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Fluent Assertions

Fluent Assertions offers a comprehensive suite of extension methods that enable developers to naturally express the expected outcomes of TDD (Test-Driven Development) or BDD (Behavior-Driven Development) unit tests. By providing a more readable and intuitive approach to writing assertions, it streamlines the testing process and improves code clarity. It supports a wide range of .NET platforms, including .NET Framework 4.7, .NET 6, as well as .NET Standard 2.0 and 2.1, ensuring compatibility across various modern development environments.

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Intention-Revealing Unit Tests

Write clear and expressive assertions that help you and your team avoid the frustration of complex debugging while effectively conveying the intended behavior of the code being tested.

Comprehensive Documentation

Access detailed, well-structured documentation designed to deepen your understanding of assertions and guide you in crafting precise, high-quality unit tests.

Highly Extensible

Leverage numerous documented extension points and customizable behaviors, offering enough flexibility to meet the specific needs of even the most demanding developers.

Feature Complete

Fully compatible with .NET Framework 4.7, .NET 6, and .NET Standard 2.0 and 2.1. It supports major testing frameworks, including MSTest2, xUnit2, NUnit3, NUnit4, MSpec, and TUnit, making it a versatile solution for modern .NET development.

Great Support

Get fast and reliable assistance through our chat functionality or by contacting us directly at [email protected]. Our team is here to help you resolve any issues and ensure a smooth experience.

Passionate Team

Originally created by Dennis Doomen and later joined by Jonas Nyrup, Fluent Assertions is now supported and maintained by the talented developers at Xceed. Notable contributions by Michaël Hompus and Gunnar Liljas have played a key role in enhancing the product’s capabilities, ensuring ongoing innovation and excellence.

Get Started !

You can install Fluent Assertions directly from NuGet, or visit the GitHub repository for more details. To add it to your project, simply execute the following command in your terminal from your project folder:

				
					dotnet add package FluentAssertions

For Visual Studio:

  1. Open your project in Visual Studio.
  2. Navigate to the Tools menu and select NuGet Package Manager, then choose Manage NuGet Packages for Solution….
  3. In the NuGet Package Manager window:
    • Go to the Browse tab.
    • Search for FluentAssertions.
    • Select it from the list and click Install for the desired project.
  4. After installation, Fluent Assertions will be added to your project’s dependencies.

A readable, fluent assertion library for .NET

Fluent Assertions gives you a natural, chainable syntax for stating what a unit test expects, whether you write in a TDD or BDD style. A test reads almost like a sentence, so it is clear at a glance what is being verified. That keeps tests easy to maintain and makes failures quicker to diagnose.

Key features

  • Fluent, readable syntax that states intent plainly and keeps tests easy to maintain.
  • A wide set of assertions, from simple value checks to deep object-graph comparison across nested collections.
  • Clear failure messages that say what went wrong and where, so you fix issues without guesswork.
  • Custom assertions when you need them, so you can extend the library to fit your own types.
  • Targets .NET Framework 4.7, .NET 6, and .NET Standard 2.0 and 2.1.
  • Works with MSTest, NUnit 3 and 4, xUnit, MSpec, and TUnit.

Widely adopted

Fluent Assertions is one of the most-used testing libraries in the .NET ecosystem, with more than 750 million downloads on NuGet. JetBrains has covered it in its .NET content, and it ships in the test suites of countless open-source and commercial projects.

Licensing

  • Annual subscription, including updates and priority support.
  • Team packs with volume pricing for teams of 10 or 20 developers.
  • Blueprint subscription with full source code, for teams that need to customize or audit the library.
  • Write assertions that keep you and your fellow developers out of the debugger hell and clearly communicate what they are trying to accomplish.
  • Write assertions that are easy to read and understand. This makes the code more maintainable and reduces the time spent on debugging.
  • Covers a wide range of matchers to cater to various testing needs, from simple value comparisons to complex object graphs
  • Extensive documentation to help you understand the power of the assertions and learn finding the sweet spot of well-written unit tests.
  • Many documented extension points and overridable behavior that provides enough flexibility for even the most critical developer
  • Targets .NET Framework 4.7, .NET 6, and .NET Standard 2.0 and 2.1.
  • Supports MSTest2, xUnit2, NUnit3, NUnit4, MSpec and TUnit.
  • Get fast and reliable assistance through our chat functionality or by contacting us directly at [email protected]. Our team is here to help you resolve any issues and ensure a smooth experience.

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