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assert_object#

The assert_object module exposes a function that asserts whether the content of a Python object (including possibly nested objects) fulfills provided expectations.

Basic Example#

Consider the following code snippet, which asserts the return value of fun() against specific expectations.

  • The object must have at least two attributes: created_at and books.
  • The created_at attribute, when stringified, must match '2020-06-08 12:30:00'.
  • The books attribute must be an iterable with exactly two elements.
  • The order of the books elements does not matter.
  • One of the books elements must have at least name, authors, and translations attributes.
  • Another books element must have at least name, authors, and language attributes.
  • The values of the books elements' attributes are also checked against specified expectations.
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expectation = ObjectAttributes(
    {
        'created_at': Stringified('2020-06-08 12:30:00'),
        'books': Unordered(
            [
                ObjectAttributes(
                    {
                        'name': 'Otworzyć po mojej śmierci',
                        'authors': ['Abelard Giza'],
                        'translations': MappingSubset({}),
                    },
                ),
                ObjectAttributes(
                    {
                        'name': 'Hobbit',
                        'authors': Stringified("['J. R. R. Tolkien']"),
                        'language': 'en',
                    },
                ),
            ],
        ),
    },
)

assert_object(expectation, foo())

Example of an object that fulfills the above expectation:

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Munch(
    list_author='Jan Kowalski',
    created_at=datetime(2020, 6, 8, 12, 30),
    books=[
        Munch(
            name='Hobbit',
            authors=['J. R. R. Tolkien'],
            language='en',
            translations={'pl': 1963, 'it': 1973},
        ),
        Munch(
            name='Otworzyć po mojej śmierci',
            authors=['Abelard Giza'],
            language='pl',
            translations={},
        ),
    ],
)