public void GetTargetPath() { // Give var operatingSystemLayer = Substitute.For <IOperatingSystemLayer>(); var configService = Substitute.For <IConfigService>(); var fileRipper = new FileRipper(operatingSystemLayer, configService); // When fileRipper.TargetPathValueOf("fileName"); // Then operatingSystemLayer.Received(1).PathNameValueOf(Arg.Any <string>()); operatingSystemLayer.Received(1).PathSep(); operatingSystemLayer.Received(1).SanitizePath(Arg.Any <string>()); }