All patches and comments are welcome. Please squash your changes to logical
commits before using git-format-patch and git-send-email to
patches@git.madduck.net.
If you'd read over the Git project's submission guidelines and adhered to them,
I'd be especially grateful.
1 """Property-based tests for Black.
3 By Zac Hatfield-Dodds, based on my Hypothesmith tool for source code
4 generation. You can run this file with `python`, `pytest`, or (soon)
5 a coverage-guided fuzzer I'm working on.
9 from hypothesis import HealthCheck, given, settings, strategies as st
14 # This test uses the Hypothesis and Hypothesmith libraries to generate random
15 # syntatically-valid Python source code and run Black in odd modes.
17 max_examples=1000, # roughly 1k tests/minute, or half that under coverage
18 derandomize=True, # deterministic mode to avoid CI flakiness
19 deadline=None, # ignore Hypothesis' health checks; we already know that
20 suppress_health_check=HealthCheck.all(), # this is slow and filter-heavy.
23 # Note that while Hypothesmith might generate code unlike that written by
24 # humans, it's a general test that should pass for any *valid* source code.
25 # (so e.g. running it against code scraped of the internet might also help)
26 src_contents=hypothesmith.from_grammar() | hypothesmith.from_node(),
27 # Using randomly-varied modes helps us to exercise less common code paths.
30 line_length=st.just(88) | st.integers(0, 200),
31 string_normalization=st.booleans(),
35 def test_idempotent_any_syntatically_valid_python(
36 src_contents: str, mode: black.FileMode
38 # Before starting, let's confirm that the input string is valid Python:
39 compile(src_contents, "<string>", "exec") # else the bug is in hypothesmith
41 # Then format the code...
43 dst_contents = black.format_str(src_contents, mode=mode)
44 except black.InvalidInput:
45 # This is a bug - if it's valid Python code, as above, Black should be
46 # able to cope with it. See issues #970, #1012, #1358, and #1557.
47 # TODO: remove this try-except block when issues are resolved.
50 # And check that we got equivalent and stable output.
51 black.assert_equivalent(src_contents, dst_contents)
52 black.assert_stable(src_contents, dst_contents, mode=mode)
54 # Future test: check that pure-python and mypyc versions of black
55 # give identical output for identical input?
58 if __name__ == "__main__":
59 test_idempotent_any_syntatically_valid_python()