urban-meal-delivery/tests/db/test_grids.py
Alexander Hess 605ade4078
Add Pixel.northeast/southwest properties
- the properties are needed for the drawing functionalitites
2021-01-26 17:05:36 +01:00

239 lines
8.8 KiB
Python

"""Test the ORM's `Grid` model."""
import pytest
import sqlalchemy as sqla
from sqlalchemy import exc as sa_exc
from urban_meal_delivery import db
class TestSpecialMethods:
"""Test special methods in `Grid`."""
def test_create_grid(self, grid):
"""Test instantiation of a new `Grid` object."""
assert grid is not None
def test_text_representation(self, grid):
"""`Grid` has a non-literal text representation."""
result = repr(grid)
assert result == f'<Grid: {grid.pixel_area} sqr. km>'
@pytest.mark.db
@pytest.mark.no_cover
class TestConstraints:
"""Test the database constraints defined in `Grid`."""
def test_insert_into_database(self, db_session, grid):
"""Insert an instance into the (empty) database."""
assert db_session.query(db.Grid).count() == 0
db_session.add(grid)
db_session.commit()
assert db_session.query(db.Grid).count() == 1
def test_delete_a_referenced_city(self, db_session, grid):
"""Remove a record that is referenced with a FK."""
db_session.add(grid)
db_session.commit()
# Must delete without ORM as otherwise an UPDATE statement is emitted.
stmt = sqla.delete(db.City).where(db.City.id == grid.city.id)
with pytest.raises(
sa_exc.IntegrityError, match='fk_grids_to_cities_via_city_id',
):
db_session.execute(stmt)
def test_two_grids_with_identical_side_length(self, db_session, grid):
"""Insert a record that violates a unique constraint."""
db_session.add(grid)
db_session.commit()
# Create a `Grid` with the same `.side_length` in the same `.city`.
another_grid = db.Grid(city=grid.city, side_length=grid.side_length)
db_session.add(another_grid)
with pytest.raises(sa_exc.IntegrityError, match='duplicate key value'):
db_session.commit()
class TestProperties:
"""Test properties in `Grid`."""
def test_pixel_area(self, grid):
"""Test `Grid.pixel_area` property."""
result = grid.pixel_area
assert result == 1.0
class TestGridification:
"""Test the `Grid.gridify()` constructor."""
@pytest.fixture
def addresses_mock(self, mocker, monkeypatch):
"""A `Mock` whose `.return_value` are to be set ...
... to the addresses that are gridified. The addresses are
all considered `Order.pickup_address` attributes for some orders.
"""
mock = mocker.Mock()
query = ( # noqa:ECE001
mock.query.return_value.join.return_value.filter.return_value.all # noqa:E501,WPS219
)
monkeypatch.setattr(db, 'session', mock)
return query
@pytest.mark.no_cover
def test_no_pixel_without_addresses(self, city, addresses_mock):
"""Without orders, there are no `Pixel` objects on the `grid`.
This test case skips the `for`-loop inside `Grid.gridify()`.
"""
addresses_mock.return_value = []
# The chosen `side_length` would result in one `Pixel` if there were orders.
# `+1` as otherwise there would be a second pixel in one direction.
side_length = max(city.total_x, city.total_y) + 1
result = db.Grid.gridify(city=city, side_length=side_length)
assert isinstance(result, db.Grid)
assert len(result.pixels) == 0 # noqa:WPS507
def test_one_pixel_with_one_address(self, city, order, addresses_mock):
"""At the very least, there must be one `Pixel` ...
... if the `side_length` is greater than both the
horizontal and vertical distances of the viewport.
"""
addresses_mock.return_value = [order.pickup_address]
# `+1` as otherwise there would be a second pixel in one direction.
side_length = max(city.total_x, city.total_y) + 1
result = db.Grid.gridify(city=city, side_length=side_length)
assert isinstance(result, db.Grid)
assert len(result.pixels) == 1
def test_one_pixel_with_two_addresses(self, city, make_order, addresses_mock):
"""At the very least, there must be one `Pixel` ...
... if the `side_length` is greater than both the
horizontal and vertical distances of the viewport.
This test case is necessary as `test_one_pixel_with_one_address`
does not have to re-use an already created `Pixel` object internally.
"""
orders = [make_order(), make_order()]
addresses_mock.return_value = [order.pickup_address for order in orders]
# `+1` as otherwise there would be a second pixel in one direction.
side_length = max(city.total_x, city.total_y) + 1
result = db.Grid.gridify(city=city, side_length=side_length)
assert isinstance(result, db.Grid)
assert len(result.pixels) == 1
def test_no_pixel_with_one_address_too_far_south(self, city, order, addresses_mock):
"""An `address` outside the `city`'s viewport is discarded."""
# Move the `address` just below `city.southwest`.
order.pickup_address.latitude = city.southwest.latitude - 0.1
addresses_mock.return_value = [order.pickup_address]
# `+1` as otherwise there would be a second pixel in one direction.
side_length = max(city.total_x, city.total_y) + 1
result = db.Grid.gridify(city=city, side_length=side_length)
assert isinstance(result, db.Grid)
assert len(result.pixels) == 0 # noqa:WPS507
@pytest.mark.no_cover
def test_no_pixel_with_one_address_too_far_west(self, city, order, addresses_mock):
"""An `address` outside the `city`'s viewport is discarded.
This test is a logical sibling to
`test_no_pixel_with_one_address_too_far_south` and therefore redundant.
"""
# Move the `address` just left to `city.southwest`.
order.pickup_address.longitude = city.southwest.longitude - 0.1
addresses_mock.return_value = [order.pickup_address]
# `+1` as otherwise there would be a second pixel in one direction.
side_length = max(city.total_x, city.total_y) + 1
result = db.Grid.gridify(city=city, side_length=side_length)
assert isinstance(result, db.Grid)
assert len(result.pixels) == 0 # noqa:WPS507
@pytest.mark.no_cover
def test_two_pixels_with_two_addresses(self, city, make_address, addresses_mock):
"""Two `Address` objects in distinct `Pixel` objects.
This test is more of a sanity check.
"""
# Create two `Address` objects in distinct `Pixel`s.
addresses_mock.return_value = [
# One `Address` in the lower-left `Pixel`, ...
make_address(latitude=48.8357377, longitude=2.2517412),
# ... and another one in the upper-right one.
make_address(latitude=48.8898312, longitude=2.4357622),
]
side_length = max(city.total_x // 2, city.total_y // 2) + 1
# By assumption of the test data.
n_pixels_x = (city.total_x // side_length) + 1
n_pixels_y = (city.total_y // side_length) + 1
assert n_pixels_x * n_pixels_y == 4
# Create a `Grid` with at most four `Pixel`s.
result = db.Grid.gridify(city=city, side_length=side_length)
assert isinstance(result, db.Grid)
assert len(result.pixels) == 2
@pytest.mark.db
@pytest.mark.no_cover
@pytest.mark.parametrize('side_length', [250, 500, 1_000, 2_000, 4_000, 8_000])
def test_make_random_grids( # noqa:WPS211,WPS218
self, db_session, city, make_address, make_restaurant, make_order, side_length,
):
"""With 100 random `Address` objects, a grid must have ...
... between 1 and a deterministic upper bound of `Pixel` objects.
This test creates confidence that the created `Grid`
objects adhere to the database constraints.
"""
addresses = [make_address() for _ in range(100)]
restaurants = [make_restaurant(address=address) for address in addresses]
orders = [make_order(restaurant=restaurant) for restaurant in restaurants]
db_session.add_all(orders)
n_pixels_x = (city.total_x // side_length) + 1
n_pixels_y = (city.total_y // side_length) + 1
result = db.Grid.gridify(city=city, side_length=side_length)
assert isinstance(result, db.Grid)
assert 1 <= len(result.pixels) <= n_pixels_x * n_pixels_y
# Sanity checks for `Pixel.southwest` and `Pixel.northeast`.
for pixel in result.pixels:
assert abs(pixel.southwest.x - pixel.n_x * side_length) < 2
assert abs(pixel.southwest.y - pixel.n_y * side_length) < 2
assert abs(pixel.northeast.x - (pixel.n_x + 1) * side_length) < 2
assert abs(pixel.northeast.y - (pixel.n_y + 1) * side_length) < 2
db_session.add(result)
db_session.commit()