Technical Story: https://github.com/SSWConsulting/SSW.CleanArchitecture/pull/497

Context and Problem Statement¶

We have been using FluentAssertions for our unit tests.

This library is great however, the project has now switched to a paid model. Versions 8 and beyond are free for open-source projects and non-commercial use, but commercial use requires a paid licence.

Version 7 will remain fully open-source indefinitely and receive bugfixes and other important corrections.

Decision Drivers¶

• Free for commercial use
• Concise and readable assertions

Considered Options¶

1. Shouldly
2. Fluent Assertions (free version)
3. Fluent Assertions (paid version)
4. Native test framework assertions (e.g. xUnit/NUnit/TUnit)
5. Awesome Assertions

Decision Outcome¶

Chosen option: "Option 5 - Awesome Assertions", because we get the same experience as FluentAssertions, but it is free for commercial use. It is also easy to migrate from FluentAssertions to Awesome Assertions.

Pros and Cons of the Options ¶

Option 1 - Shouldly¶

https://docs.shouldly.org/

• ✅ Good assertion library
• ✅ Free for commercial use
• ❌ Would require a lot of work to migrate from FluentAssertions
• ❌ Custom extensions would need to be rewritten

Option 2 - Fluent Assertions (free version)¶

https://xceed.com/products/unit-testing/fluent-assertions/

• ✅ Great assertion library
• ✅ Version 7 is Free for open-source projects and non-commercial use
• ❌ Easy to upgrade to version 8, resulting in substantial licence fees

Option 3 - Fluent Assertions (paid version)¶

https://xceed.com/products/unit-testing/fluent-assertions/

• ✅ Great assertion library
• ❌ Substantial licence fees for commercial use. ($130 per developer per year. For SSW this would cost $7,410 per year for 57 developers)

Option 4 - Native test framework assertions (e.g. xUnit/NUnit/TUnit)¶

• ✅ Free for commercial use
• ✅ No additional dependencies
• ❌ Assertions are not as readable as FluentAssertions
• ❌ Would require a lot of work to migrate from FluentAssertions
• ❌ Custom extensions would need to be rewritten

Option 5 - Awesome Assertions¶

https://awesomeassertions.org/

• ✅ Great assertion library
• ✅ Free for commercial use
• ✅ Easy to migrate from FluentAssertions
• ✅ Custom extensions will continue to work (with minor modifications)