public void GetFiles_ShouldReturnEmptyListIfNoMatch() { string[] res = null; _sut.RunWorkerAsync(); bool completed = false; _sut.RunWorkerCompleted += (sender, args) => { res = _sut.GetFiles("X"); completed = true; }; while (!completed) { Thread.CurrentThread.Join(100); } res.Length.Should().Be.EqualTo(0); }