Hello World Tutorial

This documentation will help you go from a total beginner to a seasoned NBomber expert!

Follow along to learn how to:

• Create and Run a test.
• Create HTTP load test.
• Ramp the number of requests up and down as the test runs.

info

Installation prerequisites

• .NET SDK.
• Visual Studio Code with C# extension installed.

Create console application project

dotnet new console -n [project_name] -lang ["C#"]

dotnet new console -n MyLoadTest -lang "C#"
cd MyLoadTest

Add NBomber package

dotnet add package NBomber

Create hello world load test

Let's first start with an empty hello world example to get more familiar with NBomber. In this example, we will define one simple Step and Scenario which does nothing.

Program.cs

using System;
using System.Threading.Tasks;
using NBomber.CSharp;

namespace MyLoadTest
{
    class Program
    {
        static void Main(string[] args)
        {   
            var scenario = Scenario.Create("hello_world_scenario", async context =>
            {
                // you can define and execute any logic here,
                // for example: send http request, SQL query etc
                // NBomber will measure how much time it takes to execute your logic
                await Task.Delay(1_000);

                return Response.Ok();
            })
            .WithoutWarmUp()
            .WithLoadSimulations(
                Simulation.Inject(rate: 10,
                                  interval: TimeSpan.FromSeconds(1),
                                  during: TimeSpan.FromSeconds(30))
            );

            NBomberRunner
                .RegisterScenarios(scenario)
                .Run();
        }
    }
}

Run load test

dotnet run -c Release

After running a test you will get a report. Don't get scared, we can skip it for now. Later we will understand how to analyse such reports.

Create simple HTTP load test (not production-ready)

Now, let's add HTTP client to test a web server and then run it.

Program.cs

using System;
using System.Threading.Tasks;
using System.Net.Http;
using NBomber.CSharp;

namespace MyLoadTest
{
    class Program
    {
        static void Main(string[] args)
        {   
            using var httpClient = new HttpClient();

            var scenario = Scenario.Create("hello_world_scenario", async context =>
            {
                var response = await httpClient.GetAsync("https://nbomber.com");

                return response.IsSuccessStatusCode
                    ? Response.Ok()
                    : Response.Fail();
            })
            .WithoutWarmUp()
            .WithLoadSimulations(
                Simulation.Inject(rate: 10,
                                  interval: TimeSpan.FromSeconds(1),
                                  during: TimeSpan.FromSeconds(30))
            );

            NBomberRunner
                .RegisterScenarios(scenario)
                .Run();
        }
    }
}

Now, let's add more requests. NBomber uses the Load Simulation concept to configure concurrency. Also, you can ramp the number of requests up and down during the test. To configure ramping, use the RampingInject simulation.

// In this example, we configure 
// (RampingInject) - ramp up from 0 to 200 requests per second for 1 minute,
// (Inject) - then we keep the rate of 200 for the next 30 sec.*

.WithLoadSimulations(
    Simulation.RampingInject(rate: 200, 
                             interval: TimeSpan.FromSeconds(1),
                             during: TimeSpan.FromMinutes(1)),
    
    Simulation.Inject(rate: 200,
                      interval: TimeSpan.FromSeconds(1),
                      during: TimeSpan.FromSeconds(30))
);

Create production-ready HTTP load test

Now, you got a basic understanding of NBomber and ready to move on. This time we will use:

• NBomber.Http - plugin to simplify defining and handling of HTTP

To proceed we only need to install NBomber.Http package.

dotnet add package NBomber.Http

This plugin helps you to construct HTTP request messages and send them.

Program.cs

using System;
using System.Threading.Tasks;
using System.Net.Http;

using NBomber.CSharp;
using NBomber.Http.CSharp;

namespace NBomberTest
{
    class Program
    {
        static void Main(string[] args)
        {
            using var httpClient = new HttpClient();

            var scenario = Scenario.Create("http_scenario", async context =>
            {
                var request =
                    Http.CreateRequest("GET", "https://nbomber.com")
                        .WithHeader("Accept", "text/html");
                        // .WithHeader("Accept", "application/json")
                        // .WithBody(new StringContent("{ id: 1 }", Encoding.UTF8, "application/json");
                        // .WithBody(new ByteArrayContent(new [] {1,2,3}))
                        

                var response = await Http.Send(httpClient, request);

                return response;
            })
            .WithoutWarmUp()
            .WithLoadSimulations(
                Simulation.Inject(rate: 100, 
                                  interval: TimeSpan.FromSeconds(1),
                                  during: TimeSpan.FromSeconds(30))
            );

            NBomberRunner
                .RegisterScenarios(scenario)
                .Run();
            }
    }
}

Congratulations! You have done it!

Finally, you reach this point! Here you can find additional information which helps you in building real world NBomber tests:

• Examples