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.

Grouping Tests

TO PROCESS: https://docs.python.org/3/library/unittest.html#grouping-tests

Test Runner

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

Loading and Running Tests

TO PROCESS: https://docs.python.org/3/library/unittest.html#loading-and-running-tests

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

tearDown()

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

setUpClass()

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

tearDownClass()

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

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

assertMultiLineEqual()

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

assertSequenceEqual()

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

assertListEqual()

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

assertTupleEqual()

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

assertSetEqual()

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

assertDictEqual()

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

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