What is Fluent Assertions?

With Fluent Assertions, the assertions look beautiful, natural and most importantly, extremely readable -Girish

everyone.Should().Like(FluentAssertions, “because everything is so damn cool and readable”); - Jim Speaker and Bart Roozendaal

Fluent Assertions is a set of .NET extension methods that allow you to more naturally specify the expected outcome of unit tests. It offers a plethora of features:

The best assertion framework in the .NET realm. Go to the examples to see for yourself.


Install with NuGet NuGet

PM > Install-Package FluentAssertions


Fluent Assertions 5.1.2 was released on 19 February 2018


  • {Fix} Improve message for unequal length collections in BeEquivalentTo - #766
  • {Fix} Return warning message from BecauseOf when the because phrase cannot be formatted - #764
  • {Fix} Only attempt to format the because phrase if format parameters were supplied - #769
  • {Fix} Handle the case where becauseArgs can be null - #770
  • {Fix} Do not assume test classes to be inside a namespace - #773

View Release on GitHub

How to get help

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Community Extensions

There are a number of community maintained extension projects. The ones we are aware of a listed below. To add yours please fork the repository and send a pull request.

Special thanks

This project would not have been possible without the support of JetBrains. We thank them generously for providing us with the ReSharper licenses necessary to make us productive developers.