Use Python unittest to Master Test-Driven Development
By Avalith Editorial Team ♦ 1 min read
What Are Unit Tests in Python?
Test Driven Development
The Assert Statement and the Python Unittest Module
Built-in Testing Framework: unittest is built into Python, so you won’t need added installations. You can easily access it and use it across different Python environments.
Simple and Familiar Syntax: Like we’ve seen, the unittest framework uses a class-based approach. Test cases are classes that inherit from unittest.TestCase which are intuitive and are already familiar to developers.
Assertion Methods: unittest providesseveral assertion methods to compare expected and actual results.
Test Discovery: Automated test discovery enables the discovery and execution of all test cases within a directory or module.
Test Fixtures: You can define setup and teardown methods within test cases. Methods like setUp() and tearDown() let you set up the environment you need before executing each test and clean up resources once you’re done.
Run Unittest in Python
The assertEqual(a,b) checks that a==b
The assertNotEqual(a,b) checks that a != b
The assertTrue(x) checks that bool(x) is True
The assertFalse(x) checks that bool(x) is False
The assertIs(a,b) checks that a is b
The assertIsNot(a, b) checks that a is not b
The assertIsNone(x) checks that x is None
The assertIsNotNone(x) checks that x is not None
The assertIn(a, b) checks that a in b
The assertNotIn(a, b) checks that a not in b
The assertIsInstance(a, b) checks that isinstance(a, b)
The assertNotIsInstance(a, b) checks that not isinstance(a, b)
Differences Between PyTest and Unittest
Test Discovery: Pytest allows for automatic test discovery, and can find and run tests without boilerplate, while Unittest requires manual discovery and explicitly defining test cases
Fixture Support: Pytest has powerful, flexible fixture support while Unittest offers limited fixture support through setup and teardown methods
Test Execution: Pytest supports parallel test execution and a faster runtime while Unittest supports a sequential test execution, meaning you can run one test at a time
Test Execution Options: Pytest provides options for test execution customization while Unittest offers fewer options for customizing your testing
Assertion Methods: Pytest has a series of built-in assertion methods while Unittest has the standard assertion methods provided by the unittest module
Test Organization: Python’s test functions can be organized in different ways, while Unittest cases are organized as classes, providing a more structured approach
Skipping Tests: Pytest has a built-in mechanism for skipping tests, while Unittest lets you skip using decorators or conditional statements
Test Parameterization: With PyTest, you get built-in support for parameterized tests but parameterization can be achieved using decorators or conditional logic with Unittest
Plugin Ecosystem: PyTest boasts a large and active plugin ecosystem, Unittest has limited plugin support, fewer third-party extensions, etc.
Output Readability: PyTest provides you with detailed and readable output for failed tests, Unittest provides a basic output with less details
Integration with IDEs: PyTest integrates well with various IDEs, plugins, and reporting tools but Unittest provides basic integration
Python Version Support: PyTest is compatible with Python 2.7 and above, Unittest is compatible with Python 2.1 and above