test_suite_spec.rb

require 'spec_helper'
require 'active_support/core_ext/string/inflections'

RSpec.describe 'TestSuite' do
  Dir['{app,lib}/**/*.rb'].each do |filename|
    context filename do
      subject { filename }

      let(:testfile) do
        filename
          .sub('app', 'spec')
          .sub('lib', 'spec/lib')
          .sub('.rb', '_spec.rb')
      end

      it 'should have tests' do
        expect(File.exist?(testfile)).to be_truthy
        class_name = File.basename(filename, '.rb').classify
        File.open(testfile, encoding: 'utf-8') do |file|
          expect(file.read).to match(class_name)
        end
      end
    end
  end
end