Py Testing — Free Python Tutorial

TL;DR: Learn Py Testing in Python with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.

Py Testing in Python

Unit testing verifies individual functions work correctly. Professional code is always tested — code without tests is rarely accepted in the industry.

Python's unittest module is built-in. pytest is the industry standard (simpler syntax, auto-discovery). Both use the assert-based pattern.

Test-Driven Development (TDD): write the test FIRST, then write code to make it pass. Forces clarity about what a function should do before writing it.

import unittest

class TestMyFunction(unittest.TestCase):
    def setUp(self): ...        # runs before each test
    def test_basic(self):
        self.assertEqual(add(2,3), 5)
        self.assertRaises(ValueError, fn, bad_input)
    def tearDown(self): ...     # runs after each test

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