Skip to main content

A Demo In .NET6 Mock HttpClient Using XUnit

In this article, we are going to test our HttpClient instance in .NET6 application by mocking it using the XUnit.

Create An API And Unit Test Project:

Let's create a .Net6 Web API and xUnit sample applications to accomplish our demo. We can use either Visual Studio 2022 or Visual Studio Code(using .NET CLI commands) to create any.Net6 application. For this demo, I'm using the 'Visual Studio Code'(using the .NET CLI command) editor.

Create a folder where we want to set up our applications. Then add a solution file by running the below command.
Command To Add Solution File:
dotnet new sln -n Name_of_your_solution_file

Now let's create a .NET6 Web API project.
dotnet new webapi -o Name_of_your_API_project

Now let's create xUnit project.
dotnet new xunit -o Name_of_your_API_project

Now add our API and xUnit project to our solution file
dotnet sln {your_solution}.sln add {Your_API_Project_Folder}/{Your_API_ProjectName}.csproj

dotnet sln {your_solution}.sln add {Your_xUnit_Project_Folder}/{Your_xUnit_ProjectName}.csproj

Add the API project reference to the Test project.
dotnet add {Your_xUnit_Project_Folder}/{Your_xUnit_ProjectName}.csproj reference {Your_API_Project_Folder}/{Your_API_ProjectName}.csproj

xUnit Project Folder Structure:

Install Required NuGet Packages:

Now install the 'Moq' NuGet Package in the xUnit project.
.NET CLI Command
dotnet add package Moq --version 4.18.1

Package Manager
Install-Package Moq -Version 4.18.1

Now install the 'FluentAssertion' NuGet Package in the xUnit project.
.NET CLI Command
dotnet add package FluentAssertions --version 6.7.0

Package Manager
Install-Package FluentAssertions -Version 6.7.0

Test Case To Mock HttpClient:

In an API project, implemented a service to consume an external API using the HttpClient instance, let's try to write the test case for that service by mocking the HttpClient.

So let's understand the logic inside of the API project first.
Api_Project/Services/Client1Service.cs:
using Dot6.HttpMock.Api.Models;

namespace Dot6.HttpMock.Api.Services;

public class Client1Service: IClient1Service
{
    private readonly HttpClient _httpClient;
    public Client1Service(HttpClient httpClient)
    {
        _httpClient = httpClient;
    }

    public async Task<PublicApiContainer> Get()
    {
        return await _httpClient.GetFromJsonAsync<PublicApiContainer>("/entries");
    }
}
  • Here is our simple 'Client1Service' that consumes a third-party API.
  • (Line: 7-11) Injected the 'HttpClient' instance into the constructor of the 'Client1Service'.
  • (Line: 15) The 'GetFromJsonAsync()' method invokes third-party endpoint. Here is one thing we have to remember 'GetFromJsonAsync()' or any other API invoking methods internal calls the 'SendAsync' or 'Send' protected method.
Api_Project/Program.cs: 
builder.Services.AddHttpClient<IClient1Service, Client1Service>(options =>
{
    options.BaseAddress = new Uri("https://api.publicapis.org");
});
  • Here register our 'Client1Service' with the 'AddHttpClient' service that will help to inject the 'HttpClient' instance into the 'Client1Service' constructor. Also, register the base address of the third-party endpoint.
Now our target is to write a test case for the 'Get()' method in the 'Client1Service'.

Let's mock the 'HttpMessageHandler'. So let's create a file like 'HttpClientHelper.cs' in the 'Helper' folder.
xUnit_Project/Helper/HttpClientHelper.cs:
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading;
using System.Threading.Tasks;
using Moq;
using Moq.Protected;
using Newtonsoft.Json;

namespace Dot6.HttpMock.Test.Helpers;

public class HttpClientHelper
{
    public static Mock<HttpMessageHandler> GetResults<T>(T response)
    {
        var mockResponse = new HttpResponseMessage()
        {
            Content = new StringContent(JsonConvert.SerializeObject(response)),
            StatusCode = HttpStatusCode.OK
        };

        mockResponse.Content.Headers.ContentType =
        new MediaTypeHeaderValue("application/json");

        var mockHandler = new Mock<HttpMessageHandler>();

        mockHandler
        .Protected()
        .Setup<Task<HttpResponseMessage>>(
            "SendAsync",
            ItExpr.IsAny<HttpRequestMessage>(),
            ItExpr.IsAny<CancellationToken>())
        .ReturnsAsync(mockResponse);

        return mockHandler;
    }
}
  • Here 'GetResults()' method returns a mocked HttpMessageHandler with mock response data.
  • (Line: 14)The 'GetResults()' takes mocked response as generic input parameter.
  • (Line: 16-20) Initialized the 'HttpResponseMessage' with stringfied response and 200(ok) status.
  • (Line: 22&23) Defined the content type.
  • (Line: 27-33) Recall code from API_Project like 'GetFromJsonAsync()' which internally invokes the 'SenAsync' protected. Here we going to mock the 'SendAsync' method with our mocked 'HttpResponseMessage' as output. Here 'ItExpr' matches any input parameters of a protected method like 'SendAsync'.
Let's mock some response data, so let's create a file like 'PublicApiMock.cs' in the 'MockData' folder.
xUnit_Project/MockData/PublicApiMock.cs:
using System.Collections.Generic;
using Dot6.HttpMock.Api.Models;

namespace Dot6.HttpMock.Test.MockData;

public class PublicApiMock
{
    public static PublicApiContainer Get()
    {
        return new PublicApiContainer
        {
            Count = 1,
            Entries = new List<PublicApi>
            {
                new PublicApi
                {
                    API = "AdoptAPet",
                    Description = "Resource to help get pets adopted",
                    Auth = "apiKey",
                    HTTPS = true,
                    Link = "https://www.adoptapet.com/public/apis/pet_list.html",
                    Category = "Animals"
                }
            }
        };
    }
}
  • Here are some sample mock data response
We have to test our external API call logic at 'Client1Service'. So let's create the test file like 'TestClient1Service.cs' in the 'System/Services' folder.
xUnit_Project/System/Services/TestClient1Service.cs:
using System;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using Dot6.HttpMock.Api.Models;
using Dot6.HttpMock.Api.Services;
using Dot6.HttpMock.Test.Helpers;
using Dot6.HttpMock.Test.MockData;
using Moq;
using Moq.Protected;
using Xunit;

namespace Dot6.HttpMock.Test.System.Services;

public class TestClient1Service
{  
    [Fact]
    public async Task Get_ShouldReturnList()
    {
        /// Arrange
        var mockData = PublicApiMock.Get();
        var mockHandler = HttpClientHelper
        .GetResults<PublicApiContainer>(mockData);

        var mockHttpClient = new HttpClient(mockHandler.Object);
        mockHttpClient.BaseAddress = new Uri("https://api.publicapis.org");

        var client1Service = new Client1Service(mockHttpClient);

        /// Act
        var results = await client1Service.Get();

        /// Assert
        Assert.NotNull(results);

        mockHandler
        .Protected()
        .Verify(
            "SendAsync",
            Times.Exactly(1),
            ItExpr.Is<HttpRequestMessage>(
                req => req.Method == HttpMethod.Get &&
                req.RequestUri == new Uri("https://api.publicapis.org/entries")),
            ItExpr.IsAny<CancellationToken>()
        );
    }
}
  • (Line: 17) The 'Fact' attribute makes the method a testable unit.
  • (Line: 21) Fetching the mock response data of type 'PublicApiContainer'.
  • (Line: 22&23) Fetching the mock of 'HttpMessageHandler'.
  • (Line: 25) Initialized HttpClient instance bypassing our 'HttpMessageHandler' as input to it. Inside of the mocked 'HttpMessageHandler', we handled the 'SendAsync' method execution.
  • (Line: 26) The base domain of the third-party endpoint.
  • (Line: 28) Initialized the 'Client1Service' by passing the 'HttpClient' instance as input.
  • (Line: 31) Invoking our actual test method that is 'Get()' in the 'Client1Service'. Since we mocked our 'HttpClient' we are going to receive our mock data as a response.
  • (Line: 34) Checking whether response data is null or not.
  • (Line: 36-45) So on mocking the 'HttpClient', to check the test more efficient way we have to call the 'MockMessageHandler.Protected().Verify()' method, here we can check whether our 'SendAsync' method is executed or not, and also we can verify the kind of request we invoked and also we can verify the requested URL.

Test Case To Mock IHttpClientFactory:

In the API project, implemented another service to consume the external API using the IHttpClientFactory, let's try to write the test case for the service by mocking the IHttpClientFactory.

So let's understand the logic inside of the API project.
Api_project/Services/Client2Service.cs:
using Dot6.HttpMock.Api.Models;

namespace Dot6.HttpMock.Api.Services;

public class Client2Service: IClient2Service
{
    private readonly IHttpClientFactory _httpClientFactory;
    public Client2Service(IHttpClientFactory httpClientFactory)
    {
        _httpClientFactory = httpClientFactory;
    }

    public async Task<PublicApiContainer> Get()
    {
        var httpclient = _httpClientFactory.CreateClient("publicAPI");
        return await httpclient.GetFromJsonAsync<PublicApiContainer>("/entries");
    }
}
  • (Line: 7-11) Injected the 'IHttpClientFactory' into the 'Client2Service'.
  • (Line: 15) Generating the 'HttpClient' instance based on the registered name in 'Program.cs'.
Api_Project/Program.cs: 
builder.Services.AddHttpClient("publicAPI", options =>
{
    options.BaseAddress = new Uri("https://api.publicapis.org");
});
  • HttpClient registered with a name.
Now our target is to write a test case for the 'Get()' method in 'Client2Service' by mocking the IHttpClientFactory. Here most of the code we are going to use is just what we have done above steps.

So let's create a new test file for services like 'Client2Service.cs'.
xUnit_Project/System/Services/Client2Service.cs:
using System;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using Dot6.HttpMock.Api.Models;
using Dot6.HttpMock.Api.Services;
using Dot6.HttpMock.Test.Helpers;
using Dot6.HttpMock.Test.MockData;
using Moq;
using Moq.Protected;
using Xunit;

namespace Dot6.HttpMock.Test.System.Services;

public class TestClient2Service
{
    [Fact]
    public async Task Get_ShouldResult()
    {
        /// Arrange
        var mockData = PublicApiMock.Get();
        var mockHandler = HttpClientHelper
        .GetResults<PublicApiContainer>(mockData);

        var mockHttpClient = new HttpClient(mockHandler.Object);
        mockHttpClient.BaseAddress = new Uri("https://api.publicapis.org");

        var mockHttpClientFactory = new Mock<IHttpClientFactory>();
        mockHttpClientFactory.Setup(_ => _.CreateClient(It.IsAny<string>()))
        .Returns(mockHttpClient);

        var client1Service = new Client2Service(mockHttpClientFactory.Object);

        /// Act
        var results = await client1Service.Get();

        /// Assert
        Assert.NotNull(results);

        mockHandler
        .Protected()
        .Verify(
            "SendAsync",
            Times.Exactly(1),
            ItExpr.Is<HttpRequestMessage>(
                req => req.Method == HttpMethod.Get &&
                req.RequestUri == new Uri("https://api.publicapis.org/entries")),
            ItExpr.IsAny<CancellationToken>()
        );
    }
}
  • (Line: 28) Mocked the IHttpClientFactory.
  • (Line: 29&30) Here mocking the 'CreateClient' method of 'IHttpClientFactory' and also returns mocked HttpClient instance from it.

Support Me!
Buy Me A Coffee PayPal Me

Video Session:

Wrapping Up:

Hopefully, I think this article delivered some useful information on Unit Testing in Asp.NetCore Web API using xUnit. by mocking the HttpClient instance. I love to have your feedback, suggestions, and better techniques in the comment section below.

Follow Me:

Labels:

Comments

Post a Comment

Popular posts from this blog

.NET6 Web API CRUD Operation With Entity Framework Core

In this article, we are going to do a small demo on AspNetCore 6 Web API CRUD operations. What Is Web API: Web API is a framework for building HTTP services that can be accessed from any client like browser, mobile devices, desktop apps. In simple terminology API(Application Programming Interface) means an interface module that contains a programming function that can be requested via HTTP calls to save or fetch the data for their respective clients. Some of the key characteristics of API: Supports HTTP verbs like 'GET', 'POST', 'PUT', 'DELETE', etc. Supports default responses like 'XML' and 'JSON'. Also can define custom responses. Supports self-hosting or individual hosting, so that all different kinds of apps can consume it. Authentication and Authorization are easy to implement. The ideal platform to build REST full services. Create A .NET6 Web API Application: Let's create a .Net6 Web API sample application to accomplish our
6 comments
Read more

Angular 14 Reactive Forms Example

In this article, we will explore the Angular(14) reactive forms with an example. Reactive Forms: Angular reactive forms support model-driven techniques to handle the form's input values. The reactive forms state is immutable, any form filed change creates a new state for the form. Reactive forms are built around observable streams, where form inputs and values are provided as streams of input values, which can be accessed synchronously. Some key notations that involve in reactive forms are like: FormControl - each input element in the form is 'FormControl'. The 'FormControl' tracks the value and validation status of form fields. FormGroup - Track the value and validate the state of the group of 'FormControl'. FormBuilder - Angular service which can be used to create the 'FormGroup' or FormControl instance quickly. Form Array - That can hold infinite form control, this helps to create dynamic forms. Create An Angular(14) Application: Let'
3 comments
Read more

Part-1 Angular JWT Authentication Using HTTP Only Cookie[Angular V13]

In this article, we are going to implement a sample angular application authentication using HTTP only cookie that contains a JWT token. HTTP Only JWT Cookie: In a SPA(Single Page Application) Authentication JWT token either can be stored in browser 'LocalStorage' or in 'Cookie'. Storing JWT token inside of the cookie then the cookie should be HTTP Only. The HTTP-Only cookie nature is that it will be only accessible by the server application. Client apps like javascript-based apps can't access the HTTP-Only cookie. So if we use authentication with HTTP only JWT cookie then we no need to implement custom logic like adding authorization header or storing token data, etc at our client application. Because once the user authenticated cookie will be automatically sent to the server by the browser on every API call. Authentication API: To implement JWT cookie authentication we need to set up an API. For that, I had created a mock authentication API(Using the NestJS Se
Post a Comment
Read more

Unit Testing Asp.NetCore Web API Using xUnit[.NET6]

In this article, we are going to write test cases to an Asp.NetCore Web API(.NET6) application using the xUnit. xUnit For .NET: The xUnit for .Net is a free, open-source, community-focused unit testing tool for .NET applications. By default .Net also provides a xUnit project template to implement test cases. Unit test cases build upon the 'AAA' formula that means 'Arrange', 'Act' and 'Assert' Arrange - Declaring variables, objects, instantiating mocks, etc. Act - Calling or invoking the method that needs to be tested. Assert - The assert ensures that code behaves as expected means yielding expected output. Create An API And Unit Test Projects: Let's create a .Net6 Web API and xUnit sample applications to accomplish our demo. We can use either Visual Studio 2022 or Visual Studio Code(using .NET CLI commands) to create any.Net6 application. For this demo, I'm using the 'Visual Studio Code'(using the .NET CLI command) editor. Create a fo
6 comments
Read more

A Small Guide On NestJS Queues

NestJS Application Queues helps to deal with application scaling and performance challenges. When To Use Queues?: API request that mostly involves in time taking operations like CPU bound operation, doing them synchronously which will result in thread blocking. So to avoid these issues, it is an appropriate way to make the CPU-bound operation separate background job.  In nestjs one of the best solutions for these kinds of tasks is to implement the Queues. For queueing mechanism in the nestjs application most recommended library is '@nestjs/bull'(Bull is nodejs queue library). The 'Bull' depends on Redis cache for data storage like a job. So in this queueing technique, we will create services like 'Producer' and 'Consumer'. The 'Producer' is used to push our jobs into the Redis stores. The consumer will read those jobs(eg: CPU Bound Operations) and process them. So by using this queues technique user requests processed very fastly because actually
7 comments
Read more

Angular 14 State Management CRUD Example With NgRx(14)

In this article, we are going to implement the Angular(14) state management CRUD example with NgRx(14) NgRx Store For State Management: In an angular application to share consistent data between multiple components, we use NgRx state management. Using NgRx state helps to avoid unwanted API calls, easy to maintain consistent data, etc. The main building blocks for the NgRx store are: Actions - NgRx actions represents event to trigger the reducers to save the data into the stores. Reducer - Reducer's pure function, which is used to create a new state on data change. Store - The store is the model or entity that holds the data. Selector - Selector to fetch the slices of data from the store to angular components. Effects - Effects deals with external network calls like API. The effect gets executed based the action performed Ngrx State Management flow: The angular component needs data for binding.  So angular component calls an action that is responsible for invoking the API call.  Aft
7 comments
Read more

Usage Of CancellationToken In Asp.Net Core Applications

When To Use CancellationToken?: In a web application request abortion or orphan, requests are quite common. On users disconnected by network interruption or navigating between multiple pages before proper response or closing of the browser, tabs make the request aborted or orphan. An orphan request can't deliver a response to the client, but it will execute all steps(like database calls, HTTP calls, etc) at the server. Complete execution of an orphan request at the server might not be a problem generally if at all requests need to work on time taking a job at the server in those cases might be nice to terminate the execution immediately. So CancellationToken can be used to terminate a request execution at the server immediately once the request is aborted or orphan. Here we are going to see some sample code snippets about implementing a CancellationToken for Entity FrameworkCore, Dapper ORM, and HttpClient calls in Asp.NetCore MVC application. Note: The sample codes I will show in
2 comments
Read more

Blazor WebAssembly Custom Authentication From Scratch

In this article, we are going to explore and implement custom authentication from the scratch. In this sample, we will use JWT authentication for user authentication. Main Building Blocks Of Blazor WebAssembly Authentication: The core concepts of blazor webassembly authentication are: AuthenticationStateProvider Service AuthorizeView Component Task<AuthenticationState> Cascading Property CascadingAuthenticationState Component AuthorizeRouteView Component AuthenticationStateProvider Service - this provider holds the authentication information about the login user. The 'GetAuthenticationStateAsync()' method in the Authentication state provider returns user AuthenticationState. The 'NotifyAuthenticationStateChaged()' to notify the latest user information within the components which using this AuthenticationStateProvider. AuthorizeView Component - displays different content depending on the user authorization state. This component uses the AuthenticationStateProvider
6 comments
Read more

How Response Caching Works In Asp.Net Core

What Is Response Caching?: Response Caching means storing of response output and using stored response until it's under it's the expiration time. Response Caching approach cuts down some requests to the server and also reduces some workload on the server. Response Caching Headers: Response Caching carried out by the few Http based headers information between client and server. Main Response Caching Headers are like below Cache-Control Pragma Vary Cache-Control Header: Cache-Control header is the main header type for the response caching. Cache-Control will be decorated with the following directives. public - this directive indicates any cache may store the response. private - this directive allows to store response with respect to a single user and can't be stored with shared cache stores. max-age - this directive represents a time to hold a response in the cache. no-cache - this directive represents no storing of response and always fetch the fr
Post a Comment
Read more

Angular 14 Crud Example

In this article, we will implement CRUD operation in the Angular 14 application. Angular: Angular is a framework that can be used to build a single-page application. Angular applications are built with components that make our code simple and clean. Angular components compose of 3 files like TypeScript File(*.ts), Html File(*.html), CSS File(*.cs) Components typescript file and HTML file support 2-way binding which means data flow is bi-directional Component typescript file listens for all HTML events from the HTML file. Create Angular(14) Application: Let's create an Angular(14) application to begin our sample. Make sure to install the Angular CLI tool into our local machine because it provides easy CLI commands to play with the angular application. Command To Install Angular CLI npm install -g @angular/cli Run the below command to create the angular application. Command To Create Angular Application ng new name_of_your_app Note: While creating the app, you will see a noti
4 comments
Read more