Resizing the player window after testing has finished throws an unhandled exception

[Strilanc]

After the tests have completed successfully and the test runner has been removed from the stage so the project can run, resizing the flash player's window throws an exception:

TypeError: Error #1009: Cannot access a property or method of a null object reference.
at asunit.textui::TestRunner/resizeHandler()[as3\src\asunit\textui\TestRunner.as:84]

The code I'm using to run the tests:

    public function Main() {
        var testing:Task = AllTests.RunShowAsync(this.stage);
        testing.Await(function():void {
            if (!testing.IsFaulted()) init();
        });
    }

package UnitTests {
import asunit.framework.TestResult;
import asunit.framework.TestSuite;
import asunit.textui.TestRunner;
import Async.Task;
import Async.TaskSource;
import Async.TaskUtil;
import flash.display.Stage;
import flash.errors.IllegalOperationError;

public class AllTests extends TestSuite {
    private static var HACKY_LAST_INSTANCE:AllTests;
    public function AllTests() {
        super();

        addTest(new TestAsync());
        //... omitted ...

        HACKY_LAST_INSTANCE = this;
    }
    public static function RunShowAsync(stage : Stage) :Task {
        var r:TaskSource = new TaskSource();
        var testRunner:TestRunner = new TestRunner();
        stage.addChild(testRunner);
        var testResult:TestResult = testRunner.start(AllTests, null, TestRunner.SHOW_TRACE);
        var allTests:AllTests = HACKY_LAST_INSTANCE;

        var queryResultLooper:Function = function():void {
            if (!allTests.getIsComplete()) {
                TaskUtil.Delay(100).Await(queryResultLooper);
                return;
            }
            if (testResult.failureCount() > 0 || testResult.errorCount() > 0) {
                r.SetFault(new IllegalOperationError("Test Failures"));
            } else {
                r.SetResult(null);
                stage.removeChild(testRunner);      
            }
        }
        queryResultLooper();

        return r;
    }
}
}