public void IsPng_PngFile_ReturnsTrue() { using (var stream = File.OpenRead($"{ImageSourcePath}\\image.png")) { var formFile = new FormFile(stream, 0, stream.Length, null, Path.GetFileName(stream.Name)) { Headers = new HeaderDictionary(), ContentType = "image/png" }; var result = formFile.IsPNG(); Assert.IsTrue(result); } }