`assert_called`¶

So far, we have used the return values of a mocking method to ensure that our application code handles the return values correctly. However, sometimes there is no useful return value, for example, with tasks add some tasks -o veit. In such cases, we can use assert_called_with() to check whether the mock object was called correctly. After calling tasks_cli("add some tasks -o veit"), we do not use the API to check whether the item has been added to the database; instead, we use a mock to ensure that the CLI has correctly called the correct API method. The implementation of the add() command ultimately calls db.add_task() with a Task object:

def test_add_with_owner(mock_tasksdb, tasks_cli):
    tasks_cli("add some task -o veit")
    expected = tasks.Task("some task", owner="veit", state="todo")
    mock_tasksdb.add_task.assert_called_with(expected)

If add_task() is not called, or is called with the wrong type or the wrong object content, the test fails. For example, if we capitalise the string Veit in the expected section but not in the CLI call, we get the following output:

$ uv run pytest -s tests/cli/test_add.py::test_add_with_owner
============================= test session starts ==============================
...
configfile: pyproject.toml
plugins: cov-4.1.0, Faker-19.11.0
collected 1 item

tests/cli/test_add.py F
...
>           raise AssertionError(_error_message()) from cause
E           AssertionError: expected call not found.
E           Expected: add_task(Task(summary='some task', owner='Veit', state='todo', id=None))
E           Actual: add_task(Task(summary='some task', owner='veit', state='todo', id=None))
...
=========================== short test summary info ============================
FAILED tests/cli/test_add.py::test_add_with_owner - AssertionError: expected call not found.
============================== 1 failed in 0.08s ===============================

assert_called¶

`assert_called`¶