0.0)
      rspec-core (~> 3.0.0)
      rspec-expectations (~> 3.0.0)
      rspec-mocks (~> 3.0.0)
    rspec-core (3.0.2)
      rspec-support (~> 3.0.0)
    rspec-expectations (3.0.2)
      diff-lcs (>= 1.2.0, < 2.0)
      rspec-support (~> 3.0.0)
    rspec-mocks (3.0.2)
      rspec-support (~> 3.0.0)
    rspec-support (3.0.2)

PLATFORMS
  ruby

DEPENDENCIES
  rspec

output.txt

$ sudo bin/rspec backtick_spec.rb --format doc

Issue 1639
  #doecho

Finished in 0.02387 seconds (files took 0.1507 seconds to load)
1 example, 0 failures