Alexander Hess
f996376b13
- add Grid, Pixel, and AddressPixelAssociation ORM models - each Grid belongs to a City an is characterized by the side_length of all the square Pixels contained in it - Pixels aggregate Addresses => many-to-many relationship (that is modeled with SQLAlchemy's Association Pattern to implement a couple of constraints)
90 lines
2.7 KiB
Python
90 lines
2.7 KiB
Python
"""Test the ORM's `Pixel` model."""
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# pylint:disable=no-self-use
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import pytest
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import sqlalchemy as sqla
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from sqlalchemy import exc as sa_exc
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from urban_meal_delivery import db
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class TestSpecialMethods:
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"""Test special methods in `Pixel`."""
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def test_create_pixel(self, pixel):
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"""Test instantiation of a new `Pixel` object."""
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assert pixel is not None
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def test_text_representation(self, pixel):
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"""`Pixel` has a non-literal text representation."""
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result = repr(pixel)
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assert result == f'<Pixel: ({pixel.n_x}, {pixel.n_y})>'
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@pytest.mark.db
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@pytest.mark.no_cover
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class TestConstraints:
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"""Test the database constraints defined in `Pixel`."""
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def test_insert_into_database(self, db_session, pixel):
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"""Insert an instance into the (empty) database."""
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assert db_session.query(db.Pixel).count() == 0
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db_session.add(pixel)
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db_session.commit()
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assert db_session.query(db.Pixel).count() == 1
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def test_delete_a_referenced_grid(self, db_session, pixel):
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"""Remove a record that is referenced with a FK."""
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db_session.add(pixel)
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db_session.commit()
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# Must delete without ORM as otherwise an UPDATE statement is emitted.
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stmt = sqla.delete(db.Grid).where(db.Grid.id == pixel.grid.id)
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with pytest.raises(
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sa_exc.IntegrityError, match='fk_pixels_to_grids_via_grid_id',
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):
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db_session.execute(stmt)
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def test_negative_n_x(self, db_session, pixel):
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"""Insert an instance with invalid data."""
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pixel.n_x = -1
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db_session.add(pixel)
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with pytest.raises(sa_exc.IntegrityError, match='n_x_is_positive'):
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db_session.commit()
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def test_negative_n_y(self, db_session, pixel):
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"""Insert an instance with invalid data."""
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pixel.n_y = -1
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db_session.add(pixel)
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with pytest.raises(sa_exc.IntegrityError, match='n_y_is_positive'):
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db_session.commit()
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def test_non_unique_coordinates_within_a_grid(self, db_session, pixel):
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"""Insert an instance with invalid data."""
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another_pixel = db.Pixel(grid=pixel.grid, n_x=pixel.n_x, n_y=pixel.n_y)
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db_session.add(another_pixel)
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with pytest.raises(sa_exc.IntegrityError, match='duplicate key value'):
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db_session.commit()
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class TestProperties:
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"""Test properties in `Pixel`."""
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def test_side_length(self, pixel):
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"""Test `Pixel.side_length` property."""
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result = pixel.side_length
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assert result == 1_000
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def test_area(self, pixel):
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"""Test `Pixel.area` property."""
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result = pixel.area
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assert result == 1.0
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