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"""Property-based tests for ast_decompiler, based on those for Black.
By Zac Hatfield-Dodds, based on my Hypothesmith tool for source code
generation. You can run this file with `python`, `pytest`, or (soon)
a coverage-guided fuzzer I'm working on.
"""
import hypothesmith
from hypothesis import HealthCheck, given, settings
try:
import atheris
except ImportError:
from ast_decompiler.check import check
else:
with atheris.instrument_imports():
from ast_decompiler.check import check
# This test uses the Hypothesis and Hypothesmith libraries to generate random
# syntatically-valid Python source code and run Black in odd modes.
@settings(
max_examples=1000, # roughly 1k tests/minute, or half that under coverage
deadline=None, # ignore Hypothesis' health checks; we already know that
suppress_health_check=HealthCheck.all(), # this is slow and filter-heavy.
)
@given(
# Note that while Hypothesmith might generate code unlike that written by
# humans, it's a general test that should pass for any *valid* source code.
# (so e.g. running it against code scraped of the internet might also help)
src_contents=hypothesmith.from_grammar()
| hypothesmith.from_node()
)
def test_idempotent_any_syntatically_valid_python(src_contents: str) -> None:
# Before starting, let's confirm that the input string is valid Python:
compile(src_contents, "<string>", "exec") # else the bug is in hypothesmith
check(src_contents)
if __name__ == "__main__":
# Run tests, including shrinking and reporting any known failures.
test_idempotent_any_syntatically_valid_python()
# If Atheris is available, run coverage-guided fuzzing.
# (if you want only bounded fuzzing, just use `pytest fuzz.py`)
try:
import sys
import atheris
except ImportError:
pass
else:
test = test_idempotent_any_syntatically_valid_python
atheris.Setup(sys.argv, test.hypothesis.fuzz_one_input)
atheris.Fuzz()
|
