flexunit 4 fails for me

I am simply running an Assert.assertTrue call and it says it fails, here is my code:

package sampleSuite.tests
{     import org.flexunit.*;     public class TestCase1     {          [Before]           public function setUp():void           {           }           [After]           public function tearDown():void           {           }           [BeforeClass]           public static function setUpBeforeClass():void           {           }           [AfterClass]           public static function tearDownAfterClass():void           {                }          [Test]          public function testFunction():void{               Assert.assertTrue();          }     }
}

Pretty straightforward code, but it keeps giving me an error expected true but returns false. TIA.