unittest vs xUnit.net

Free and open source

Free and open source

Free and open source. You pay in engineering time and CI minutes.

Free and open source. You pay in engineering time and CI minutes.

Everything, self-hosted

Everything, self-hosted

Widely used

Python Software Foundation · since 2001

Category standard

.NET Foundation · since 2007

• In the standard library — nothing to install or vet.
• unittest.mock is excellent and used almost universally in Python.
• Familiar to anyone coming from JUnit or NUnit.

• Per-test instance isolation eliminates a whole class of shared-state bugs by design.
• Idiomatic modern C# — no attribute soup.
• The default in current .NET project templates.

• Verbose compared to pytest for the same coverage.
• No parametrisation or fixture composition worth the name.
• Most teams run unittest tests through pytest anyway.

• Fewer built-in assertions than NUnit; most teams add FluentAssertions.
• The isolation model surprises developers migrating from NUnit.
• Parallelism defaults occasionally bite on integration tests.

Standard-library-only environments and codebases that already use it.

New .NET projects.