title: ScalaTest on sbt not running any tests
body: <p>I am trying to run my tests with:
  sbt and then test.</p>
  
  <p>My build.sbt looks like this</p>
  
  <pre><code>lazy val scalatest =  "org.scalatest" % "scalatest_2.11" % "2.2.4" % "test"
  lazy val root = (project in file(".")).
  settings(
      name := "highlight2pdf",
      version := "0.1",
      scalaVersion := "2.11.6",
      libraryDependencies +=  scalatest
  )
  </code></pre>
  
  <p>And i just put the example test on test/scala </p>
  
  <pre><code>    import collection.mutable.Stack
      import org.scalatest._
  
      class ExampleSpec extends FlatSpec with Matchers {
  
          "A Stack" should "pop values in last-in-first-out order" in {
              val stack = new Stack[Int]
              stack.push(1)
              stack.push(2)
              stack.pop() should be (2)
              stack.pop() should be (1)
          }
  
          it should "throw NoSuchElementException if an empty stack is popped" in {
              val emptyStack = new Stack[Int]
              a [NoSuchElementException] should be thrownBy {
                  emptyStack.pop()
              } 
          }
      }
  </code></pre>
  
  <p>Still it always show:</p>
  
  <p>[info] No tests were executed.</p>
  
  <p>Any thoughts on why it's not working?</p>