+++ /dev/null
-"""Property-based tests 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 re
-
-import hypothesmith
-from hypothesis import HealthCheck, given, settings
-from hypothesis import strategies as st
-
-import black
-from blib2to3.pgen2.tokenize import TokenError
-
-
-# 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
- derandomize=True, # deterministic mode to avoid CI flakiness
- deadline=None, # ignore Hypothesis' health checks; we already know that
- suppress_health_check=list(HealthCheck), # 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(),
- # Using randomly-varied modes helps us to exercise less common code paths.
- mode=st.builds(
- black.FileMode,
- line_length=st.just(88) | st.integers(0, 200),
- string_normalization=st.booleans(),
- preview=st.booleans(),
- is_pyi=st.booleans(),
- magic_trailing_comma=st.booleans(),
- ),
-)
-def test_idempotent_any_syntatically_valid_python(
- src_contents: str, mode: black.FileMode
-) -> None:
- # Before starting, let's confirm that the input string is valid Python:
- compile(src_contents, "<string>", "exec") # else the bug is in hypothesmith
-
- # Then format the code...
- try:
- dst_contents = black.format_str(src_contents, mode=mode)
- except black.InvalidInput:
- # This is a bug - if it's valid Python code, as above, Black should be
- # able to cope with it. See issues #970, #1012
- # TODO: remove this try-except block when issues are resolved.
- return
- except TokenError as e:
- if ( # Special-case logic for backslashes followed by newlines or end-of-input
- e.args[0] == "EOF in multi-line statement"
- and re.search(r"\\($|\r?\n)", src_contents) is not None
- ):
- # This is a bug - if it's valid Python code, as above, Black should be
- # able to cope with it. See issue #1012.
- # TODO: remove this block when the issue is resolved.
- return
- raise
-
- # And check that we got equivalent and stable output.
- black.assert_equivalent(src_contents, dst_contents)
- black.assert_stable(src_contents, dst_contents, mode=mode)
-
- # Future test: check that pure-python and mypyc versions of black
- # give identical output for identical input?
-
-
-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 # type: ignore[import]
- except ImportError:
- pass
- else:
- test = test_idempotent_any_syntatically_valid_python
- atheris.Setup(
- sys.argv,
- test.hypothesis.fuzz_one_input, # type: ignore[attr-defined]
- )
- atheris.Fuzz()