Api Requestor

IApiRequestor.cs

public interface IApiRequester
{
	Task<TResult> PostAsyncResult<TResult>(Uri uri, object data) where TResult : class;
	Task<TResult> GetAsyncResult<TResult>(Uri uri) where TResult : class;
}

ExampleTest.cs

public static class SearchItemsDataServiceTests
{
	[TestFixture]
	public class when_getting_data_to_build_the_search_view
	{
		[Test]
		public void then_should_get_search_data_to_build_search_view()
		{
			// Arrange
			var url = @"http://test";

			var apiRequestor = new Mock<IApiRequester>();
			var getModelTask = Task.Run(() => new Model());
			
			apiRequestor.Setup(
				requester => requester.GetAsyncResult<Model>(new Uri(url)))
				.Returns(getModelTask);
		   
			var searchItemsDataService = new SearchItemsDataService(apiRequestor.Object);

			// Act
			var searchDataModel = searchItemsDataService.GetDataForSearchView();

			// Assert
			Assert.That(searchDataModel, Is.Not.Null);
		}
	}
	
	[TestFixture]
	public class when_getting_data_to_build_the_search_result
	{
		[Test]
		public void then_should_get_search_data_to_build_search_view()
		{
			// Arrange
			var url = @"http://test/";
			
			var apiRequester = new Mock<IApiRequester>();
			var param = new Param();

			Func<Task<IList<Model>>> listOfModelFunc = () =>
				Task.Run<IList<Model>>(() => new List<Model> {new Model()});

			apiRequester.Setup(
				requester =>
					requester.PostAsyncResult<IList<Model>>(
						new Uri(url), param))
				.Returns(listOfModelFunc);

			var searchItemsDataService = new SearchItemsDataService(apiRequester.Object);

			// Act
			var searchResult = searchItemsDataService.GetSearchResult(param);

			// Assert
			Assert.That(searchResult, Is.Not.Null);
		}
	}

}

UserCredentialApiRequester.cs

public class UserCredentialApiRequester : IApiRequester
{
	private static readonly HttpClient HttpClient =
		new HttpClient(new HttpClientHandler {UseDefaultCredentials = true});
	
	public async Task<TResult> PostAsyncResult<TResult>(Uri uri, object data) where TResult : class
	{
		HttpClient.DefaultRequestHeaders.Accept.Clear();
		HttpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
		
		var asyncResult = await HttpClient.PostAsync(uri, data, new JsonMediaTypeFormatter()).ConfigureAwait(false);
		
		if (!asyncResult.IsSuccessStatusCode)
		{
			return null;
		}
		return await asyncResult.Content.ReadAsAsync<TResult>();
	}

	public async Task<TResult> GetAsyncResult<TResult>(Uri uri) where TResult : class
	{
		HttpClient.DefaultRequestHeaders.Accept.Clear();
		HttpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

		var asyncResult = await HttpClient.GetAsync(uri).ConfigureAwait(false);

		if (!asyncResult.IsSuccessStatusCode)
		{
			return null;
		}
		return await asyncResult.Content.ReadAsAsync<TResult>();
	}
}