Comparison between pytest and unittes test frameworks

For example, the test_decrement functions given earlier are failing because the assertion itself is faulty.

Once VS Code recognizes tests, it provides several ways to run those tests

You can trigger test discovery at any time using the Python: Discover Tests command.

Testing in Python is disabled by default. To enable testing, use the Python: Configure Tests command on the Command Palette.

python.testing.unittestArgs: Looks for any Python (.py) file with "test" in the name in the top-level project folder.

Create a file named test_unittest.py that contains a test class with two test methods

import inc_dec    # The code to test
import unittest   # The test framework

class Test_TestIncrementDecrement(unittest.TestCase):
    def test_increment(self):
        self.assertEqual(inc_dec.increment(3), 4) # checks if the results is 4 when x = 3

    def test_decrement(self):
        self.assertEqual(inc_dec.decrement(3), 4)

if __name__ == '__main__':
    unittest.main()

Each test framework has its own conventions for naming test files and structuring the tests within, as described in the following sections. Each case includes two test methods, one of which is intentionally set to fail for the purposes of demonstration.

Nose2, the successor to Nose, is just unittest with plugins

Python tests are Python classes that reside in separate files from the code being tested.

general background on unit testing, see Unit Testing on Wikipedia. For a variety of useful unit test examples, see https://github.com/gwtw/py-sorting

Running the unit test early and often means that you quickly catch regressions, which are unexpected changes in the behavior of code that previously passed all its unit tests.

Developers typically run unit tests even before committing code to a repository; gated check-in systems can also run unit tests before merging a commit.

in unit testing you avoid external dependencies and use mock data or otherwise simulated inputs

The practice of test-driven development is where you actually write the tests first, then write the code to pass more and more tests until all of them pass.

The combined results of all the tests is your test report

each test is very simple: invoke the function with an argument and assert the expected return value.

    def test_validator_valid_string():
        # The exact assertion call depends on the framework as well
        assert(validate_account_number_format("1234567890"), true)

Unit tests are concerned only with the unit's interface—its arguments and return values—not with its implementation

unit is a specific piece of code to be tested, such as a function or a class. Unit tests are then other pieces of code that specifically exercise the code unit with a full range of different inputs, including boundary and edge cases.