title: Why does test report "[info] No tests were executed" for ScalaTest with a single specification in specs2?
body: <p>I wrote some very basic tests in <a href="http://specs2.org" rel="nofollow noreferrer">specs2</a>.</p>
  
  <pre><code>import org.scalatest._
  import org.specs2.mutable._
  
  class MySpec extends Specification {
      "Arithmetic" should {
          "add" in {
              "two numbers " in {
                  1 + 1 mustEqual (2)
              }
  
              "three numbers" in {
                  1 + 1 + 1 mustEqual (3)
              }
  
              "compare numbers" in {
                  2 must be lessThanOrEqualTo(1)
              }
          }
      }
  }
  </code></pre>
  
  <p>And when I run them it seems they are running as expected as you can see below</p>
  
  <p><img src="https://i.stack.imgur.com/uNNNq.png" alt="enter image description here"></p>
  
  <p>You can see that 2 tests are successful and 1 test has failed. good.</p>
  
  <p>But I don't understand why is Specs2 saying "No tests were executed" in yellow.
  What's going on?</p>