public void IsRecipesControllerGetPhoto() { //Arrange var fileMock = new Mock <IFormFile>(); //Setup mock file using a memory stream var content = "Hello World from a Fake File"; var fileName = "PysznaHerbata.jpeg"; var ms = new MemoryStream(); var writer = new StreamWriter(ms); writer.Write(content); writer.Flush(); ms.Position = 0; fileMock.Setup(x => x.OpenReadStream()).Returns(ms); fileMock.Setup(x => x.FileName).Returns(fileName); fileMock.Setup(x => x.Length).Returns(ms.Length); fileMock.Setup(x => x.CopyToAsync(It.IsAny <Stream>(), CancellationToken.None)).Returns(Task.CompletedTask); var file = fileMock.Object; //Stworz plik na potrzeby symulacji pobrania pliku using (var fileStream = new FileStream(Directory.GetCurrentDirectory() + @"\deleteMe.jpeg", FileMode.Create)) { file.CopyTo(fileStream); } //Act var result = _recipesController.GetPhoto("herbata.jpeg"); //Assert Assert.Equal("Microsoft.AspNetCore.Mvc.FileStreamResult", result.ToString()); }