unittest vs RSpec

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

Widely used

RSpec Team · since 2005

• 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.

• The output reads as documentation of intended behaviour.
• Shared examples and contexts keep large Rails suites organised.
• Deep integration with the Rails ecosystem — Capybara, FactoryBot, VCR.

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

• Deeply nested contexts with let and before hooks become very hard to follow.
• The DSL is a language of its own to learn.
• Rails suites tend towards slowness; expect to invest in parallelisation.

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

Ruby and Rails applications.