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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, note, settings, strategies as st
from hypothesis.errors import HypothesisWarning, InvalidArgument
from tests.common.debug import (
assert_all_examples,
assert_no_examples,
check_can_generate_examples,
find_any,
minimal,
)
from tests.common.utils import checks_deprecated_behaviour
@given(st.recursive(st.booleans(), st.lists, max_leaves=10))
def test_respects_leaf_limit(xs):
def flatten(x):
if isinstance(x, list):
return sum(map(flatten, x), [])
else:
return [x]
assert len(flatten(xs)) <= 10
def test_can_find_nested():
x = minimal(
st.recursive(st.booleans(), lambda x: st.tuples(x, x)),
lambda x: isinstance(x, tuple) and isinstance(x[0], tuple),
)
assert x == ((False, False), False)
def test_recursive_call_validates_expand_returns_strategies():
with pytest.raises(InvalidArgument):
check_can_generate_examples(st.recursive(st.booleans(), lambda x: 1))
def test_recursive_call_validates_base_is_strategy():
x = st.recursive(1, lambda x: st.none())
with pytest.raises(InvalidArgument):
check_can_generate_examples(x)
def test_can_find_exactly_max_leaves():
strat = st.recursive(st.none(), lambda x: st.tuples(x, x), max_leaves=5)
def enough_leaves(t):
print(t)
count = 0
stack = [t]
while stack:
s = stack.pop()
if s is None:
count += 1
else:
stack.extend(s)
return count >= 5
find_any(strat, enough_leaves)
@given(st.recursive(st.none(), lambda x: st.tuples(x, x), max_leaves=1))
def test_can_exclude_branching_with_max_leaves(t):
assert t is None
@given(st.recursive(st.none(), lambda x: st.one_of(x, x)))
def test_issue_1502_regression(s):
pass
def test_recursive_can_generate_varied_structures():
values = st.recursive(st.none(), st.lists)
find_any(values, lambda x: x is None)
find_any(values, lambda x: isinstance(x, list))
find_any(
values, lambda x: isinstance(x, list) and any(isinstance(y, list) for y in x)
)
@checks_deprecated_behaviour
def test_recursive_can_generate_varied_structures_without_using_leaves():
values = st.recursive(st.none(), lambda _: st.lists(st.none()))
find_any(values, lambda x: x is None)
find_any(values, lambda x: isinstance(x, list))
# The bad `extend` function means we can't actually recurse!
assert_no_examples(
values, lambda x: isinstance(x, list) and any(isinstance(y, list) for y in x)
)
@pytest.mark.parametrize(
"s",
[
st.recursive(None, st.lists),
st.recursive(st.none(), lambda x: None),
st.recursive(st.none(), st.lists, max_leaves=-1),
st.recursive(st.none(), st.lists, max_leaves=0),
st.recursive(st.none(), st.lists, max_leaves=1.0),
st.recursive(st.none(), st.lists, min_leaves=-1),
st.recursive(st.none(), st.lists, min_leaves=0),
st.recursive(st.none(), st.lists, min_leaves=1.0),
st.recursive(st.none(), st.lists, min_leaves=10, max_leaves=5),
st.recursive(st.none(), lambda _: st.lists(st.none()), min_leaves=1),
],
)
def test_invalid_args(s):
with pytest.raises(InvalidArgument):
check_can_generate_examples(s)
def _count_leaves(tree):
if isinstance(tree, tuple):
return sum(_count_leaves(child) for child in tree)
return 1
@given(st.data())
@settings(max_examples=5, suppress_health_check=["filter_too_much"])
def test_respects_min_leaves(data):
min_leaves = data.draw(st.integers(1, 20))
max_leaves = data.draw(st.integers(min_leaves, 40))
note(f"{min_leaves=}")
note(f"{max_leaves=}")
s = st.recursive(
st.none(),
lambda x: st.tuples(x, x),
min_leaves=min_leaves,
max_leaves=max_leaves,
)
assert_all_examples(s, lambda tree: min_leaves <= _count_leaves(tree) <= max_leaves)
@given(st.recursive(st.none(), lambda x: st.tuples(x, x), min_leaves=5, max_leaves=5))
@settings(suppress_health_check=["filter_too_much"])
def test_can_set_exact_leaf_count(tree):
assert _count_leaves(tree) == 5
def test_identity_extend_warns():
with pytest.warns(HypothesisWarning, match="extend=lambda x: x is a no-op"):
st.recursive(st.none(), lambda x: x).validate()
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