public async Task blah() { var wordsArray = Faker.Random.WordsArray(3); var data = new byte[20] .Concat(wordsArray .Select(Encoding.UTF8.GetBytes) .Select(bytes1 => bytes1.Append((byte)0x0).ToArray()) .SelectMany(bytes1 => bytes1)) .ToArray(); var mockFileSystem = new MockFileSystem(); mockFileSystem.AddFile("c:\\input.pmp", new MockFileData(data)); var stringField = new StringField("Test", "c:\\input.pmp", 3, mockFileSystem); var result = await stringField.GetValues().Cast <string>().ToArray().FirstAsync(); result.Should().BeEquivalentTo(wordsArray); }