Unit Testing Basics with unittest is an important beginner topic in real Python work.
This lesson keeps the language simple but professional. You will learn what the concept is, why it matters, and how to apply it safely in small projects.
Detailed explanation of Unit Testing Basics with unittest:
1. Understand the smallest version first.
2. Practice with short examples.
3. Observe outputs and errors carefully.
4. Refactor names so code reads like plain English.
5. Repeat with small daily exercises.
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def add(a, b):
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return a + b
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assert add(2, 3) == 5
Run this example, then change one input and observe what changes.
Example 2
unittest basic case
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import unittest
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class TestMath(unittest.TestCase):
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def test_add(self):
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self.assertEqual(2 + 3, 5)
Run this example, then change one input and observe what changes.
Example 3
Run unittest module
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Example 4
Test exceptions
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import unittest
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class T(unittest.TestCase):
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def test_error(self):
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with self.assertRaises(ValueError):
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int('x')
Run this example, then change one input and observe what changes.
Example 5
pytest style test
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def test_total():
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assert sum([1, 2, 3]) == 6
Run this example, then change one input and observe what changes.
Run this example, then change one input and observe what changes.
Example 7
Arrange-Act-Assert pattern
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value = 2
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result = value * 3
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assert result == 6
Run this example, then change one input and observe what changes.
Example 8
Test string function
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def shout(s):
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return s.upper()
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assert shout('hi') == 'HI'
Run this example, then change one input and observe what changes.
Example 9
Param-like checks
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for a, b, expected in [(1,2,3),(2,2,4)]:
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assert a+b == expected
Run this example, then change one input and observe what changes.
Example 10
Test file existence
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from pathlib import Path
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assert Path('requirements.txt').exists()
Run this example, then change one input and observe what changes.
