/
test_engine.py
1594 lines (1182 loc) · 41.3 KB
/
test_engine.py
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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 re
import time
from random import Random
from unittest.mock import Mock
import pytest
from hypothesis import HealthCheck, Phase, Verbosity, settings
from hypothesis.database import ExampleDatabase, InMemoryExampleDatabase
from hypothesis.errors import FailedHealthCheck, Flaky
from hypothesis.internal.compat import int_from_bytes
from hypothesis.internal.conjecture import engine as engine_module
from hypothesis.internal.conjecture.data import ConjectureData, Overrun, Status
from hypothesis.internal.conjecture.engine import (
MIN_TEST_CALLS,
ConjectureRunner,
ExitReason,
RunIsComplete,
)
from hypothesis.internal.conjecture.pareto import DominanceRelation, dominance
from hypothesis.internal.conjecture.shrinker import Shrinker, block_program
from hypothesis.internal.conjecture.utils import integer_range
from hypothesis.internal.entropy import deterministic_PRNG
from tests.common.strategies import SLOW, HardToShrink
from tests.common.utils import no_shrink
from tests.conjecture.common import (
SOME_LABEL,
TEST_SETTINGS,
buffer_size_limit,
run_to_buffer,
run_to_data,
shrinking_from,
)
def test_can_index_results():
@run_to_buffer
def f(data):
data.draw_bytes(5)
data.mark_interesting()
assert f.index(0) == 0
assert f.count(0) == 5
def test_non_cloneable_intervals():
@run_to_buffer
def x(data):
data.draw_bytes(10)
data.draw_bytes(9)
data.mark_interesting()
assert x == bytes(19)
def test_deletable_draws():
@run_to_buffer
def x(data):
while True:
x = data.draw_bytes(2)
if x[0] == 255:
data.mark_interesting()
assert x == bytes([255, 0])
def zero_dist(random, n):
return bytes(n)
def test_can_load_data_from_a_corpus():
key = b"hi there"
db = ExampleDatabase()
value = b"=\xc3\xe4l\x81\xe1\xc2H\xc9\xfb\x1a\xb6bM\xa8\x7f"
db.save(key, value)
def f(data):
if data.draw_bytes(len(value)) == value:
data.mark_interesting()
runner = ConjectureRunner(f, settings=settings(database=db), database_key=key)
runner.run()
(last_data,) = runner.interesting_examples.values()
assert last_data.buffer == value
assert len(list(db.fetch(key))) == 1
def slow_shrinker():
strat = HardToShrink()
def accept(data):
if data.draw(strat):
data.mark_interesting()
return accept
@pytest.mark.parametrize("n", [1, 5])
def test_terminates_shrinks(n, monkeypatch):
db = InMemoryExampleDatabase()
def generate_new_examples(self):
self.cached_test_function([255] * 1000)
monkeypatch.setattr(
ConjectureRunner, "generate_new_examples", generate_new_examples
)
monkeypatch.setattr(engine_module, "MAX_SHRINKS", n)
runner = ConjectureRunner(
slow_shrinker(),
settings=settings(max_examples=5000, database=db),
random=Random(0),
database_key=b"key",
)
runner.run()
(last_data,) = runner.interesting_examples.values()
assert last_data.status == Status.INTERESTING
assert runner.shrinks == n
in_db = set(db.data[runner.secondary_key])
assert len(in_db) == n
def test_detects_flakiness():
failed_once = [False]
count = [0]
def tf(data):
data.draw_bytes(1)
count[0] += 1
if not failed_once[0]:
failed_once[0] = True
data.mark_interesting()
runner = ConjectureRunner(tf)
runner.run()
assert runner.exit_reason == ExitReason.flaky
assert count == [MIN_TEST_CALLS + 1]
def recur(i, data):
if i >= 1:
recur(i - 1, data)
def test_recursion_error_is_not_flaky():
def tf(data):
i = data.draw_bits(16)
try:
recur(i, data)
except RecursionError:
data.mark_interesting()
runner = ConjectureRunner(tf)
runner.run()
assert runner.exit_reason == ExitReason.finished
def test_variadic_draw():
def draw_list(data):
result = []
while True:
data.start_example(SOME_LABEL)
d = data.draw_bytes(1)[0] & 7
if d:
result.append(data.draw_bytes(d))
data.stop_example()
if not d:
break
return result
@run_to_buffer
def b(data):
if any(all(d) for d in draw_list(data)):
data.mark_interesting()
ls = draw_list(ConjectureData.for_buffer(b))
assert len(ls) == 1
assert len(ls[0]) == 1
def test_draw_to_overrun():
@run_to_buffer
def x(data):
d = (data.draw_bytes(1)[0] - 8) & 0xFF
data.draw_bytes(128 * d)
if d >= 2:
data.mark_interesting()
assert x == bytes([10]) + bytes(128 * 2)
def test_can_navigate_to_a_valid_example():
def f(data):
i = int_from_bytes(data.draw_bytes(2))
data.draw_bytes(i)
data.mark_interesting()
runner = ConjectureRunner(f, settings=settings(max_examples=5000, database=None))
with buffer_size_limit(2):
runner.run()
assert runner.interesting_examples
def test_stops_after_max_examples_when_reading():
key = b"key"
db = ExampleDatabase(":memory:")
for i in range(10):
db.save(key, bytes([i]))
seen = []
def f(data):
seen.append(data.draw_bytes(1))
runner = ConjectureRunner(
f, settings=settings(max_examples=1, database=db), database_key=key
)
runner.run()
assert len(seen) == 1
def test_stops_after_max_examples_when_generating():
seen = []
def f(data):
seen.append(data.draw_bytes(1))
runner = ConjectureRunner(f, settings=settings(max_examples=1, database=None))
runner.run()
assert len(seen) == 1
@pytest.mark.parametrize("examples", [1, 5, 20, 50])
def test_stops_after_max_examples_when_generating_more_bugs(examples):
seen = []
bad = [False, False]
def f(data):
seen.append(data.draw_bits(32))
# Rare, potentially multi-error conditions
if seen[-1] > 2**31:
bad[0] = True
raise ValueError
bad[1] = True
raise Exception
runner = ConjectureRunner(
f, settings=settings(max_examples=examples, phases=[Phase.generate])
)
try:
runner.run()
except Exception:
pass
# No matter what, whether examples is larger or smalller than MAX_TEST_CALLS,
# we stop looking at max_examples. (and re-run each failure for the traceback)
assert len(seen) <= examples + sum(bad)
def test_interleaving_engines():
children = []
@run_to_buffer
def x(data):
rnd = Random(data.draw_bytes(1))
def g(d2):
d2.draw_bytes(1)
data.mark_interesting()
runner = ConjectureRunner(g, random=rnd)
children.append(runner)
runner.run()
if runner.interesting_examples:
data.mark_interesting()
assert x == b"\0"
for c in children:
assert not c.interesting_examples
def test_phases_can_disable_shrinking():
seen = set()
def f(data):
seen.add(bytes(data.draw_bytes(32)))
data.mark_interesting()
runner = ConjectureRunner(
f, settings=settings(database=None, phases=(Phase.reuse, Phase.generate))
)
runner.run()
assert len(seen) == 1
def test_reuse_phase_runs_for_max_examples_if_generation_is_disabled():
with deterministic_PRNG():
db = InMemoryExampleDatabase()
for i in range(256):
db.save(b"key", bytes([i]))
seen = set()
def test(data):
seen.add(data.draw_bits(8))
ConjectureRunner(
test,
settings=settings(max_examples=100, database=db, phases=[Phase.reuse]),
database_key=b"key",
).run()
assert len(seen) == 100
def test_erratic_draws():
n = [0]
with pytest.raises(Flaky):
@run_to_buffer
def x(data):
data.draw_bytes(n[0])
data.draw_bytes(255 - n[0])
if n[0] == 255:
data.mark_interesting()
else:
n[0] += 1
def test_no_read_no_shrink():
count = [0]
@run_to_buffer
def x(data):
count[0] += 1
data.mark_interesting()
assert x == b""
assert count == [1]
def test_one_dead_branch():
with deterministic_PRNG():
seen = set()
@run_to_buffer
def x(data):
i = data.draw_bytes(1)[0]
if i > 0:
data.mark_invalid()
i = data.draw_bytes(1)[0]
if len(seen) < 255:
seen.add(i)
elif i not in seen:
data.mark_interesting()
def test_does_not_save_on_interrupt():
def interrupts(data):
raise KeyboardInterrupt()
db = InMemoryExampleDatabase()
runner = ConjectureRunner(
interrupts, settings=settings(database=db), database_key=b"key"
)
with pytest.raises(KeyboardInterrupt):
runner.run()
assert not db.data
def test_returns_written():
value = b"\0\1\2\3"
@run_to_buffer
def written(data):
data.write(value)
data.mark_interesting()
assert value == written
def fails_health_check(label, **kwargs):
def accept(f):
runner = ConjectureRunner(
f,
settings=settings(
max_examples=100, phases=no_shrink, database=None, **kwargs
),
)
with pytest.raises(FailedHealthCheck) as e:
runner.run()
assert e.value.health_check == label
assert not runner.interesting_examples
return accept
def test_fails_health_check_for_all_invalid():
@fails_health_check(HealthCheck.filter_too_much)
def _(data):
data.draw_bytes(2)
data.mark_invalid()
def test_fails_health_check_for_large_base():
@fails_health_check(HealthCheck.large_base_example)
def _(data):
data.draw_bytes(10**6)
def test_fails_health_check_for_large_non_base():
@fails_health_check(HealthCheck.data_too_large)
def _(data):
if data.draw_bits(8):
data.draw_bytes(10**6)
def test_fails_health_check_for_slow_draws():
@fails_health_check(HealthCheck.too_slow)
def _(data):
data.draw(SLOW)
@pytest.mark.parametrize("n_large", [1, 5, 8, 15])
def test_can_shrink_variable_draws(n_large):
target = 128 * n_large
@run_to_data
def data(data):
n = data.draw_bits(4)
b = [data.draw_bits(8) for _ in range(n)]
if sum(b) >= target:
data.mark_interesting()
x = data.buffer
assert x.count(0) == 0
assert sum(x[1:]) == target
def test_run_nothing():
def f(data):
raise AssertionError
runner = ConjectureRunner(f, settings=settings(phases=()))
runner.run()
assert runner.call_count == 0
class Foo:
def __repr__(self):
return "stuff"
def test_debug_data(capsys):
buf = [0, 1, 2]
def f(data):
for x in bytes(buf):
if data.draw_bits(8) != x:
data.mark_invalid()
data.start_example(1)
data.stop_example()
data.mark_interesting()
runner = ConjectureRunner(
f,
settings=settings(
max_examples=5000,
database=None,
suppress_health_check=HealthCheck.all(),
verbosity=Verbosity.debug,
),
)
runner.cached_test_function(buf)
runner.run()
out, _ = capsys.readouterr()
assert re.match("\\d+ bytes \\[.*\\] -> ", out)
assert "INTERESTING" in out
def test_can_write_bytes_towards_the_end():
buf = b"\1\2\3"
def f(data):
if data.draw_bits(1):
data.draw_bytes(5)
data.write(bytes(buf))
assert bytes(data.buffer[-len(buf) :]) == buf
with buffer_size_limit(10):
ConjectureRunner(f).run()
def test_uniqueness_is_preserved_when_writing_at_beginning():
seen = set()
def f(data):
data.write(bytes(1))
n = data.draw_bits(3)
assert n not in seen
seen.add(n)
runner = ConjectureRunner(f, settings=settings(max_examples=50))
runner.run()
assert runner.valid_examples == len(seen)
@pytest.mark.parametrize("skip_target", [False, True])
@pytest.mark.parametrize("initial_attempt", [127, 128])
def test_clears_out_its_database_on_shrinking(
initial_attempt, skip_target, monkeypatch
):
def generate_new_examples(self):
self.cached_test_function(initial_attempt)
monkeypatch.setattr(
ConjectureRunner, "generate_new_examples", generate_new_examples
)
key = b"key"
db = InMemoryExampleDatabase()
def f(data):
if data.draw_bits(8) >= 127:
data.mark_interesting()
runner = ConjectureRunner(
f,
settings=settings(database=db, max_examples=256),
database_key=key,
random=Random(0),
)
for n in range(256):
if n != 127 or not skip_target:
db.save(runner.secondary_key, bytes([n]))
runner.run()
assert len(runner.interesting_examples) == 1
for b in db.fetch(runner.secondary_key):
assert b[0] >= 127
assert len(list(db.fetch(runner.database_key))) == 1
def test_detects_too_small_block_starts():
call_count = [0]
def f(data):
assert call_count[0] == 0
call_count[0] += 1
data.draw_bytes(8)
data.mark_interesting()
runner = ConjectureRunner(f, settings=settings(database=None))
r = runner.cached_test_function(bytes(8))
assert r.status == Status.INTERESTING
assert call_count[0] == 1
r2 = runner.cached_test_function(bytes([255] * 7))
assert r2.status == Status.OVERRUN
assert call_count[0] == 1
def test_shrinks_both_interesting_examples(monkeypatch):
def generate_new_examples(self):
self.cached_test_function(bytes([1]))
monkeypatch.setattr(
ConjectureRunner, "generate_new_examples", generate_new_examples
)
def f(data):
n = data.draw_bits(8)
data.mark_interesting(n & 1)
runner = ConjectureRunner(f, database_key=b"key")
runner.run()
assert runner.interesting_examples[0].buffer == bytes([0])
assert runner.interesting_examples[1].buffer == bytes([1])
def test_discarding(monkeypatch):
monkeypatch.setattr(Shrinker, "shrink", Shrinker.remove_discarded)
monkeypatch.setattr(
ConjectureRunner,
"generate_new_examples",
lambda runner: runner.cached_test_function(bytes([0, 1] * 10)),
)
@run_to_buffer
def x(data):
count = 0
while count < 10:
data.start_example(SOME_LABEL)
b = data.draw_bits(1)
if b:
count += 1
data.stop_example(discard=not b)
data.mark_interesting()
assert x == bytes(bytes([1]) * 10)
def test_can_remove_discarded_data():
@shrinking_from(bytes([0] * 10 + [11]))
def shrinker(data):
while True:
data.start_example(SOME_LABEL)
b = data.draw_bits(8)
data.stop_example(discard=(b == 0))
if b == 11:
break
data.mark_interesting()
shrinker.remove_discarded()
assert list(shrinker.buffer) == [11]
def test_discarding_iterates_to_fixed_point():
@shrinking_from(bytes(list(range(100, -1, -1))))
def shrinker(data):
data.start_example(0)
data.draw_bits(8)
data.stop_example(discard=True)
while data.draw_bits(8):
pass
data.mark_interesting()
shrinker.remove_discarded()
assert list(shrinker.buffer) == [1, 0]
def test_discarding_is_not_fooled_by_empty_discards():
@shrinking_from(bytes([1, 1]))
def shrinker(data):
data.draw_bits(1)
data.start_example(0)
data.stop_example(discard=True)
data.draw_bits(1)
data.mark_interesting()
shrinker.remove_discarded()
assert shrinker.shrink_target.has_discards
def test_discarding_can_fail(monkeypatch):
@shrinking_from(bytes([1]))
def shrinker(data):
data.start_example(0)
data.draw_bits(1)
data.stop_example(discard=True)
data.mark_interesting()
shrinker.remove_discarded()
assert any(e.discarded and e.length > 0 for e in shrinker.shrink_target.examples)
def test_shrinking_from_mostly_zero(monkeypatch):
monkeypatch.setattr(
ConjectureRunner,
"generate_new_examples",
lambda self: self.cached_test_function(bytes(5) + bytes([2])),
)
@run_to_buffer
def x(data):
s = [data.draw_bits(8) for _ in range(6)]
if any(s):
data.mark_interesting()
assert x == bytes(5) + bytes([1])
def test_handles_nesting_of_discard_correctly(monkeypatch):
monkeypatch.setattr(Shrinker, "shrink", Shrinker.remove_discarded)
monkeypatch.setattr(
ConjectureRunner,
"generate_new_examples",
lambda runner: runner.cached_test_function(bytes([0, 0, 1, 1])),
)
@run_to_buffer
def x(data):
while True:
data.start_example(SOME_LABEL)
succeeded = data.draw_bits(1)
data.start_example(SOME_LABEL)
data.draw_bits(1)
data.stop_example(discard=not succeeded)
data.stop_example(discard=not succeeded)
if succeeded:
data.mark_interesting()
assert x == bytes([1, 1])
def test_database_clears_secondary_key():
key = b"key"
database = InMemoryExampleDatabase()
def f(data):
if data.draw_bits(8) == 10:
data.mark_interesting()
else:
data.mark_invalid()
runner = ConjectureRunner(
f,
settings=settings(
max_examples=1, database=database, suppress_health_check=HealthCheck.all()
),
database_key=key,
)
for i in range(10):
database.save(runner.secondary_key, bytes([i]))
runner.cached_test_function([10])
assert runner.interesting_examples
assert len(set(database.fetch(key))) == 1
assert len(set(database.fetch(runner.secondary_key))) == 10
runner.clear_secondary_key()
assert len(set(database.fetch(key))) == 1
assert len(set(database.fetch(runner.secondary_key))) == 0
def test_database_uses_values_from_secondary_key():
key = b"key"
database = InMemoryExampleDatabase()
def f(data):
if data.draw_bits(8) >= 5:
data.mark_interesting()
else:
data.mark_invalid()
runner = ConjectureRunner(
f,
settings=settings(
max_examples=1, database=database, suppress_health_check=HealthCheck.all()
),
database_key=key,
)
for i in range(10):
database.save(runner.secondary_key, bytes([i]))
runner.cached_test_function([10])
assert runner.interesting_examples
assert len(set(database.fetch(key))) == 1
assert len(set(database.fetch(runner.secondary_key))) == 10
runner.clear_secondary_key()
assert len(set(database.fetch(key))) == 1
assert set(map(int_from_bytes, database.fetch(runner.secondary_key))) == set(
range(6, 11)
)
(v,) = runner.interesting_examples.values()
assert list(v.buffer) == [5]
def test_exit_because_max_iterations():
def f(data):
data.draw_bits(64)
data.mark_invalid()
runner = ConjectureRunner(
f,
settings=settings(
max_examples=1, database=None, suppress_health_check=HealthCheck.all()
),
)
runner.run()
assert runner.call_count <= 1000
assert runner.exit_reason == ExitReason.max_iterations
def test_exit_because_shrink_phase_timeout(monkeypatch):
val = [0]
def fast_time():
val[0] += 1000
return val[0]
def f(data):
if data.draw_bits(64) > 2**33:
data.mark_interesting()
monkeypatch.setattr(time, "perf_counter", fast_time)
runner = ConjectureRunner(f, settings=settings(database=None))
runner.run()
assert runner.exit_reason == ExitReason.very_slow_shrinking
assert runner.statistics["stopped-because"] == "shrinking was very slow"
def test_dependent_block_pairs_can_lower_to_zero():
@shrinking_from([1, 0, 1])
def shrinker(data):
if data.draw_bits(1):
n = data.draw_bits(16)
else:
n = data.draw_bits(8)
if n == 1:
data.mark_interesting()
shrinker.fixate_shrink_passes(["minimize_individual_blocks"])
assert list(shrinker.shrink_target.buffer) == [0, 1]
def test_handle_size_too_large_during_dependent_lowering():
@shrinking_from([1, 255, 0])
def shrinker(data):
if data.draw_bits(1):
data.draw_bits(16)
data.mark_interesting()
else:
data.draw_bits(8)
shrinker.fixate_shrink_passes(["minimize_individual_blocks"])
def test_block_may_grow_during_lexical_shrinking():
initial = bytes([2, 1, 1])
@shrinking_from(initial)
def shrinker(data):
n = data.draw_bits(8)
if n == 2:
data.draw_bits(8)
data.draw_bits(8)
else:
data.draw_bits(16)
data.mark_interesting()
shrinker.fixate_shrink_passes(["minimize_individual_blocks"])
assert list(shrinker.shrink_target.buffer) == [0, 0, 0]
def test_lower_common_block_offset_does_nothing_when_changed_blocks_are_zero():
@shrinking_from([1, 0, 1, 0])
def shrinker(data):
data.draw_bits(1)
data.draw_bits(1)
data.draw_bits(1)
data.draw_bits(1)
data.mark_interesting()
shrinker.mark_changed(1)
shrinker.mark_changed(3)
shrinker.lower_common_block_offset()
assert list(shrinker.shrink_target.buffer) == [1, 0, 1, 0]
def test_lower_common_block_offset_ignores_zeros():
@shrinking_from([2, 2, 0])
def shrinker(data):
n = data.draw_bits(8)
data.draw_bits(8)
data.draw_bits(8)
if n > 0:
data.mark_interesting()
for i in range(3):
shrinker.mark_changed(i)
shrinker.lower_common_block_offset()
assert list(shrinker.shrink_target.buffer) == [1, 1, 0]
def test_pandas_hack():
@shrinking_from([2, 1, 1, 7])
def shrinker(data):
n = data.draw_bits(8)
m = data.draw_bits(8)
if n == 1:
if m == 7:
data.mark_interesting()
data.draw_bits(8)
if data.draw_bits(8) == 7:
data.mark_interesting()
shrinker.fixate_shrink_passes([block_program("-XX")])
assert list(shrinker.shrink_target.buffer) == [1, 7]
def test_cached_test_function_returns_right_value():
count = [0]
def tf(data):
count[0] += 1
data.draw_bits(2)
data.mark_interesting()
with deterministic_PRNG():
runner = ConjectureRunner(tf, settings=TEST_SETTINGS)
for _ in range(2):
for b in (b"\0", b"\1"):
d = runner.cached_test_function(b)
assert d.status == Status.INTERESTING
assert d.buffer == b
assert count[0] == 2
def test_cached_test_function_does_not_reinvoke_on_prefix():
call_count = [0]
def test_function(data):
call_count[0] += 1
data.draw_bits(8)
data.write(bytes([7]))
data.draw_bits(8)
with deterministic_PRNG():
runner = ConjectureRunner(test_function, settings=TEST_SETTINGS)
data = runner.cached_test_function(bytes(3))
assert data.status == Status.VALID
for n in [2, 1, 0]:
prefix_data = runner.cached_test_function(bytes(n))
assert prefix_data is Overrun
assert call_count[0] == 1
def test_will_evict_entries_from_the_cache(monkeypatch):
monkeypatch.setattr(engine_module, "CACHE_SIZE", 5)
count = [0]
def tf(data):
data.draw_bytes(1)
count[0] += 1
runner = ConjectureRunner(tf, settings=TEST_SETTINGS)
for _ in range(3):
for n in range(10):
runner.cached_test_function([n])
# Because we exceeded the cache size, our previous
# calls will have been evicted, so each call to
# cached_test_function will have to reexecute.
assert count[0] == 30
def test_branch_ending_in_write():
seen = set()
def tf(data):
count = 0
while data.draw_bits(1):
count += 1
if count > 1:
data.draw_bits(1, forced=0)
b = bytes(data.buffer)
assert b not in seen
seen.add(b)
with deterministic_PRNG():
runner = ConjectureRunner(tf, settings=TEST_SETTINGS)
for _ in range(100):
prefix = runner.generate_novel_prefix()
attempt = prefix + bytes(2)
data = runner.cached_test_function(attempt)
assert data.status == Status.VALID
assert attempt.startswith(data.buffer)
def test_exhaust_space():
with deterministic_PRNG():
runner = ConjectureRunner(
lambda data: data.draw_bits(1), settings=TEST_SETTINGS
)
runner.run()
assert runner.tree.is_exhausted