--- title: Learn Python Testing in 15 minutes (Unittest vs Pytest) description: A practical comparison of Python's built-in unittest module and pytest, using a simple calculator class as the test subject. Covers the boilerplate-heavy... canonical: https://daily.dev/posts/learn-python-testing-in-15-minutes-unittest-vs-pytest--lg95ubdat twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Learn Python Testing in 15 minutes (Unittest vs Pytest) | daily.dev og:description: A practical comparison of Python's built-in unittest module and pytest, using a simple calculator class as the test subject. Covers the boilerplate-heavy... og:url: https://daily.dev/posts/learn-python-testing-in-15-minutes-unittest-vs-pytest--lg95ubdat og:image: https://api.daily.dev/og/posts/lG95ubDat.png og:image:alt: Learn Python Testing in 15 minutes (Unittest vs Pytest) og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Learn Python Testing in 15 minutes (Unittest vs Pytest) **[Indently](https://daily.dev/sources/indently)** · 15 min read · 1 upvotes · 0 comments ## Summary A practical comparison of Python's built-in unittest module and pytest, using a simple calculator class as the test subject. Covers the boilerplate-heavy unittest approach (subclassing TestCase, setup methods, assert equal) versus pytest's cleaner style (plain functions, fixtures, plain assert statements). Demonstrates pytest's parametrize decorator for running multiple test cases with a single function, edge case testing with pytest.raises, and how pytest provides detailed failure output. Concludes with a side-by-side summary of both frameworks. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What are the main differences between pytest and unittest in Python? Pytest uses plain functions instead of TestCase subclasses, plain assert statements instead of assertEqual, and opt-in fixtures instead of setUp methods. It also provides pytest.raises with a match argument for checking exception messages, and the parametrize decorator to run one test function across a table of inputs instead of writing duplicate test methods, as unittest requires. _Developers weighing pytest against unittest can find comparisons like this one on daily.dev._ ### How do you test that a function raises an exception with a specific error message in pytest? Use the pytest.raises context manager with the expected exception type, and add the match argument set to a string or regex that the error message must match, for example pytest.raises(ValueError, match="cannot divide by zero"). This checks both that the exception type is raised and that its message matches the given text in one step. _Anyone writing exception tests in Python can track patterns like this via daily.dev._ ### How do you run multiple test cases with different inputs using one pytest function? Use the pytest.mark.parametrize decorator, providing the names of the parameters as a string and a list of tuples where each tuple represents one test case's values. Pytest then runs the decorated test function once per tuple, labeling each run clearly in the output, so a single function can cover many input combinations, such as seven arithmetic cases in one test. _Developers reducing test duplication with parametrize can keep up with such techniques on daily.dev._ ## Similar posts on daily.dev - [Testing Your Code With Python's unittest – Real Python](https://daily.dev/posts/testing-your-code-with-python-s-unittest-real-python-kb6n0cqus) · Real Python · 0 upvotes · 0 comments - [Django's test runner is underrated](https://daily.dev/posts/django-s-test-runner-is-underrated-z3oosjhgz) · Planet Python · 1 upvotes · 0 comments - [Improving Your Tests With the Python Mock Object Library – Real Python](https://daily.dev/posts/improving-your-tests-with-the-python-mock-object-library-real-python-elbphcay1) · Real Python · 0 upvotes · 0 comments - [How to get more from Python integration testing](https://daily.dev/posts/how-to-get-more-from-python-integration-testing-obvsb128r) · Honeybadger · 0 upvotes · 0 comments - [Test-Driven Development With pytest Quiz – Real Python](https://daily.dev/posts/test-driven-development-with-pytest-quiz-real-python-eqjpaowzy) · Real Python · 0 upvotes · 0 comments --- Tags: [#python](https://daily.dev/tags/python), [#testing](https://daily.dev/tags/testing) [View this post on daily.dev](https://daily.dev/posts/learn-python-testing-in-15-minutes-unittest-vs-pytest--lg95ubdat) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Learn Python Testing in 15 minutes (Unittest vs Pytest)","url":"https://daily.dev/posts/learn-python-testing-in-15-minutes-unittest-vs-pytest--lg95ubdat","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/learn-python-testing-in-15-minutes-unittest-vs-pytest--lg95ubdat"},"datePublished":"2026-07-23T16:22:41.905Z","dateModified":"2026-09-14T06:27:18.010Z","description":"A practical comparison of Python's built-in unittest module and pytest, using a simple calculator class as the test subject. 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