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# This file is part of Hypothesis, which may be found at
# https://github.com/HypothesisWorks/hypothesis/
#
# Copyright the Hypothesis Authors.
# Individual contributors are listed in AUTHORS.rst and the git log.
#
# This Source Code Form is subject to the terms of the Mozilla Public License,
# v. 2.0. If a copy of the MPL was not distributed with this file, You can
# obtain one at https://mozilla.org/MPL/2.0/.
import pytest
from hypothesis import given, strategies as st
from hypothesis.strategies import integers, lists
@pytest.mark.parametrize(
("specifier", "condition"),
[(integers(), lambda x: x > 1), (lists(integers()), bool)],
)
def test_filter_correctly(specifier, condition):
@given(specifier.filter(condition))
def test_is_filtered(x):
assert condition(x)
test_is_filtered()
# A variety of strategies that generate the integers 1-20 inclusive, but might
# differ in their support for special-case filtering.
one_to_twenty_strategies = [
st.integers(1, 20),
st.integers(0, 19).map(lambda x: x + 1),
st.sampled_from(range(1, 21)),
st.sampled_from(range(20)).map(lambda x: x + 1),
]
@pytest.mark.parametrize("base", one_to_twenty_strategies)
@given(
data=st.data(),
forbidden_values=st.lists(st.integers(1, 20), max_size=19, unique=True),
)
def test_chained_filters_agree(data, forbidden_values, base):
def forbid(s, forbidden):
"""Helper function to avoid Python variable scoping issues."""
return s.filter(lambda x: x != forbidden)
s = base
for forbidden in forbidden_values:
s = forbid(s, forbidden)
x = data.draw(s)
assert 1 <= x <= 20
assert x not in forbidden_values
@pytest.mark.parametrize("base", one_to_twenty_strategies)
def test_chained_filters_repr(base):
def foo(x):
return x != 0
def bar(x):
return x != 2
filtered = base.filter(foo)
chained = filtered.filter(bar)
assert repr(chained) == f"{base!r}.filter(foo).filter(bar)"
assert repr(filtered) == f"{base!r}.filter(foo)"
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