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Tests on Django Q object assertion helper
# encoding: utf-8
import pytest
from django.db.models import Q
def assert_q_equal(left, right):
"""
Simply test two Q objects for equality. Does is not match commutative.
Args:
left (Q)
right (Q)
Raises:
AssertionError: When -
* `left` or `right` are not an instance of `Q`
* `left` and `right` are not considered equal.
"""
assert isinstance(left, Q), f'{left.__class__} is not subclass of Q'
assert isinstance(right, Q), f'{right.__class__} is not subclass of Q'
assert str(left) == str(right), f'Q{left} != Q{right}'
# --- Matches ---
def test_eq_self():
"""
Matching is reflexive, matches self
"""
q_a = Q(location='London')
assert_q_equal(q_a, q_a)
def test_eq():
"""
Matching Q objects matches their internal
"""
assert_q_equal(Q(location='北京市'), Q(location='北京市'))
def test_eq_multi_and():
"""
assert_q_equal matches multi Qs
"""
assert_q_equal(Q(direction='north') & Q(speed=12), Q(direction='north') & Q(speed=12))
assert_q_equal(Q(direction='north') | Q(speed=12), Q(direction='north') | Q(speed=12))
# Non-matches
def test_neq_simple():
"""
assert_q_equal spots that Q filters do not match
"""
q_a = Q(location='北京市')
q_b = Q(location='北京')
with pytest.raises(AssertionError):
assert_q_equal(q_a, q_b)
def test_neq_multi_and():
"""
assert_q_equal matches multi Qs
"""
q_a = Q(direction='north') & Q(speed=13)
q_b = Q(direction='north') & Q(speed=12)
with pytest.raises(AssertionError):
assert_q_equal(q_a, q_b)
def test_neq_multi_not_commutative():
"""
assert_q_equal does not match commutative: A & B != B & A
"""
q_a = Q(speed=12) & Q(direction='north')
q_b = Q(direction='north') & Q(speed=12)
with pytest.raises(AssertionError):
assert_q_equal(q_a, q_b)
def test_neq_type_a():
"""
assert_q_equal raises if either q is not of type Q, left side
"""
q_a = 1
q_b = Q(location='New York')
with pytest.raises(AssertionError):
assert_q_equal(q_a, q_b)
def test_neq_type_b():
"""
assert_q_equal raises if either q is not of type Q, right side
"""
q_a = Q(location='New York')
q_b = "(AND: ('location', u'New York'))"
with pytest.raises(AssertionError):
assert_q_equal(q_a, q_b)
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