From SpecFlow to Reqnroll (BDD)

SpecFlow, one of the most widely used BDD frameworks for .NET, has seen its open-source development slow down after being acquired by Tricentis. While originally developed as the .NET counterpart to Cucumber, bringing Behavior-Driven Development (BDD) to the .NET ecosystem, its updates became less frequent, raising concerns within the community. Although Tricentis still provides some level of support, its focus has shifted toward commercial solutions, prompting many development teams to search for an actively maintained alternative.

To address this need, the Reqnroll project was created as a fork of SpecFlow, ensuring continuity for .NET BDD practitioners. The Reqnroll team has publicly stated its commitment to maintaining and improving the framework while ensuring compatibility with existing SpecFlow tests (source). Reqnroll retains full backward compatibility while providing ongoing support and enhancements for modern .NET applications, making it a natural successor for teams looking to future-proof their BDD workflows.

What is BDD and Why is it Important?

Behavior-Driven Development (BDD) is an agile methodology that enhances collaboration between developers, testers, and business stakeholders. It focuses on defining application behavior in plain language scenarios, ensuring clarity on how the system should function.

BDD uses Gherkin syntax to describe test cases in a human-readable format:

Feature: Shopping Cart
  As a customer
  I want to add items to my shopping cart
  So that I can purchase them later

  Scenario: Add an item to the cart
    Given I have an empty shopping cart
    When I add a "Laptop" to the cart
    Then the cart should contain 1 item

BDD frameworks like SpecFlow (and now Reqnroll) enable teams to automate these scenarios using C# step definitions, bridging the gap between business requirements and code.

Why Reqnroll?

Reqnroll is a direct fork of SpecFlow, created to provide an actively maintained alternative for .NET teams. The benefits of switching to Reqnroll include:

• Same Feature Set – It works just like SpecFlow, supporting Gherkin syntax and test automation.
• Seamless Migration – Existing SpecFlow tests require minimal changes.
• Ongoing Support – Unlike SpecFlow, Reqnroll is actively maintained with updates for the latest .NET versions.

Writing Step Definitions in Reqnroll

Reqnroll uses step definitions to bind Gherkin scenarios to C# methods. Below is a sample implementation of the shopping cart scenario:

using NUnit.Framework;
using Reqnroll;
using System.Collections.Generic;

namespace MyStore.Tests.StepDefinitions
{
    [Binding]
    public class ShoppingCartSteps
    {
        private List<string> _cart;

        [Given("I have an empty shopping cart")]
        public void GivenIHaveAnEmptyShoppingCart()
        {
            _cart = new List<string>();
        }

        [When("I add a \"(.*)\" to the cart")]
        public void WhenIAddAnItemToTheCart(string item)
        {
            _cart.Add(item);
        }

        [Then("the cart should contain (.*) item")]
        public void ThenTheCartShouldContainItem(int count)
        {
            Assert.AreEqual(count, _cart.Count);
        }
    }
}

These step definitions map directly to the Gherkin steps in the .feature file, allowing Reqnroll to execute BDD scenarios.

Using Hooks in Reqnroll

Reqnroll supports BeforeScenario and AfterScenario hooks, just like SpecFlow:

using Reqnroll;
using NUnit.Framework;

namespace MyStore.Tests
{
    [Binding]
    public class Hooks
    {
        [BeforeScenario]
        public void BeforeScenario()
        {
            TestContext.WriteLine("Starting test...");
        }

        [AfterScenario]
        public void AfterScenario()
        {
            TestContext.WriteLine("Test finished.");
        }
    }
}

Dependency Injection in Reqnroll

Reqnroll fully supports .NET Dependency Injection for injecting services into step definitions:

using Reqnroll;
using MyStore.Services;

[Binding]
public class ShoppingCartSteps
{
    private readonly ShoppingCartService _cartService;

    public ShoppingCartSteps(ShoppingCartService cartService)
    {
        _cartService = cartService;
    }

    [When("I add a \"(.*)\" to the cart")]
    public void WhenIAddAnItemToTheCart(string item)
    {
        _cartService.AddItem(item);
    }
}

Migrating from SpecFlow to Reqnroll

The migration process is simple, as Reqnroll is a 1:1 replacement for SpecFlow. To switch:

1. Replace SpecFlow NuGet Packages with Reqnroll equivalents.
2. Update Namespaces from TechTalk.SpecFlow to Reqnroll.
3. Run Your Tests – Everything should work as before.

Conclusion

With SpecFlow’s open-source development slowing down, Reqnroll emerges as the natural successor, ensuring that .NET teams can continue using BDD without disruption. If you were using SpecFlow, switching to Reqnroll is straightforward and guarantees long-term support for your BDD testing framework.

Reqnroll keeps the Given/When/Then workflow intact, allowing teams to maintain collaboration, improve test coverage, and ensure software meets business expectations. If your project relied on SpecFlow, Reqnroll is the way forward.