unittest

The unittest unit testing framework was originally inspired by JUnit and has a similar flavor as major unit testing frameworks in other languages. It supports test automation, sharing of setup and shutdown code for tests, aggregation of tests into collections, and independence of the tests from the reporting framework.

Mock⚑

unittest.mock is a library for testing in Python. It allows you to replace parts of your system under test with mock objects and make assertions about how they have been used.

Usage⚑

First, from unittest.mock import patch. Then set the appropriate decorator for the function and expect a new argument related to the mock object. This object will have methods such as:

• assert_called: assert that the mock was called at least once.
• assert_called_once: assert that the mock was called exactly once.
• assert_called_with: asserts that the last call has been made in a particular way.
• assert_called_once_with: assert that the mock was called exactly once and that call was with the specified arguments.

And attributes such as:

• call_args: either None (if the mock hasn't been called), or the arguments that the mock was last called with.

Function⚑

Use @patch("{{function}}", {{return_value}}).

Class Method⚑

Use @patch.object({{class}}, {{method}}, return_value={{return_value}}).

For example:

@patch.object(SomeClass, 'class_method')
def test(mock_method):
    SomeClass.class_method(3)
    mock_method.assert_called_with(3)

test()

Abstract class⚑

To patch an abstract class to be able to instantiate it, without having to create a fake class that inherits from it, you can patch it as follows:

@patch.object(MyAbcClass, '__abstractmethods__', set())

or if you want to patch some attributes and/or methods at the same time:

@patch.multiple(MyAbcClass, __abstractmethods__=set())