view tests/hypothesishelpers.py @ 37533:df4985497986

wireproto: implement capabilities for wire protocol v2

The capabilities mechanism for wire protocol version 2 represents a
clean break from version 1.

Instead of effectively exchanging a set of capabilities, we're
exchanging a rich data structure.

This data structure currently contains information about
every available command, including its accepted arguments. It also
contains information about supported compression formats.

Exposing information about supported commands will allow clients
to automatically generate bindings to the server. Clients will be
able to do things like detect when they are attempting to run a
command that isn't known to the server. Exposing the required
permissions to run a command can be used by clients to determine if
they have privileges to call a command before actually calling it.
We could potentially even have clients send credentials
preemptively without waiting for the server to deny the command
request. Lots of potential here.

The data returned by this command will likely evolve heavily. So we
shouldn't bikeshed the implementation just yet.

Differential Revision: https://phab.mercurial-scm.org/D3200

# 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()