public async Task GetByRecordId_ShouldHaveContainerWithContainerDataFor() { // arrange object FMrecordIdMapper(ContainerFieldTestModel o, int id) => o.FileMakerRecordId = id; var mockHttp = new MockHttpMessageHandler(); var server = "http://localhost"; var file = "test-file"; var user = "******"; var pass = "******"; var layout = "Users"; var recordId = 26; mockHttp.When(HttpMethod.Post, $"{server}/fmi/data/v1/databases/{file}/sessions") .Respond("application/json", DataApiResponses.SuccessfulAuthentication()); var b64String = System.IO.File.ReadAllText("ResponseData\\b64-string.dat"); var bytes = Convert.FromBase64String(b64String); var b64 = new ByteArrayContent(bytes); mockHttp.When(HttpMethod.Get, $"{server}/some-data-path") .Respond(b64); mockHttp.When(HttpMethod.Get, $"{server}/fmi/data/v1/databases/{file}/layouts/{layout}/records/{recordId}") .Respond("application/json", DataApiResponses.SuccessfulGetByIdWithContainer(recordId, $"{server}/some-data-path")); var fdc = new FileMakerRestClient(mockHttp.ToHttpClient(), server, file, user, pass); // act var response = await fdc.GetByFileMakerIdAsync <ContainerFieldTestModel>(recordId, FMrecordIdMapper); // assert Assert.Equal(bytes, response.SomeContainerFieldData); }