view tests/hypothesishelpers.py @ 43699:21e05aabef8c

hghave: add a check for the `xz` compression utility

This isn't install by default on Mac, which causes a test failure.  The logic
for avoiding the command is a little goofy, but nested `#if` isn't supported,
and it still seems worth running the hg command to see if anything explodes.

With this, the py3 tests run (almost) cleanly on 10.14.6:

    # Ran 835 tests, 58 skipped, 1 failed.

Alas, the mac-packaging test is skipped because it's slow.  The failure here is
in test-releasenotes-merging.t, complaining about not being able to import the
`fuzzywuzzy` module.  I have it installed on py3 (thus the test isn't skipped),
but not on py2.  So there must be some unintended cross pollination here when
running `hg` commands.

Differential Revision: https://phab.mercurial-scm.org/D7374

# Helper module to use the Hypothesis tool in tests
#
# Copyright 2015 David R. MacIver
#
# For details see http://hypothesis.readthedocs.org

from __future__ import absolute_import, print_function
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()