title: Minitest::Spec syntax slow? (compared to ActiveSupport::TestCase)
body: <p>I've been comparing the run times of writing tests with the normal rails <code>ActiveSupport::TestCase</code> versus <code>Minitest::Spec</code></p>
  
  <p>Take the following example:</p>
  
  <pre><code>class MyDecoratorTest &lt; Minitest::Spec
    describe('#human_duration') do
      before do
        @runner = build_stubbed(:runner, { status: 'completed', duration: 121 })
        @decorator = MyDecorator.new(@booking)
      end
  
      it('is TBA when #completed? falsey') do
        @decorator.stubs({ completed?: false })
        assert_equal('TBA', @decorator.human_duration)
      end
  
      it('is properly displayed when #compelted? truthy') do
        assert_equal('121 min (2 hours and 1 min)', @decorator.human_duration)
      end
    end
  end
  </code></pre>
  
  <p>versus</p>
  
  <pre><code>class MyDecoratorTest &lt; ActiveSupport::TestCase
    setup do
      @runner = build_stubbed(:runner, { status: 'completed', duration: 121 })
      @decorator = MyDecorator.new(@booking)
    end
  
    test('is TBA when #completed? falsey') do
      @decorator.stubs({ completed?: false })
      assert_equal('TBA', @decorator.human_duration)
    end
  
    test('is properly displayed when #completed truthy') do
      assert_equal('121 min (2 hours and 1 min)', @decorator.human_duration)
    end
  end
  </code></pre>
  
  <p><code>Minitest::Spec</code> completes in ~ 0.9s</p>
  
  <p><code>ActiveSupport::TestCase</code> completes in ~ 0.4s</p>
  
  <p>The disparity is so large, I don't feel inclined to do a proper bench...but I'm wondering if/how I should go about that <em>and</em> if this is similar to other experiences on the internet???</p>