tests/hypothesishelpers.py

packaging: bundle dulwich, keyring, and pywin32-ctypes with WiX too

TortoiseHg installs these, which is possibly where they originated (though I
would have thought it more likely to be in the WiX installer, given its
heritage).  When I was working on the TortoiseHg app for Mac (which uses the
similar `py2app`), it wasn't possible to use the keyring extension (even
externally) without bundling this keyring package into the app.  Assuming the
same principle applies here, these would enable some common extensions.  One of
the things that the TortoiseHg packager on macOS does now is it adds the user's
local `site-packages` directory to `sys.path`.  That would allow the user to
install these critical modules in cases like this.  But that can probably wait
for py3 packaging.

The only difference in the installed packages that I see now is WiX also bundles
distutils for some reason.  I suppose that's not harming anything, so I'm not
touching it.

The only orphans in the install directories when comparing WiX and Inno now is
the Copying.txt vs COPYING.rtf, the two uninstaller files for Inno, and a
`Mercurial.url` file in Inno.  I have no idea what that is, and it has *.ini
syntax with a single field pointing to the Mercurial homepage.

Differential Revision: https://phab.mercurial-scm.org/D8062

# 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()