title: java.lang.IllegalMonitorStateException when testing scala future
body: <p>I have the following test class:</p>
  
  <pre><code>@RunWith(classOf[JUnitRunner])
  class NodeScalaSuite extends FunSuite with ScalaFutures {
  </code></pre>
  
  <p>Within it, I added this test to check a method returning a future:</p>
  
  <pre><code>  test("Any should return the first future") {
      val p = Promise[Int]()
      p completeWith Future.any(List(Future{wait(2000); 1}, Future{wait(1); 2}))
      whenReady(p.future) {x =&gt;
        assert(true)
      }
    }
  </code></pre>
  
  <p>(I made the assert <code>true</code> just for simpler debugging.)</p>
  
  <p>When I run the test suite I am getting this error:</p>
  
  <pre><code>[info]   The future returned an exception of type: java.lang.IllegalMonitorStateException.
  </code></pre>
  
  <p>What could cause this?</p>