public void AspectRatio_Verify() { var settingWrong1 = new AspectRatio(); var setting = new AspectRatio(FFmpegRatio.Create(1, 1)); Assert.Throws <InvalidOperationException>(() => { var s = settingWrong1.GetAndValidateString(); }); Assert.DoesNotThrow(() => { var s = setting.GetAndValidateString(); }); Assert.Equal(setting.GetAndValidateString(), "-aspect 1:1"); }