Python Module unittest

External

• https://docs.python.org/3/library/unittest.html#module-unittest

Internal

• Python Language
• Python Testing

unittest vs. pytest

TODO: https://www.pythonpool.com/python-unittest-vs-pytest/

Concepts

Test Fixture

A test fixture represents the code needed to prepare the context for running one or more tests (create temporary databases, directories, etc.), and any associated cleanup actions.

Test Case

A test case is the individual unit of testing. In unittest, the test cases inherit from the base class TestCase.

Test Suite

A collection of test cases, test suites or both.

Test Runner

The test runner is the component that orchestrates the execution of tests and provides the outcomes to the user.

Organizing Test Code

TO PROCESS: https://docs.python.org/3/library/unittest.html#organizing-test-code

API

TestCase

A simple test case can be implemented by subclassing TestCase as shown below. The individual test methods are have names that start with test. This is a naming convention that informs the test runner about which methods to invoke as tests.

from unittest import TestCase

from my_code_to_test import some_function


class TestMyCode(TestCase):

    def test_empty(self):
        self.assertFalse(some_function(''))

    def test_lower_case(self):
        self.assertEqual('A', some_function('a'))

    def test_upper_case(self):
        self.assertEqual('A', some_function('A'))

    def test_exception(self):
        with self.assertRaises(ValueError):
            some_function('special')

Setup and Teardown

setUp() and tearDown() define instructions to be executed before and after each test method execution.

setUp()

https://docs.python.org/3/library/unittest.html#unittest.TestCase.setUp

Assertion Methods

These methods are used instead of the assert statement so the test runner can accumulate all test results and produce a report. Really? pytest can produce reports and it uses assert.

assertEquals()

https://docs.python.org/3/library/unittest.html#unittest.TestCase.assertEqual

assertTrue()

https://docs.python.org/3/library/unittest.html#unittest.TestCase.assertTrue

assertFalse()

https://docs.python.org/3/library/unittest.html#unittest.TestCase.assertFalse

assertRaises()

https://docs.python.org/3/library/unittest.html#unittest.TestCase.assertRaises

Operations

Command Line Syntax

Running tests from command line:

python -m unittest test_module_1 test_module_2
python -m unittest test_module.TestClass
python -m unittest test_module.TestClass.test_method
python -m unittest tests/test_something.py # The file must be still importable as a module.

More verbosity: command line parameter -v.

If the unittest module is executed without arguments, the module invokes test discovery.

Command Line Options

https://docs.python.org/3/library/unittest.html#command-line-options

Test Discovery

https://docs.python.org/3/library/unittest.html#test-discovery

Run the unittest module without arguments:

python -m unittest

TO PROCESS: https://docs.python.org/3/library/unittest.html#test-discovery

Other Subjects

Skipping Tests and Expected Failures

TO PROCESS: https://docs.python.org/3/library/unittest.html#skipping-tests-and-expected-failures

Distinguishing Test Iterations using Subtests

TO PROCESS: https://docs.python.org/3/library/unittest.html#distinguishing-test-iterations-using-subtests