unittest vs Testing Library

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

OSS community · since 2018

• 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.

• Tests survive refactors because they assert on user-visible output, not internals.
• Accessible-role queries push teams towards accessible markup as a side effect.
• One idiom across every major front-end framework.

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

• Deliberately makes implementation-detail testing hard, which frustrates teams used to shallow rendering.
• Async utilities and act() warnings are a common source of confusion.
• Needs a runner and a DOM environment alongside it.

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

Any front-end team writing component tests, regardless of framework.