tests: add tests and document expectations from visit_children_set in rust
The tests this patch are adding have the form of formal spec in
invariants::visit_children_set::holds,
and then a series of checks that all examples must satisfy this
formal spec.
I tried to make the spec consistent with how this function is used
and how it was originally conceived. This is in conflict with how it's
documented in Rust. Some of the implementations also fail to implement
this spec, which leads to bugs, in particular when complicated patterns
are used with `hg status`.
# Helper module to use the Hypothesis tool in tests
#
# Copyright 2015 David R. MacIver
#
# For details see http://hypothesis.readthedocs.org
import os
import sys
import traceback
try:
# hypothesis 2.x
from hypothesis.configuration import set_hypothesis_home_dir
from hypothesis import settings
except ImportError:
# hypothesis 1.x
from hypothesis.settings import set_hypothesis_home_dir
from hypothesis import Settings as settings
import hypothesis.strategies as st
from hypothesis import given
# hypothesis store data regarding generate example and code
set_hypothesis_home_dir(os.path.join(os.getenv('TESTTMP'), ".hypothesis"))
def check(*args, **kwargs):
"""decorator to make a function a hypothesis test
Decorated function are run immediately (to be used doctest style)"""
def accept(f):
# Workaround for https://github.com/DRMacIver/hypothesis/issues/206
# Fixed in version 1.13 (released 2015 october 29th)
f.__module__ = '__anon__'
try:
with settings(max_examples=2000):
given(*args, **kwargs)(f)()
except Exception:
traceback.print_exc(file=sys.stdout)
sys.exit(1)
return accept
def roundtrips(data, decode, encode):
"""helper to tests function that must do proper encode/decode roundtripping"""
@given(data)
def testroundtrips(value):
encoded = encode(value)
decoded = decode(encoded)
if decoded != value:
raise ValueError(
"Round trip failed: %s(%r) -> %s(%r) -> %r"
% (encode.__name__, value, decode.__name__, encoded, decoded)
)
try:
testroundtrips()
except Exception:
# heredoc swallow traceback, we work around it
traceback.print_exc(file=sys.stdout)
raise
print("Round trip OK")
# strategy for generating bytestring that might be an issue for Mercurial
bytestrings = (
st.builds(
lambda s, e: s.encode(e),
st.text(),
st.sampled_from(
[
'utf-8',
'utf-16',
]
),
)
) | st.binary()