Capturing stdout for tests in Ruby

I found this on Thinking Digitally that allows me to capture stdout and test that it is correct.

require 'stringio'

def capture_stdout
  out = StringIO.new
  $stdout = out
  yield
  return out
ensure
  $stdout = STDOUT
end

Which can be used as follows

class ATest < Test::Unit::TestCase
  def zxc(text, count)
    count.times {puts text.upcase}
  end

  def test_stdout_capture
     out = capture_stdout do
        zxc('yes', 3)
     end

     assert_equal "YES\nYES\nYES\n", out.string
  end
end

Looking good, feeling bad

What do you feel about the following line of output?

20 tests, 20 assertions, 0 failures, 0 errors

Happy, sad or nervous?

Well Ruby helpfully generates the scaffolding for tests whenever you create a new controller. They look like this:

require 'test_helper'

class HomeControllerTest < ActionController::TestCase
  # Replace this with your real tests.
  test "the truth" do
    assert true
  end
end

So I have just tested that true does really equal true, twenty times. That warm fuzzy feeling is changing into a nervous tick. I propose a new rule, tests should actually test something or delete them.