def environment(variables)
      before do
        variables.each do |key, value|
          if value.nil?
            _environment.delete(key.to_s)
          else
            _environment[key.to_s] = value.to_s
          end
        end
      end
    end
def environment(variables)
      before do
        variables.each do |key, value|
          if value.nil?
            _environment.delete(key.to_s)
          else
            _environment[key.to_s] = value.to_s
          end
        end
      end
    end
Set an environment variable for this example.

 @param variables [Hash] Key/value pairs to set.
 @example
   describe 'myapp' do
     command 'myapp show'
     environment DEBUG: true
     its(:stderr) { is_expected.to include('[debug]') }
   end