alchemy-mock 0.4.3

SQLAlchemy mock helpers.

SQLAlchemy mock helpers.

• Free software: MIT license

• GitHub: https://github.com/miki725/alchemy-mock

Installing

You can install alchemy-mock using pip:

$ pip install alchemy-mock

Why?

SQLAlchemy is awesome. Unittests are great. Accessing DB during tests - not so much. This library provides easy way to mock SQLAlchemy’s session in unittests while preserving ability to do sane asserts. Normally SQLAlchemy’s expressions cannot be easily compared as comparison on binary expression produces yet another binary expression:

>>> type((Model.foo == 5) == (Model.bar == 5))
<class 'sqlalchemy.sql.elements.BinaryExpression'>

But they can be compared with this library:

>>> ExpressionMatcher(Model.foo == 5) == (Model.bar == 5)
False

Using

ExpressionMatcher can be directly used:

>>> from alchemy_mock.comparison import ExpressionMatcher
>>> ExpressionMatcher(Model.foo == 5) == (Model.foo == 5)
True

Alternatively AlchemyMagicMock can be used to mock out SQLAlchemy session:

>>> from alchemy_mock.mocking import AlchemyMagicMock
>>> session = AlchemyMagicMock()
>>> session.query(Model).filter(Model.foo == 5).all()

>>> session.query.return_value.filter.assert_called_once_with(Model.foo == 5)

In real world though session can be interacted with multiple times to query some data. In those cases UnifiedAlchemyMagicMock can be used which combines various calls for easier assertions:

>>> from alchemy_mock.mocking import UnifiedAlchemyMagicMock
>>> session = UnifiedAlchemyMagicMock()

>>> m = session.query(Model)
>>> q = m.filter(Model.foo == 5)
>>> if condition:
...     q = q.filter(Model.bar > 10).all()
>>> data1 = q.all()
>>> data2 = m.filter(Model.note == 'hello world').all()

>>> session.filter.assert_has_calls([
...     mock.call(Model.foo == 5, Model.bar > 10),
...     mock.call(Model.note == 'hello world'),
... ])

Also real-data can be stubbed by criteria:

>>> from alchemy_mock.mocking import UnifiedAlchemyMagicMock
>>> session = UnifiedAlchemyMagicMock(data=[
...     (
...         [mock.call.query(Model),
...          mock.call.filter(Model.foo == 5, Model.bar > 10)],
...         [Model(foo=5, bar=11)]
...     ),
...     (
...         [mock.call.query(Model),
...          mock.call.filter(Model.note == 'hello world')],
...         [Model(note='hello world')]
...     ),
...     (
...         [mock.call.query(AnotherModel),
...          mock.call.filter(Model.foo == 5, Model.bar > 10)],
...         [AnotherModel(foo=5, bar=17)]
...     ),
... ])
>>> session.query(Model).filter(Model.foo == 5).filter(Model.bar > 10).all()
[Model(foo=5, bar=11)]
>>> session.query(Model).filter(Model.note == 'hello world').all()
[Model(note='hello world')]
>>> session.query(AnotherModel).filter(Model.foo == 5).filter(Model.bar > 10).all()
[AnotherModel(foo=5, bar=17)]
>>> session.query(AnotherModel).filter(Model.note == 'hello world').all()
[]

Finally UnifiedAlchemyMagicMock can partially fake session mutations such as session.add(instance). For example:

>>> session = UnifiedAlchemyMagicMock()
>>> session.add(Model(pk=1, foo='bar'))
>>> session.add(Model(pk=2, foo='baz'))
>>> session.query(Model).all()
[Model(foo='bar'), Model(foo='baz')]
>>> session.query(Model).get(1)
Model(foo='bar')
>>> session.query(Model).get(2)
Model(foo='baz')

Note that its partially correct since if added models are filtered on, session is unable to actually apply any filters so it returns everything:

>>> session.query(Model).filter(Model.foo == 'bar').all()
[Model(foo='bar'), Model(foo='baz')]

History

0.4.3 (2019-11-05)

• Unifying distinct.

0.4.2 (2019-09-25)

• Adding support label() in ExpressionMatcher. For example column.label('foo').

0.4.1 (2019-06-26)

• Adding support for one_or_none(). Thanks @davidroeca

0.4.0 (2019-06-06)

• Adding basic mutation capability with add and add_all.

0.3.5 (2019-04-13)

• Fixing compatibility with latest mock.

0.3.4 (2018-10-03)

• Unifying limit.

0.3.3 (2018-09-17)

• Unifying options and group_by.

0.3.2 (2018-06-27)

• Added support for count() and get() between boundaries.

0.3.1 (2018-03-28)

• Added support for func calls in ExpressionMatcher. For example func.lower(column).

0.3.0 (2018-01-24)

• Added support for .one() and .first() methods when stubbing data.

• Fixed bug which incorrectly unified methods after iterating on mock.

0.2.0 (2018-01-13)

• Added ability to stub real-data by filtering criteria. See #2.

0.1.1 (2018-01-12)

• Fixed alembic typo in README. oops.

0.1.0 (2018-01-12)

• First release on PyPI.

Credits

Development Lead

• Miroslav Shubernetskiy - https://github.com/miki725

Contributors

• Serkan Hoscai - https://github.com/shosca

License

The MIT License (MIT)

Copyright (c) 2018, Miroslav Shubernetskiy

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
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copies of the Software, and to permit persons to whom the Software is
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The above copyright notice and this permission notice shall be included in
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