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Fluent Assertions

A very extensive set of extension methods that allow you to more naturally specify the expected outcome of a TDD or BDD-style unit tests. Targets .NET Framework 4.7, as well as .NET Core 2.1, .NET Core 3.0, .NET 6, .NET Standard 2.0 and 2.1.

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Intention-Revealing Unit Tests

Write assertions that keep you and your fellow developers out of the debugger hell and clearly communicate what they are trying to accomplish.

Comprehensive Documentation

Extensive documentation to help you understand the power of the assertions and learn finding the sweet spot of well-written unit tests.

Highly Extensible

Many documented extension points and overridable behavior that provides enough flexibility for even the most critical developer.

Feature Complete

Targets .NET 4.7, .NET Core 2.1, .Net Core 3.0, .NET 6, .NET Standard 2.0 and 2.1. Supports MSTest2, xUnit2, NUnit3, MSpec and NSpec3.

Great Support

Use  StackOverflow for general questions, go on  Slack to contact the team directly, or visit  GitHub for issues & feature requests.

Passionate Team

Originally authored by Dennis Doomen, but Jonas Nyrup has joined since then. Notable contributions by Michaël Hompus and Gunnar Liljas.

Reliable and Assertive Testing Library

Fluent Assertions for .NET empowers developers with an expressive syntax to write readable and maintainable assertions in unit tests. Trusted by leading organizations, it seamlessly integrates with popular testing frameworks such as MSTest, NUnit, and xUnit. 

One of the standout features of Fluent Assertions is its ease of use. The syntax is designed to be highly readable, making it easy for developers to understand what the test is verifying at a glance. This clarity not only improves the maintainability of tests but also enhances collaboration among team members. When you read a test written with Fluent Assertions, it is immediately clear what the expected outcome is, reducing the cognitive load required to comprehend the test logic. This makes code reviews and debugging more efficient, contributing to overall productivity.

Key Features

• Readable and Fluent Syntax: Write assertions that are easy to read and understand. This makes the code more maintainable and reduces the time spent on debugging. 
• Extensive Matcher Support: Covers a wide range of matchers to cater to various testing needs, from simple value comparisons to complex object graphs. 
• Supports .NET 4.5 and Above: Fully compatible with .NET Core, .NET 5, 6, and 7, ensuring it fits into modern development environments.

Comprehensive Testing

Fluent Assertions offers a comprehensive set of features that make it easier to write and maintain high-quality unit tests. These include: 
• Detailed Failure Messages: Offers clear and concise failure messages to aid in debugging, making it easier to identify and fix issues quickly. 
• Custom Assertions: Allows the creation of custom assertions tailored to specific needs, providing flexibility and control over the testing process. 
• Advanced Object Graph Comparison: Compare complex object graphs with ease, including nested collections, ensuring that your tests cover all necessary scenarios.

Ease of Use and Public Interface

Fluent Assertions is designed with ease of use in mind. Its fluent syntax makes the code intuitive and easy to read, reducing the learning curve for new developers. The library’s public interface is elegant and straightforward, allowing developers to focus on writing tests without getting bogged down by complex configurations. Some of the key aspects include: 
• Expressive API: Create intuitive and human-readable assertions that clearly convey the intent of the tests. 
• Seamless Integration: Works effortlessly with MSTest, NUnit, xUnit, and other testing frameworks, providing a consistent experience across different projects. 
• Extensible: Easily extend the library with custom assertions to meet the specific needs of your application. 
• Detailed Documentation: Comprehensive documentation integrated into Visual Studio, helping developers quickly find the information they need. 
• Community-Driven: Active development and support from a vibrant community, ensuring the library continues to evolve and improve.

Trusted by Industry Leaders

Fluent Assertions is used by Microsoft, Google, and other Fortune 500 companies, highlighting its reliability and effectiveness. JetBrains, a renowned company in the development tools space, also endorses Fluent Assertions, showcasing its widespread adoption and impact. Here’s how Fluent Assertions contributes to the social credit of these large companies: 
• Trust and Reliability: Used by industry leaders like Microsoft, Google, and JetBrains, which underscores its reliability and effectiveness in ensuring code quality. 
• Code Quality: Helps maintain high standards in code quality, which is crucial for the reputation of any software development team. 
• Community Credibility: Enhances the credibility of companies within the developer community by fostering a culture of excellence and accountability. 
• Industry Leadership: Demonstrates a commitment to adopting best practices and utilizing state-of-the-art tools, further enhancing the company’s standing in the tech industry.

Licensing Options

Fluent Assertions offers flexible licensing options to cater to different needs: 
• 1-Year Subscription: Includes updates and priority support, ensuring that your team has access to the latest features and improvements. 
• Team Packs: Discounts for teams of 10 or 20 members, making it cost-effective for larger teams. 
• Blueprint Subscription: Includes source code and additional customization options, providing full control over the library and the ability to tailor it to specific requirements.

Conclusion

Explore the power of Fluent Assertions and elevate your testing experience to new heights. Its ease of use, extensive feature set, and strong industry endorsement make it an invaluable tool for any .NET development team.

  • 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 4.7, .NET Core 2.1, .Net Core 3.0, .NET 6, .NET Standard 2.0 and 2.1.
  • Supports MSTest2, xUnit2, NUnit3, MSpec and NSpec3.